Game program, information processing system, information processing device, and game processing method

Abstract

To express the surface of an object after deformation using a new method when the object is deformed.SOLUTION: An information processing system updates voxel data in which at least the density and materials are set on the basis of game processing, and generates and updates a display mesh on the basis of the density and materials included in the voxel data. Drawing of a virtual space including the display mesh is performed on the basis of apex coordinates of the display mesh and a texture corresponding to the materials of the display mesh. When an event occurs on the basis of game processing, the information processing system performs an update for generating a first voxel update range in the virtual space, decreasing the density of each voxel corresponding to the first voxel update range in the virtual space of the voxel data, and changing the materials of each voxel corresponding to a second voxel update range of a size including the first voxel update range.SELECTED DRAWING: Figure 30

Description

Technical Field

[0001] The present invention relates to a game program, an information processing system, an information processing apparatus, and a game processing method for generating an object in a virtual space.

Background Art

[0002] Conventionally, objects have been managed using voxel data, and an object mesh has been generated in a virtual space based on the voxel data (see, for example, Non-Patent Document 1).

Prior Art Documents

Non-Patent Documents

[0003]

Non-Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] When an object is deformed, the surface of the object after deformation is expressed by a novel method.

Means for Solving the Problems

[0005] In order to solve the above problems, the present invention employs the following configurations (1) to (8).

[0006] (1) An example of the present invention is a game program that causes a computer of an information processing apparatus to execute the following processing. ·Voxel data defined in a virtual space, for each of a plurality of voxels, voxel data in which at least a density indicating the degree to which the space defined by the voxel is virtually occupied by the content and a material indicating the type of the content are set, is updated based on game processing ·Processing for generating and updating a display mesh corresponding to the voxel data and drawn based on a virtual camera, by determining vertex coordinates of the display mesh based on at least the density included in the voxel data and determining the material of the display mesh based on at least the material included in the voxel data ·Processing for performing drawing of a virtual space including the display mesh based on a texture corresponding to vertex coordinates of the display mesh and the material of the display mesh ·When a first event occurs based on game processing, generating a first voxel update range in the virtual space, decreasing the density of each voxel in the voxel data corresponding to the first voxel update range in the virtual space, and further performing an update for changing the material of each voxel corresponding to a second voxel update range having a size that encloses the first voxel update range

[0007] According to the configuration of (1) above, the surface of the voxel object can be expressed in a new method.

[0008] (2) In the configuration of (1) above, the game program may cause the computer to change the material of the voxels corresponding to the second voxel update range to a destination material preset for each type of the material before the change.

[0009] According to the configuration of (2) above, the material set after the change can be made to correspond to the material before the change.

[0010] (3) In the configuration of (2) above, the material of the voxel data may be held as a material ID indicating the material. The game program causes the computer to, for each type of material corresponding to the material ID, based on drawing setting information including at least texture information set for the material and material data including at least a destination material ID indicating a destination material corresponding to the material, change the material ID of the voxels corresponding to the second voxel update range to a destination material ID corresponding to the material indicated by the material ID.

[0011] According to the configuration of (3) above, the material before change and the material after change can be managed by the material data.

[0012] (4) In the configuration of (3) above, a plurality of material IDs may be held. The game program causes the computer to, based on the material data, change the respective material IDs of the voxels corresponding to the second voxel update range to the respective destination material IDs.

[0013] According to the configuration of (4) above, when a plurality of materials are set for a voxel, it is possible to reduce the possibility that the appearance of the voxel object becomes unnatural due to the change of the material.

[0014] (5) In any of the configurations of (1) to (4) above, the game program may cause the computer to change the material of the voxels corresponding to the second voxel update range to a first material regardless of the material before change.

[0015] According to the configuration of (5) above, the material of the voxel object can be changed to various types of materials without being restricted by the material before change.

[0016] (6) In any of the configurations (1) to (5) above, the second voxel update range may have a shape that expands the first voxel update range.

[0017] According to the configuration (6) above, a second voxel update range that encloses the first voxel update range can be easily generated.

[0018] (7) In any of the configurations (1) to (6) above, the game program may cause the computer to execute the following processing. · For a portion where a voxel having a density of a setting indicating existence and a voxel having a density of a setting indicating non-existence are adjacent based on the voxel data, based on a method of setting vertices at coordinates based on the positions and densities of a plurality of surrounding voxels, a process of generating and updating the vertices of the display mesh · When a first event occurs, a process of performing an update to reduce the density of each voxel corresponding to the first voxel update range to be equal to or less than the density of a setting indicating non-existence

[0019] According to the configuration (7) above, the mesh of the voxel object can be deformed into a shape corresponding to the shape of the first voxel update range.

[0020] (8) In any of the configurations (2) to (4) above, when a second event occurs based on game processing, the game program may further cause the computer to generate a third voxel update range in the virtual space and perform an update to change the material of each voxel corresponding to the third voxel update range in the virtual space to the destination material.

[0021] According to the configuration (8) above, the material can be changed without deforming the voxel object. For example, an expression that makes the surface of the voxel object appear to be thinly removed can be achieved without deforming the voxel object.

[0022] In addition, another example of the present invention may be an information processing apparatus or an information processing system that executes the processes in (1) to (8) above. Further, another example of the present invention may be a game processing method that causes an information processing system to execute the processes in (1) to (8) above.

Effects of the Invention

[0023] According to the game program, information processing system, information processing apparatus, or game processing method described above, when an object is deformed, the surface of the object after deformation can be expressed in a novel method.

Brief Description of the Drawings

[0024]

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[0025] [1. Configuration of the Game System] Hereinafter, a game system according to an example of the present embodiment will be described. An example of the game system 1 in the present embodiment includes a main body device (information processing device; which functions as the game device main body in the present embodiment) 2, a left controller 3, and a right controller 4. The main body device 2 is detachable from the left controller 3 and the right controller 4 respectively. That is, the game system 1 can be used as a device in which the left controller 3 and the right controller 4 are respectively attached to the main body device 2 and integrated. Also, the game system 1 can be used with the main body device 2, the left controller 3, and the right controller 4 as separate entities (see FIG. 2). Hereinafter, the hardware configuration of the game system 1 of the present embodiment will be described, and then the control of the game system 1 of the present embodiment will be described.

[0026] FIG. 1 is a diagram showing an example of a state in which a left controller 3 and a right controller 4 are attached to a main body device 2. As shown in FIG. 1, the left controller 3 and the right controller 4 are respectively attached to the main body device 2 and integrated. The main body device 2 is a device that executes various processes (for example, game processes) in the game system 1. The main body device 2 includes a display 12. The left controller 3 and the right controller 4 are devices that include an operation unit for the user to input.

[0027] FIG. 2 is a diagram showing an example of a state in which the left controller 3 and the right controller 4 are respectively removed from the main body device 2. As shown in FIGS. 1 and 2, the left controller 3 and the right controller 4 are detachable from the main body device 2. In the following, the left controller 3 and the right controller 4 may be collectively referred to as "controller".

[0028] FIG. 3 is a six-sided view showing an example of the main body device 2. As shown in FIG. 3, the main body device 2 includes a substantially plate-shaped housing 11. In the present embodiment, the main surface of the housing 11 (in other words, the front surface, that is, the surface on which the display 12 is provided) is generally rectangular.

[0029] Note that the shape and size of the housing 11 are arbitrary. As an example, the housing 11 may be of a portable size. Also, the main body device 2 alone or the integrated device in which the left controller 3 and the right controller 4 are attached to the main body device 2 may be a portable device. Further, the main body device 2 or the integrated device may be a hand-held device. Also, the main body device 2 or the integrated device may be a portable device.

[0030] As shown in FIG. 3, the main body device 2 includes a display 12 provided on the main surface of the housing 11. The display 12 displays an image generated by the main body device 2. In the present embodiment, the display 12 is a liquid crystal display device (LCD). However, the display 12 may be any type of display device.

[0031] In addition, the main body device 2 is provided with a touch panel 13 on the screen of the display 12. In the present embodiment, the touch panel 13 is of a type (for example, a capacitance type) capable of multi-touch input. However, the touch panel 13 may be of any type, for example, a type (for example, a resistive film type) capable of single-touch input may also be used.

[0032] The main body device 2 includes a speaker (that is, the speaker 88 shown in FIG. 6) inside the housing 11. As shown in FIG. 3, speaker holes 11a and 11b are formed in the main surface of the housing 11. Then, the output sound of the speaker 88 is output from these speaker holes 11a and 11b, respectively.

[0033] In addition, the main body device 2 includes a left terminal 17 which is a terminal for the main body device 2 to perform wired communication with the left controller 3, and a right terminal 21 for the main body device 2 to perform wired communication with the right controller 4.

[0034] As shown in FIG. 3, the main body device 2 includes a slot 23. The slot 23 is provided on the upper surface of the housing 11. The slot 23 has a shape capable of mounting a predetermined type of storage medium. The predetermined type of storage medium is, for example, a storage medium (for example, a dedicated memory card) dedicated to the game system 1 and information processing devices of the same type. The predetermined type of storage medium is used, for example, to store data (for example, save data of an application, etc.) used in the main body device 2 and / or programs (for example, application programs, etc.) executed by the main body device 2. In addition, the main body device 2 includes a power button 28.

[0035] The main body device 2 is provided with a lower terminal 27. The lower terminal 27 is a terminal for the main body device 2 to communicate with the cradle. In the present embodiment, the lower terminal 27 is a USB connector (more specifically, a female connector). When the integrated device or the main body device 2 alone is placed on the cradle, the game system 1 can display the image generated and output by the main body device 2 on a stationary monitor. Further, in the present embodiment, the cradle has a function of charging the placed integrated device or the main body device 2 alone. Further, the cradle has a function of a hub device (specifically, a USB hub).

[0036] FIG. 4 is a six-sided view showing an example of the left controller 3. As shown in FIG. 4, the left controller 3 includes a housing 31. In the present embodiment, the housing 31 has a vertically long shape, that is, a shape that is long in the vertical direction (that is, the y-axis direction shown in FIGS. 1 and 4). When the left controller 3 is removed from the main body device 2, it can also be gripped in a vertically long orientation. The housing 31 has a shape and size that can be gripped with one hand, particularly the left hand, when gripped in a vertically long orientation. Further, the left controller 3 can also be gripped in a horizontally long orientation. When the left controller 3 is gripped in a horizontally long orientation, it may be gripped with both hands.

[0037] The left controller 3 includes an analog stick 32. As shown in FIG. 4, the analog stick 32 is provided on the main surface of the housing 31. The analog stick 32 can be used as a direction input unit capable of inputting a direction. The user can input a direction according to the tilting direction (and an input of a magnitude according to the tilted angle) by tilting the analog stick 32. Note that the left controller 3 may be provided with a cross key or a slide stick capable of slide input instead of the analog stick as a direction input unit. Further, in the present embodiment, it is possible to input by pressing the analog stick 32.

[0038] The left controller 3 is provided with various operation buttons. The left controller 3 has four operation buttons 33 to 36 (specifically, a right direction button 33, a down direction button 34, an up direction button 35, and a left direction button 36) on the main surface of the housing 31. Further, the left controller 3 is provided with a recording button 37 and a -(minus) button 47. The left controller 3 has a first L button 38 and a ZL button 39 at the upper left of the side surface of the housing 31. Also, the left controller 3 has a second L button 43 and a second R button 44 on the side surface of the housing 31 on the side that is attached when the left controller 3 is attached to the main body device 2. These operation buttons are used to give instructions according to various programs (for example, an OS program or an application program) executed by the main body device 2.

[0039] Also, the left controller 3 is provided with a terminal 42 for the left controller 3 to perform wired communication with the main body device 2.

[0040] FIG. 5 is a six-sided view showing an example of the right controller 4. As shown in FIG. 5, the right controller 4 includes a housing 51. In the present embodiment, the housing 51 has a vertically long shape, that is, a shape that is long in the vertical direction. The right controller 4 can also be gripped in a vertically long orientation when removed from the main body device 2. The housing 51 has a shape and size that can be gripped with one hand, particularly the right hand, when gripped in a vertically long orientation. Also, the right controller 4 can be gripped in a horizontally long orientation. When the right controller 4 is gripped in a horizontally long orientation, it may be gripped with both hands.

[0041] Similar to the left controller 3, the right controller 4 includes an analog stick 52 as a direction input unit. In this embodiment, the analog stick 52 has the same configuration as the analog stick 32 of the left controller 3. Further, instead of the analog stick, the right controller 4 may be provided with a cross key or a slide stick capable of slide input. Also, similar to the left controller 3, the right controller 4 includes four operation buttons 53 to 56 (specifically, an A button 53, a B button 54, an X button 55, and a Y button 56) on the main surface of the housing 51. Furthermore, the right controller 4 includes a + (plus) button 57 and a home button 58. Also, the right controller 4 includes a first R button 60 and a ZR button 61 at the upper right of the side surface of the housing 51. Also, similar to the left controller 3, the right controller 4 includes a second L button 65 and a second R button 66.

[0042] Also, the right controller 4 includes a terminal 64 for the right controller 4 to perform wired communication with the main body device 2.

[0043] FIG. 6 is a block diagram showing an example of the internal configuration of the main body device 2. In addition to the configuration shown in FIG. 3, the main body device 2 includes each of the components 81 to 91, 97, and 98 shown in FIG. 6. Some of these components 81 to 91, 97, and 98 may be mounted on an electronic circuit board as electronic components and housed in the housing 11.

[0044] The main body device 2 includes a processor 81. The processor 81 is an information processing unit that executes various information processes to be executed in the main body device 2. For example, it may be composed of only a CPU (Central Processing Unit), or may be composed of a SoC (System-on-a-chip) including a plurality of functions such as a CPU function and a GPU (Graphics Processing Unit) function. The processor 81 executes various information processes by executing an information processing program (for example, a game program) stored in a storage unit (specifically, an internal storage medium such as a flash memory 84, or an external storage medium mounted on the slot 23, etc.).

[0045] As an example of an internal storage medium built in the main body device 2, the main body device 2 includes a flash memory 84 and a DRAM (Dynamic Random Access Memory) 85. The flash memory 84 and the DRAM 85 are connected to the processor 81. The flash memory 84 is mainly a memory used to store various data (which may be a program) stored in the main body device 2. The DRAM 85 is a memory used to temporarily store various data used in information processing.

[0046] The main body device 2 includes a slot interface (hereinafter abbreviated as "I / F") 91. The slot I / F 91 is connected to the processor 81. The slot I / F 91 is connected to the slot 23, and reads and writes data to and from a predetermined type of storage medium (for example, a dedicated memory card) mounted on the slot 23 according to an instruction from the processor 81.

[0047] The processor 81 appropriately reads and writes data between the flash memory 84 and the DRAM 85, and the above storage media, and executes the above information processes.

[0048] The main body device 2 includes a network communication unit 82. The network communication unit 82 is connected to the processor 81. The network communication unit 82 communicates (specifically, wirelessly communicates) with an external device via a network. In the present embodiment, the network communication unit 82 connects to a wireless LAN and communicates with an external device by a method compliant with the Wi-Fi (registered trademark) standard as a first communication mode. Further, the network communication unit 82 performs wireless communication with other main body devices 2 of the same type by a predetermined communication method (for example, communication by a proprietary protocol or infrared communication) as a second communication mode. Note that the wireless communication by the second communication mode enables wireless communication with other main body devices 2 arranged within a closed local network area, and realizes a function that enables so-called "local communication" in which data is transmitted and received by direct communication between a plurality of main body devices 2.

[0049] The main body device 2 includes a controller communication unit 83. The controller communication unit 83 is connected to the processor 81. The controller communication unit 83 performs wireless communication with the left controller 3 and / or the right controller 4. The communication method between the main body device 2 and the left controller 3 and the right controller 4 is arbitrary. However, in the present embodiment, the controller communication unit 83 communicates with the left controller 3 and the right controller 4 in accordance with the Bluetooth (registered trademark) standard.

[0050] The processor 81 is connected to the above-described left terminal 17, right terminal 21, and lower terminal 27. When the processor 81 performs wired communication with the left controller 3, it transmits data to the left controller 3 via the left terminal 17 and receives operation data from the left controller 3 via the left terminal 17. Also, when the processor 81 performs wired communication with the right controller 4, it transmits data to the right controller 4 via the right terminal 21 and receives operation data from the right controller 4 via the right terminal 21. Further, when the processor 81 communicates with the cradle, it transmits data to the cradle via the lower terminal 27. Thus, in the present embodiment, the main body device 2 can perform both wired communication and wireless communication with the left controller 3 and the right controller 4, respectively. Also, when the left controller 3 and the right controller 4 are attached to the main body device 2 as an integrated device or when the main body device 2 alone is attached to the cradle, the main body device 2 can output data (for example, image data and audio data) to a stationary monitor or the like via the cradle.

[0051] Here, the main body device 2 can communicate with a plurality of left controllers 3 simultaneously (in other words, in parallel). Also, the main body device 2 can communicate with a plurality of right controllers 4 simultaneously (in other words, in parallel). Therefore, a plurality of users can simultaneously input to the main body device 2 using sets of the left controller 3 and the right controller 4, respectively. As an example, while the first user inputs to the main body device 2 using the first set of the left controller 3 and the right controller 4, it is possible for the second user to input to the main body device 2 using the second set of the left controller 3 and the right controller 4.

[0052] Also, the display 12 is connected to the processor 81. The processor 81 displays an image generated (for example, by executing the above-described information processing) and / or an image acquired from the outside on the display 12.

[0053] The main body device 2 includes a codec circuit 87 and speakers (specifically, a left speaker and a right speaker) 88. The codec circuit 87 is connected to the speakers 88 and the audio input / output terminal 25, and is also connected to the processor 81. The codec circuit 87 is a circuit that controls the input / output of audio data to / from the speakers 88 and the audio input / output terminal 25.

[0054] The main body device 2 includes a power control unit 97 and a battery 98. The power control unit 97 is connected to the battery 98 and the processor 81. Also, although not shown, the power control unit 97 is connected to each part of the main body device 2 (specifically, each part that receives power supply from the battery 98, the left terminal 17, and the right terminal 21). The power control unit 97 controls the power supply from the battery 98 to each of the above parts based on a command from the processor 81.

[0055] Also, the battery 98 is connected to the lower terminal 27. When an external charging device (for example, a cradle) is connected to the lower terminal 27 and power is supplied to the main body device 2 via the lower terminal 27, the supplied power is charged to the battery 98.

[0056] FIG. 7 is a block diagram showing an example of the internal configuration of the main body device 2, the left controller 3, and the right controller 4. Note that the details of the internal configuration regarding the main body device 2 are shown in FIG. 6, and thus are omitted in FIG. 7.

[0057] The left controller 3 includes a communication control unit 101 that communicates with the main body device 2. As shown in FIG. 7, the communication control unit 101 is connected to each component including the terminal 42. In the present embodiment, the communication control unit 101 can communicate with the main body device 2 both by wired communication via the terminal 42 and by wireless communication without using the terminal 42. The communication control unit 101 controls the communication method that the left controller 3 performs with respect to the main body device 2. That is, when the left controller 3 is attached to the main body device 2, the communication control unit 101 communicates with the main body device 2 via the terminal 42. Further, when the left controller 3 is detached from the main body device 2, the communication control unit 101 performs wireless communication with the main body device 2 (specifically, the controller communication unit 83). The wireless communication between the controller communication unit 83 and the communication control unit 101 is performed in accordance with, for example, the Bluetooth (registered trademark) standard.

[0058] In addition, the left controller 3 includes a memory 102 such as a flash memory. The communication control unit 101 is composed of, for example, a microcomputer (also referred to as a microprocessor), and executes various processes by executing the firmware stored in the memory 102.

[0059] The left controller 3 includes each button 103 (specifically, buttons 33 to 39, 43, 44, and 47). Further, the left controller 3 includes an analog stick (described as "stick" in FIG. 7) 32. Each button 103 and the analog stick 32 output information regarding the operation performed on themselves to the communication control unit 101 repeatedly at an appropriate timing.

[0060] The communication control unit 101 acquires information regarding the input (specifically, information regarding the operation or the detection result by the sensor) from each input unit (specifically, each button 103 and the analog stick 32). The communication control unit 101 transmits operation data including the acquired information (or information obtained by performing predetermined processing on the acquired information) to the main body device 2. Note that the operation data is repeatedly transmitted at a rate of once every predetermined time. Note that the intervals at which the information regarding the input is transmitted to the main body device 2 may be the same or different for each input unit.

[0061] By transmitting the above operation data to the main body device 2, the main body device 2 can obtain the input performed on the left controller 3. That is, the main body device 2 can determine the operations on each button 103 and the analog stick 32 based on the operation data.

[0062] The left controller 3 includes a power supply unit 108. In the present embodiment, the power supply unit 108 has a battery and a power control circuit. Although not shown, the power control circuit is connected to the battery and is also connected to each part of the left controller 3 (specifically, each part that receives power supply from the battery).

[0063] As shown in FIG. 7, the right controller 4 includes a communication control unit 111 that communicates with the main body device 2. The right controller 4 also includes a memory 112 connected to the communication control unit 111. The communication control unit 111 is connected to each component including the terminal 64. The communication control unit 111 and the memory 112 have the same functions as the communication control unit 101 and the memory 102 of the left controller 3. Therefore, the communication control unit 111 can communicate with the main body device 2 by both wired communication via the terminal 64 and wireless communication without using the terminal 64 (specifically, communication conforming to the Bluetooth (registered trademark) standard), and controls the communication method that the right controller 4 performs with the main body device 2.

[0064] The right controller 4 includes the same input units as each input unit of the left controller 3. Specifically, it includes each button 113 and the analog stick 52. These input units have the same functions as the input units of the left controller 3 and operate in the same manner.

[0065] The right controller 4 includes a power supply unit 118. The power supply unit 118 has the same function as the power supply unit 108 of the left controller 3 and operates in the same manner.

[0066] [2. Overview of Processing in the Game System] Next, with reference to FIGS. 8 to 29, an overview of the processing executed in the game system 1 will be described. In the present embodiment, the game system 1 generates a game image in which terrain objects and characters (for example, player characters operated by a player) are arranged in a game space that is a three-dimensional virtual space, and causes the display device to display it. Note that, in the present embodiment, the display device on which the game image is displayed may be the above-described display 12 or a stationary monitor.

[0067] [2-1. Voxels] In the present embodiment, for some objects in the game space, the shape is defined by voxel data. Here, a voxel is a rectangular parallelepiped (more specifically, a cubic) region arranged in a grid pattern in the game space, and voxel data is data indicating information regarding each voxel. Hereinafter, an object whose shape is defined by voxel data will be referred to as a "voxel object". In the present embodiment, the game system 1 stores voxel data as data for generating voxel objects in the game space for a plurality of voxels set in the game space.

[0068] FIG. 8 is a diagram showing an example of a terrain object that is a voxel object. As shown in FIG. 8, in the present embodiment, a terrain object representing a terrain such as the ground is defined in shape by voxel data (that is, it is a voxel object). Each cube shown in FIG. 8 represents a terrain object. In FIG. 8, the portions that are the sides of the terrain object are shown as thick lines, but these thick lines are added for the purpose of making the drawing easier to view, and in reality, the sides of the terrain object do not need to be shown thickly.

[0069] Note that the terrain object shown in FIG. 8 is generated, for example, according to the rule that "if the parameter included in the voxel data set for a voxel is greater than a predetermined value, a cube is placed at the position of the voxel, and if it is less than or equal to the predetermined value, nothing is placed at the position of the voxel". The terrain object shown in FIG. 8 is shown for the purpose of easily exemplifying the relationship between voxels and voxel objects. In the present embodiment, in reality, for example, like the terrain object shown in FIG. 13 described later, a voxel object is generated according to a rule that results in a complex shape (based on voxel data). Note that the rule for determining the shape of the voxel object based on voxel data is arbitrary. In other embodiments, the game system 1 may generate a voxel object as shown in FIG. 8 or a voxel object as shown in FIG. 13 based on object data.

[0070] Regarding the voxel object, the shape can be changed by changing the voxel data of each voxel. FIGS. 9 and 10 are diagrams showing an example of the state before and after a part of the terrain object shown in FIG. 8 is deleted. That is, when the hatched portion of the terrain object shown in FIG. 9 is destroyed, the terrain object changes to the shape shown in FIG. 10. At this time, the game system 1 can easily erase the terrain object by rewriting the voxel data described later so as to indicate that there is no terrain object for the voxels in the hatched portion. Note that when the game system 1 adds a terrain object, it can easily change the shape of the terrain object by changing the voxel data of each voxel in the same manner as when erasing the terrain object.

[0071] In this way, the game system 1 can freely change the shape of the voxel object by rewriting the voxel data. For example, when the shape of a terrain object changes as a result of being destroyed for some reason (e.g., a player character strikes the terrain object) in the game, the game system 1 does not directly change the data indicating the outer shape of the terrain object (i.e., the mesh described later), but can freely change the shape of the terrain object by changing the voxel data used for generating the terrain object.

[0072] In the present embodiment, it is assumed that voxels are defined throughout the game space (that is, the voxel space in which voxels are set corresponds to the entire game space). However, the voxel space does not necessarily have to be set throughout the game space and may be set in a partial region of the game space. When the voxel space is set in a partial region of the game space, the shape of the voxel object is defined by voxel data regarding the voxels in the voxel space, and the position of the voxel object in the game space is defined by the position of the voxel space in the game space. Also, in the game space, a main voxel space set throughout the game space and a sub-voxel space set in a partial region of the game space may be set. At this time, the game system 1 stores voxel data for each voxel space.

[0073] FIG. 11 is a diagram showing an example of voxel data. The voxel data includes density data, a first material ID, a second material ID, material mixing ratio data, and state data for each voxel defined in the game space. In the voxel data in the present embodiment, these data are set for each voxel.

[0074] The density data indicates the density which is an index used to define the shape of the voxel object based on the voxel (specifically, the shape defined by a mesh described later). Although details will be described later, the position and shape of the surface of the voxel object (that is, the mesh described later) are determined based on the above density.

[0075] In this embodiment, the density can take an integer value in the range from a lower limit value (for example, 0) to an upper limit value (for example, 255). In this embodiment, when the value of the density set for a voxel is high, the ratio of the volume occupied by the region within the voxel object in the voxel tends to be large, and when the value of the density is low, the ratio tends to be small. Based on the density, the surface shape of the voxel object is determined. Thus, the density is an index that affects the ratio of the volume occupied by the region within the voxel object in the voxel. It can also be said that the density is an index indicating the degree to which the space of the voxel is virtually occupied by the content (i.e., the virtual content of the voxel object). For example, when the density is 0, the inside of the voxel is empty, when the density is 255, all of the inside of the voxel is the content of the voxel object, and when the density is a value between 0 and 255, the inside of the voxel can be occupied by the content of the voxel object at a ratio corresponding to the value. Then, based on the above density, the shape of the mesh, that is, the surface shape of the voxel object can be determined. The mesh can also be said to be the surface of the part where the content exists in the voxel, or the boundary between the part where the content exists and the part where it does not exist in the voxel. Note that the volume occupied by the region within the voxel object generated based on the above density does not have to be exactly the volume corresponding to the ratio indicated by the density. For example, in the method of generating a voxel object as shown in FIG. 8 and the method of generating a voxel object as shown in FIG. 13, even if based on the same density, the volume of the voxel object may be different.

[0076] In other embodiments, the density may indicate either a state in which the volume occupied by the region within the voxel object occupies the entire region within the voxel or a state in which the volume occupied by the region within the voxel object is not included in the region within the voxel. For example, the density data may be data that can only take 0 or 1.

[0077] The first material ID and the second material ID are information indicating the material (in other words, substance) of the voxel. Here, in the present embodiment, materials such as sand, rock, or soil are set for the voxel. Note that in the game system 1, a plurality of types of materials are prepared as materials that can be set for the voxel (refer to the material data shown in FIG. 12). In the present embodiment, up to two materials out of the plurality of types of prepared materials can be set for one voxel. The first material ID is an ID indicating the first material set for the voxel, and the second material ID is an ID indicating the second material set for the voxel. Although details will be described later, the material of the voxel object (that is, the material set for the polygon of the voxel object) is determined based on the material set for the voxel.

[0078] As described above, in the present embodiment, the voxel data includes the ID indicating the material. However, in other embodiments, the voxel data may be a data structure including data directly indicating the content of the material (that is, the name, properties, and drawing setting information described later).

[0079] The material mixing ratio data is an example of data indicating the ratio of each material in the voxel. In the present embodiment, since the number of material IDs set in one voxel is up to two, the material mixing ratio data indicating the ratio of one of the materials indicated by the first material ID and the material indicated by the second material ID can also represent the other ratio. In the present embodiment, the material mixing ratio is a value indicating the ratio of the second material to the whole composed of the first material and the second material by a value of 0 or more and 1 or less. For example, when the material mixing ratio set in a certain voxel is 0.4, it represents that in the voxel, the first material and the second material are composed in a ratio of 0.6:0.4. Although details will be described later, the appearance and properties of the voxel object are determined based on the material. The material mixing ratio is used to determine the appearance and properties of the voxel object. In other embodiments, the material mixing ratio may be a value indicating the ratio of the first material. Also, the ratio of the materials in the voxel may be represented by respective values indicating the ratio of each material. In particular, in other embodiments, when three or more materials can be set instead of up to two types of materials, the ratio of the materials in the voxel is represented as a plurality of values respectively indicating the ratio of each material.

[0080] Note that in the present embodiment, it is not always necessary to set two types of materials in the voxel, and one type of material may be set. For example, when one type of material is set in a certain voxel, the first material ID indicates the material, and the material mixing ratio is set to 0.

[0081] The state data indicates the state set in the voxel. The specific content and number of types of the state data are arbitrary. In the present embodiment, the state data includes data indicating the amount of damage set in the voxel. Note that in other embodiments, the state data may include data indicating, for example, whether the voxel is wet (and the degree thereof).

[0082] As described above, in this embodiment, since the voxel data includes the material ID, the game system 1 stores material data that defines the content of the material indicated by the material ID. FIG. 12 is a diagram showing an example of the material data. As shown in FIG. 12, in the material data in this embodiment, for each material, the material ID is associated with the name, properties, drawing settings, and internal material ID information set for the material.

[0083] The name included in the material data is the name set for the material (for example, soil, sand, grass, etc.). Although details will be described later, during the game, the name of the material of the voxel object may be displayed (see FIG. 28). To perform such display, the material data includes information on the name of the material.

[0084] The properties included in the material data are the properties set for the material. The properties of the material are the properties that the voxel object to which the material is set has in the game. Note that the specific content and number of types of the properties of the material are arbitrary. For example, at least any of the following information may be set as the properties of the material. · Hardness · Weight · Slipperiness · Damage setting when the player character touches · Temperature · Whether another object can adhere to the voxel object · Amount of the player character's physical strength recovered when the player character destroys or acquires the voxel object · Amount of in-game currency acquired by the player character when the player character destroys or acquires the voxel object In other embodiments, information different from the above may be set as the information indicating the properties of the material.

[0085] In this embodiment, the material data includes, as information specifying the properties of the material, an ID indicating the property (see FIG. 12). Although not shown, the game system 1 stores property information in which, for each prepared property, the content of the property (for example, a value indicating the above-described weight or slipperiness) is associated with the property ID. By referring to the above property information, the game system 1 can specify the specific content of the property set for the material.

[0086] The rendering settings included in the material data are information indicating rendering-related settings, such as the texture used for rendering the voxel object to which the material is set. In this embodiment, the material data includes, as information on the rendering settings, the ID of the texture used for rendering the voxel object to which the material is set (see FIG. 12). Although not shown, the game system 1 stores texture information in which, for each prepared texture, the texture ID and the texture indicated by the texture ID are associated. By referring to the above texture information, the game system 1 can specify the specific content of the texture set for the material. In other embodiments, as information on the rendering settings, in addition to the texture information, any information related to the shading settings may be set. For example, the reflectivity, information related to the normal, etc. may be set.

[0087] As shown in FIG. 12, in the material data of the present embodiment, an internal material ID is associated with a material ID. When the material ID to which the internal material ID is associated indicates the material of the outer part of an object, the internal material ID indicates the material of the inner part of the object (hereinafter referred to as the "internal material"). For example, the ID of the material representing the outer bark of a tree may be associated with the ID of the material representing the inside of the tree as the internal material ID. Also, for example, the ID of the material representing the ground surface of grass may be associated with the ID of the material representing the soil inside when the grass on the ground surface is peeled off as the internal material ID. In the present embodiment, the internal material is preset for each type of material. However, depending on the type of material, there may be a material for which no internal material is set, that is, a material for which no internal material ID is associated with the material ID. Although details will be described later, the internal material is used as the destination material when a material change process is executed on the voxel in which the material to which the internal material is associated is set (see [2-8. Material Change] described later).

[0088] Note that in the material data of the present embodiment, the same value as the ID set as the internal material ID is set as the material ID. For example, in the example shown in FIG. 12, the ID of the soil material (001 in FIG. 12), which is the internal material ID associated with the ID of the grass material (003 in FIG. 12), is also set as the material ID. Therefore, by referring to the material data, it is possible to specify the name, properties, and drawing setting information associated with the internal material ID. Note that the material data may be any data structure that can specify information corresponding to the internal material ID. The material data may be a data structure in which the name, properties, and drawing setting information are indirectly associated with the internal material ID as described above, or a data structure in which these information are directly associated with the internal material ID.

[0089] Also, the material data may include data other than the data shown in FIG. 12. For example, the material data may include data related to sound settings. For example, the data related to sound settings may be data that defines the footsteps output when the player character walks on the voxel object based on the voxel.

[0090] Note that the material data may be data in any format that can identify the properties of the material and / or the rendering settings. For example, in other embodiments, the material data may have a data structure that includes data directly indicating the properties of the material and / or the rendering settings instead of a data structure that includes a material ID and a texture ID.

[0091] [2-2. Update of Voxel Data] During the game, the voxel object is deformed by updating the above-described voxel data. In this embodiment, when a game event (hereinafter referred to as an "update event") for updating the voxel object occurs, the game system 1 updates the voxel data. The specific content of the update event is arbitrary. The update event may be, for example, that a character appearing in the game performs an action to deform the voxel object (for example, the player character punches the voxel object), or an event that deforms the voxel object occurs (for example, an object thrown by a character contacts the voxel object, or a bomb explodes).

[0092] FIG. 13 is a diagram showing an example of a game space when an update event occurs. The situation shown in FIG. 13 is a situation where the player character 201 has performed a punch action on the terrain object 202 which is a voxel object. Although details will be described later, in the example shown in FIG. 13, the voxel data is updated so that the terrain object 202 around the position where the punch action by the player character 201 hits is erased. Thereby, the state where the terrain object 202 is destroyed by the punch action by the player character 201 is expressed.

[0093] In the present embodiment, when an update event occurs, the game system 1 sets an update range (update range 203 in the example shown in FIG. 13) for updating the voxel object in the game space. The position, shape, and size of the update range are arbitrary. The position of the update range may be determined based on, for example, the position where the object related to the occurred update event (for example, the player character who performed the punch) and the voxel object are in contact. In the example shown in FIG. 13, the position of the update range 203 may be determined based on the position where the punch by the player character 201 hits. For example, the hit position or the position a predetermined distance ahead from the hit position may be set as the center position of the update range 203. The shape and size of the update range may be determined in advance to be a shape corresponding to the type of the update event. For example, when an update event due to the punch of the player character 201 occurs, the shape and size of the update range may be determined as a sphere of a predetermined size as shown in FIG. 13. Further, the size of the update range may be determined according to a value indicating the degree of influence of the occurred update event (for example, the strength of the punch or the size of the explosion).

[0094] The game system 1 changes the density for the voxels corresponding to the set update range. Note that the voxels corresponding to the update range are, for example, the voxels within the update range or the voxels overlapping with the update range. As a result of the density change, the mesh of the voxel object is changed by the process described later, so that the shape of the voxel object (the visible shape and the shape used for collision detection) is changed. Note that in other embodiments, in addition to changing the density for the voxels included in the update range, the game system 1 may change the material (that is, the first material, the second material, and the material mixing ratio) in the voxels or change the state in the voxels.

[0095] In this embodiment, the game system 1 determines whether a voxel is included in the update range using an SDF (Signed Distance Field). The game system 1 sets an SDF indicating the update range set in the game space and makes the above determination based on the value of the SDF. The SDF represents the signed distance from a defined shape for any position. FIG. 14 is a diagram showing an example of the update range. In the example shown in FIG. 14, a spherical update range is set in the game space. For example, in the example shown in FIG. 14, among the positions in the game space, the SDF is set such that the value of the SDF is negative for the positions inside the shape represented by the SDF and the value of the SDF is positive for the positions outside the shape represented by the SDF. In this example, it is possible to determine whether it is included in the update range based on whether the value of the SDF is positive or negative. Also, by using the value of the signed distance, not only simple inside / outside determination but also processes such as correction and interpolation can be performed.

[0096] In the above, an example in which a change is added to the voxel object such that the voxel object within the update range is deformed as if it were erased has been described. However, the changes added to the voxel object using the update range are not limited to this. For example, a change in which a voxel object is newly added within the update range (that is, the volume occupied by the area within the voxel object increases by the amount of the update range) may be added to the voxel object (see FIG. 29 described later). Further, a change may be added to the voxel object such that only the material of the voxels within the update range changes without changing the density of the voxels. Further, a change combining a change in the density of the voxels and a change in the material may be added.

[0097] [2-3. Calculation of vertices] When the density of the voxels is updated as described above, the game system 1 sets vertices based on the updated voxel data. The above vertices can be the vertices of the mesh of the voxel object. Although details will be described later, in the present embodiment, the above vertices are simplified, and the simplified vertices become the vertices of the mesh of the voxel object.

[0098] FIG. 15 is a diagram showing an example of a method for setting vertices. In FIGS. 15 to 24 described below, for the purpose of making the drawing easy to view and the explanation easy to understand, voxels, vertices, meshes, etc. are represented two-dimensionally, but in reality, vertices and meshes are set in three-dimensional space based on the voxels in three-dimensional space. In the present embodiment, the game system 1 uses a method of setting vertices at coordinates based on the positions and densities of a plurality of surrounding voxels for a portion where a voxel having a set density indicating its existence (that is, a density equal to or greater than a reference value described later) and a voxel having a set density indicating its non-existence (that is, a density less than the reference value described later) are adjacent. Hereinafter, the details of this method will be described.

[0099] As described above, in this embodiment, the density set for each voxel is set in the range of 0 to 255. A voxel with a density of 0 is completely in the air, and a voxel with a density of 255 represents a state where it is completely filled. Densities between 0 and 255 are treated interpolatively and used for vertex determination. And in this embodiment, voxels with a density equal to or higher than a reference value are virtually treated as being inside the object, and voxels with a density lower than the reference value are treated as being outside the object. It can also be said that voxels with a density equal to or higher than the reference value are virtually treated as voxels indicating their existence, and voxels with a density lower than the reference value are virtually treated as voxels indicating their non-existence. It is not necessary to define only voxels with a density of 0 as being outside the object (i.e., set the reference value to 1), and the reference value can be, for example, 128. In the example shown in FIG. 15, assume that the density is 0 in voxel 211 and other outer voxels, the density of voxel 212 is 100 which is lower than the reference value, and the densities of voxels 213 and 214 are 150 and 210 which are equal to or higher than the reference value. In this embodiment, the game system 1 generates vertices between voxels with a density equal to or higher than the reference value and voxels with a density lower than the reference value. Specifically, for each region spanning eight (four in the drawing) adjacent voxels (the region surrounded by the dotted line in the drawing), a determination is made as to whether to generate a vertex. That is, vertices are generated in regions that span both voxels with a density equal to or higher than the reference value and voxels with a density lower than the reference value. The coordinates of the vertices are determined by comparing the densities of adjacent voxels for each of the X, Y, and Z axes and performing interpolation based on the density difference. By setting normal information that defines the position and orientation of the straight line connecting the vertices, the coordinates of the vertices can be further calculated based on the normal information. Note that the normal information may be retained in advance for at least some of the voxels, or if it is not retained, the normal information may also be calculated based on the densities of adjacent voxels. In FIG. 15, since the density of voxel 212 is lower than the reference value, voxel 212 is treated as being outside the object in the determination of the presence or absence of vertices, but the density value of voxel 212 itself is used for the calculation of the coordinates of the generated vertices.If the reference value is set to a value lower than the density of voxel 212, the number of vertices will further increase on the upper right side and the upper left side of voxel 212 in FIG. 15.

[0100] By setting the vertices as described above, when generating a mesh that connects each of the set vertices (or each vertex after performing the simplification process described later on each of the set vertices), a shape having a volume that reflects the density of each voxel to some extent can be generated. However, depending on the relationship with adjacent voxels, it is possible that a voxel with a density of 0 includes a region within the object, or a voxel with a density of 255 includes a region outside the object. Also, in this embodiment, since voxels with a value less than the reference value are processed as outside the object, the volume is also smaller because the number of vertices is smaller compared to the case of processing them as inside the object. Thus, it is not necessary to calculate the polygon mesh so as to have a volume that exactly corresponds to the density value.

[0101] [2-4. Determination of Vertex Material] The game system 1 determines the material for each of the vertices set as described above. The material of a vertex is determined based on the materials of the voxels around the vertex. The voxels around a vertex are, for example, the voxels used to determine whether to generate the vertex (that is, the voxels that overlap with the "region spanning voxels" described above). Note that in other embodiments, the voxels used to determine the material of a vertex do not have to be the same as the voxels used to determine the generation of the vertex, and they may be different.

[0102] FIG. 16 is a diagram showing an example of a method for determining the material of a vertex. In the example shown in FIG. 16, it is assumed that a vertex 219 is set for four voxels 215 to 218, and the four voxels 215 to 218 are the above-mentioned "voxels around the vertex". In the actual three-dimensional space, the number of voxels around the vertex is eight. Also, in the example shown in FIG. 16, for voxel 215, the density is set to 255, the first material is "sand", and the material mixing ratio is 0 (that is, the first material: the second material = 1:0, or the second material may not be set). For voxel 216, the density is set to 0 (the first and second materials may not be set). For voxel 217, the density is set to 204, the first material is "sand", the second material is "grass", and the material mixing ratio is 0.3 (that is, the first material: the second material = 0.7:0.3). For voxel 218, the density is set to 153, the first material is "soil", the second material is "grass", and the material mixing ratio is 0.4 (that is, the first material: the second material = 0.6:0.4). Also, the coordinates indicating the position of vertex 219 are assumed to be (X, Y) = (0.8, 0.6). Note that the coordinate system of these coordinates has the left-right direction in FIG. 16 as the X coordinate, the up-down direction as the Y coordinate, and the center position of the lower-left voxel 217 among the center positions of voxels 215 to 218 (the position of the white circle shown in FIG. 13) as (0, 0).

[0103] When determining the material of a vertex, the game system 1 calculates an evaluation value for each material in the surrounding voxels based on the density of the material and a weight value based on the distance from the voxel to the vertex. First, the weight value is calculated for each voxel, and is calculated so that it becomes larger as the distance from the center position of the voxel to the vertex is closer. In the present embodiment, when the center position of the voxel is (x1, y1) and the coordinates of the vertex are (x2, y2), the weight value for a certain voxel is calculated according to the following formula (1). (Weight value) = |(1 - x1) - x2|·|(1 - y1) - y2|…(1) In the example shown in FIG. 16, the weight values of each of the voxels 215 to 218 calculated according to the above formula (1) are as follows. (Weight value of voxel 215)=|(1 - 0) - 0.8|·|(1 - 1) - 0.6| = 0.12 (Weight value of voxel 216)=|(1 - 1) - 0.8|·|(1 - 1) - 0.6| = 0.48 (Weight value of voxel 217)=|(1 - 0) - 0.8|·|(1 - 0) - 0.6| = 0.08 (Weight value of voxel 218)=|(1 - 1) - 0.8|·|(1 - 0) - 0.6| = 0.32

[0104] Also, the game system 1 calculates the density of the material for each voxel. Here, the density of the material is a value obtained by multiplying the ratio of the material occupied by the material among the materials set in the voxel by the density of the voxel. In the present embodiment, as the density of the voxel, a value obtained by normalizing the above-described value from 0 to 255 to a value from 0 to 1 is used. In the example shown in FIG. 16, for voxel 215, since the only material set is sand, the above ratio regarding the sand material is 1, and the density of the voxel is 1, so the density of the sand material is 1. For voxel 216, since the density is 0 and no material is set, the density of the material is not calculated. Or, if some material is set, the density of the material is 0. For voxel 217, the above ratios of the set sand material and grass material are 0.7 and 0.3, respectively, and the density of the voxel is 204 / 255 = 0.8, so the density of the sand material is 0.7·0.8 = 0.56, and the density of the grass material is 0.3·0.8 = 0.24. For voxel 218, the above ratios of the set soil material and grass material are 0.6 and 0.4, respectively, and the density of the voxel is 153 / 255 = 0.6, so the density of the soil material is 0.6·0.6 = 0.36, and the density of the soil material is 0.4·0.6 = 0.24.

[0105] Then, the game system 1 calculates the above evaluation value for each material based on the above weight value and the density of the material. In the present embodiment, the evaluation value of the material is a value obtained by attaching a weight according to the weight value for each voxel to the density of the material calculated for each voxel and summing for each surrounding voxel. In the example shown in FIG. 16, for the evaluation value of the sand material, the density of the material for voxel 215 is 1 and the weight value is 0.12, and the density of the material for voxel 217 is 0.56 and the weight value is 0.08. Therefore, 1·0.12 + 0.56·0.08 = 0.1648. Also, for the evaluation value of the grass material, the density of the material for voxel 217 is 0.24 and the weight value is 0.08, and the density of the material for voxel 218 is 0.24 and the weight value is 0.32. Therefore, 0.24·0.08 + 0.24·0.32 = 0.096. Also, for the evaluation value of the soil material, the density of the material for voxel 218 is 0.36 and the weight value is 0.32. Therefore, 0.36·0.32 = 0.1152.

[0106] The game system 1 determines the vertex materials based on the evaluation values for each material. Specifically, a predetermined number of materials are determined as the vertex materials in descending order of the evaluation values. In the present embodiment, two materials with large evaluation values are determined as the vertex materials. In the example shown in FIG. 16, since the evaluation values of the materials of sand, grass, and soil are 0.1648, 0.096, and 0.1152 respectively, the vertex materials are determined as the sand material and the soil material. Further, the game system 1 calculates the ratio of the two determined materials based on the above evaluation values. In the present embodiment, the ratio of the two materials may be expressed as a second material ratio, which is the ratio of the second material to the whole, similar to the above material mixing ratio. In the example shown in FIG. 16, for example, when the first material is the soil material and the second material is set as the sand material, the above second material ratio is represented by 0.1648 / (0.1648 + 0.1152) ≈ 0.59. Note that in other embodiments, as the value representing the ratio of the two materials, a value indicating the ratio of the first material may be used. Also, respective values indicating the ratio of each material may be used.

[0107] In the present embodiment, the game system 1 generates and stores vertex data indicating the position of the vertex, the material IDs of the first and second materials set for the vertex, and the ratio of the materials. However, the method of managing the materials set for the vertex is arbitrary. In other embodiments, the vertex data may be a data structure including data directly indicating the contents of the first and second materials.

[0108] As described above, in this embodiment, for each vertex, with respect to the material IDs included in the voxel data of a plurality of surrounding voxels, a priority parameter (for example, an evaluation value) for each material ID is calculated based on the voxel data. Then, based on the priority parameter, up to a predetermined number (here, two) of material IDs with high priority are selected and determined as the material ID of the vertex. Note that the specific parameter used as the priority parameter is not limited to the above evaluation value. For example, in other embodiments, an evaluation value calculated using the density of the material instead of the above weight value may be used as the priority parameter.

[0109] In this embodiment, an evaluation value, which is an example of the priority parameter, is calculated based on the densities of a plurality of voxels around the vertex such that the priority of the material set in the voxel with a higher density becomes higher (that is, the evaluation value of the material becomes larger and the material is more likely to be selected). According to this, the material of the vertex can be determined by reflecting the magnitude of the density set in the voxel.

[0110] Also, in this embodiment, an evaluation value, which is an example of the priority parameter, is calculated based on the distance from the reference position (specifically, the center position) of a plurality of voxels around the vertex to the vertex such that the priority of the material set in the voxel closer to the vertex becomes higher. According to this, the material of the vertex can be determined by reflecting the distance between the voxel and the vertex.

[0111] Also, in this embodiment, it can be said that an evaluation value, which is an example of the priority parameter, is calculated based on the material mixing ratio of a plurality of voxels around the vertex such that the priority of the material with a higher material mixing ratio becomes higher. According to this, when a plurality of materials are set in one voxel, the material of the vertex can be determined by reflecting the ratio of each material.

[0112] [2-5. Simplification of Vertex] In this embodiment, the game system 1 simplifies each vertex calculated as described above. That is, the game system 1 reduces the number of vertices by grouping some of the vertices calculated as described above and replacing them with a single vertex. Although details will be described later, the coordinates (i.e., positions) and materials of the vertices to be replaced are set based on a plurality of vertices before replacement. By such simplification, the number of vertices and polygons constituting the mesh of the voxel object can be reduced, and the amount of memory used for processing and the processing load can be reduced.

[0113] In this embodiment, the game system 1 simplifies by expressing each vertex using an SVO (Sparse Voxel Octree). FIG. 17 is a diagram showing an example of vertex simplification. In FIG. 17, one square indicated by a solid line shown in FIG. 17(a) represents one vertex division region. Here, the vertex division region is a square region having the center position of the voxel as a vertex (in the actual three-dimensional space, the vertex division region is a cube or a rectangular parallelepiped), and is a region having the dotted lines in FIGS. 15 and 16 described above as sides. Further, in FIG. 17, the vertex division region in which the character "v" is shown inside indicates the vertex division region in which a vertex is set.

[0114] In this embodiment, the game system 1 determines whether or not it is possible to simplify the vertices within a predetermined number (four in FIG. 17, eight in the actual three-dimensional space) of mutually adjacent vertex division regions. When it is determined that simplification is possible, simplification is performed on the vertices within the predetermined number of vertex division regions.

[0115] Fig. 17(a) shows the state before simplification. In the example shown in Fig. 17, it is assumed that the vertex division regions within the range surrounded by the dotted line can be simplified. At this time, the game system 1 simplifies the vertices within each of the above-mentioned predetermined number of vertex division regions that can be simplified so that they are replaced by one vertex (see Fig. 17(b)). As a result, the vertices within the above-mentioned predetermined number of vertex division regions are simplified to one vertex.

[0116] In this embodiment, the game system 1 performs simplification in multiple stages. The number of stages is arbitrary, but in Fig. 17, only the first two stages are illustrated and described. Fig. 17(b) shows the state after the first-stage simplification, and Fig. 17(c) shows the state after the second-stage simplification. In the second-stage simplification, it is determined whether simplification is possible for the vertices generated by the first-stage simplification. In the example shown in Fig. 17, as a result of determining that the vertex division region within the range surrounded by the dotted line in Fig. 17(b) can be simplified, the vertices of the vertex division region are simplified, resulting in the state shown in Fig. 17(c). Note that the determination conditions for whether the first-stage simplification is possible and the determination conditions for whether the second-stage simplification is possible may be the same or different.

[0117] Regarding the determination of whether simplification is possible, the specific method is arbitrary. In this embodiment, as the conditions for the above determination, conditions related to the shape of the voxel object and conditions related to the material are used. In this embodiment, when both the conditions related to the shape of the voxel object and the conditions related to the material are satisfied, it is determined that simplification is possible, and when at least one of the conditions related to the shape of the voxel object and the conditions related to the material is not satisfied, it is determined that simplification is impossible.

[0118] The condition regarding the shape means, for example, that the shape formed by each vertex before simplification and the shape formed by each vertex after simplification are not significantly changed. For example, whether the shape formed by each vertex is not significantly changed before and after simplification can be determined by calculating an index indicating the error between the mesh before simplification and the mesh after simplification, and checking whether the index is less than or equal to a predetermined allowable value. Also, for example, when the shape formed by each vertex before simplification is a hollow shape, but the shape formed by each vertex after simplification is not a hollow shape (that is, the information that it is hollow is lost due to simplification), it is also determined that the condition regarding the shape is not satisfied. Whether the above situation occurs can be determined, for example, based on the density of each voxel corresponding to the vertex division region to be determined. Also, for example, when the shape formed by each vertex before simplification is a shape that can be represented only by two or more vertices and cannot be represented by a single vertex, it is also determined that the condition regarding the shape is not satisfied. Note that, as the condition regarding the shape of the voxel object, the same condition as the conventional method using SVO may be used.

[0119] Also, as a condition regarding materials, in the present embodiment, a condition regarding the number of types of materials set for each vertex within the above-mentioned predetermined number of vertex division regions to be simplified is used. FIG. 18 is a diagram showing an example of the condition regarding materials. FIG. 18(a) shows a case where the materials of vertices 221 to 224 are (grass), (grass), (grass and soil), and (grass and soil), respectively, and FIG. 18(b) shows a case where the materials of vertices 221 to 224 are (grass and sand), (grass), (grass and soil), and (grass and soil), respectively. In the present embodiment, the condition regarding materials is that the total number of types of materials set for each of the above vertices to be simplified is equal to or less than a predetermined number. For example, the condition regarding materials is that it is equal to or less than the number of materials that can be set for one vertex. In the present embodiment, the above-mentioned predetermined number is 2. For example, in the case of FIG. 18(a), the total number of types of materials set for each of the vertices 221 to 224 to be simplified is two types, namely grass and soil, so the condition regarding materials is satisfied. At this time, on the condition that the above-mentioned condition regarding the shape of the object is satisfied, each of the vertices 221 to 224 is determined to be simplifiable. On the other hand, in the case of FIG. 18(b), the total number of types of materials set for each of the vertices 221 to 224 to be simplified is three types, namely grass, soil, and sand, so the condition regarding materials is not satisfied. At this time, regardless of whether the above-mentioned condition regarding the shape of the object is satisfied, each of the vertices 221 to 224 is determined to be non-simplifiable.

[0120] Note that in the game system 1, even if materials that are strictly classified into different types are prepared, and there are a plurality of types of materials with the same set properties but different appearances, for some of such a plurality of types of materials, they may be regarded as the same type in the determination of the condition regarding materials and the determination may be made accordingly. For example, regarding soil materials, there may be a case where a plurality of types of soil materials with the same properties but similar appearances (for example, texture color and pattern) are prepared. In such a case, the game system 1 may regard the plurality of types of soil materials as the same type and make a determination of the condition regarding materials.

[0121] Here, in the present embodiment, with respect to vertices, similar to voxels, up to two types of materials can be set. On the other hand, in the present embodiment, when the total number of types of materials set for each vertex to be simplified is three or more, simplification is not performed. That is, when the total number of types of materials exceeds the number of materials that can be set for one vertex, simplification is not performed. Therefore, even if the number of vertices is reduced by simplification, the information on the materials set for the vertices will not be lost due to simplification, and the material information can be maintained.

[0122] In the present embodiment, the material of the vertex after simplification is determined based on the material of each vertex before simplification. Specifically, the game system 1 sets one or two types of materials set for the vertex before simplification as the first material and the second material for the vertex after simplification. Thereby, the material information can be maintained. Note that the ratio of the materials after simplification is determined based on the ratio of the materials of each vertex before simplification. In the present embodiment, the ratio of the materials after simplification is calculated in the same manner as the method of calculating the ratio of the materials of each vertex using the above evaluation value. That is, the game system 1 calculates a weight value based on the distance between the vertex after simplification and the vertex before simplification, and based on the weight value and the density of the material at the vertex before simplification (note that the evaluation value of the material described in [2-4. Determination of the material of the vertex] above can be used as the density of the material here), calculates the evaluation value for each material. Then, the ratio of the materials is calculated based on the calculated evaluation value for each material.

[0123] [2-6. Generation of Mesh] In this embodiment, based on each vertex simplified as described above, a mesh of the voxel object is generated. FIG. 19 is a diagram showing an example of a mesh generated based on each vertex. Note that the square shown in FIG. 19 indicates the above-described vertex division region, or a vertex division region in which a plurality of vertex division regions are combined into one by simplification. As shown in FIG. 19, the game system 1 generates a mesh composed of polygons having straight lines connecting adjacent vertices of the vertex division region as sides. Each polygon constituting the mesh is a triangle or a quadrilateral.

[0124] In this embodiment, the game system 1 generates two types of meshes: a display mesh and a determination mesh. The display mesh is a mesh used for displaying the voxel object. The determination mesh is a mesh used for collision determination of the voxel object. Although details will be described later, the game system 1 can perform processing using meshes suitable for each of the display and collision determination of the voxel object by using the above two types of meshes.

[0125] In this embodiment, the game system 1 generates the display mesh and the determination mesh based on the data of the above-described SVO (that is, based on each simplified vertex). According to this, by sharing the vertex data used for generating the two types of meshes, the processing efficiency can be improved. Note that in other embodiments, the game system 1 may not perform vertex simplification and may generate the display mesh and / or the determination mesh based on non-simplified vertices.

[0126] In this embodiment, the game system 1 generates the determination mesh to have a simpler shape than the display mesh. Specifically, the game system 1 reduces the number of vertices of the determination mesh compared to the number of vertices of the display mesh. Here, in this embodiment, the SVO data is data that holds the data of the vertices before simplification and the data of the simplified vertices in an octree structure, and also includes the data used for determining whether simplification is possible. This data includes, for example, the data of vertices calculated as candidates for the vertices after simplification (referred to as temporary vertices), and the data of the above-mentioned index indicating the error between the vertices before simplification and the temporary vertices. For example, the game system 1 may use, for the generation of the determination mesh, among the temporary vertices, those vertices for which the above index is equal to or less than a predetermined threshold (this threshold is set to be larger than the above tolerance value). According to this, the number of vertices of the determination mesh can be made less than the number of vertices of the display mesh. By making the number of vertices of the determination mesh less than the number of vertices of the display mesh, the processing load due to collision determination can be reduced. Also, since the number of vertices of the display mesh is not excessively reduced, the appearance of the voxel object can be expressed in detail.

[0127] Note that in other embodiments, the display mesh and the determination mesh may be generated based on the same data or may be generated based on different data. Also, the display mesh and the determination mesh may have the same shape (however, even in this case, the materials set for both may be different). Also, the number of vertices of the determination mesh may be the same as the number of vertices of the display mesh or may be more than the number of vertices of the display mesh.

[0128] [2-6-1. Determination of the Material of the Display Mesh] Next, an example of a method for determining the material and appearance of the display mesh will be described. In the present embodiment, the game system 1 determines the material for each polygon constituting the display mesh. Although details will be described later, in the present embodiment, the polygon corresponding to the above polygon is drawn using up to two textures corresponding to up to two materials. Therefore, the game system 1 ensures that for each polygon constituting the mesh, ultimately, the number of materials set for one polygon is two or less. In other embodiments, three or more materials may be set. For example, in embodiments where there are three or more materials for voxels and vertices respectively, the same number of materials may be set for the polygon.

[0129] In the present embodiment, a quadrilateral may be formed as the polygon constituting the display mesh (see FIG. 19). When determining the material of the display mesh, the game system 1 first divides the quadrilateral constituting the display mesh into two triangles under certain conditions. Hereinafter, with reference to FIG. 20, the process of dividing the quadrilateral into two triangles will be described.

[0130] FIG. 20 is a diagram showing an example in which a quadrilateral constituting a mesh is divided into two triangles. (a) shown in FIG. 20 shows the quadrilateral before division formed by vertices 231 to 234 which are part of the vertices of the mesh, and (b) shown in FIG. 20 shows the two triangles obtained by dividing the quadrilateral. In the example shown in FIG. 20, assume that the materials of each of the vertices 231 to 234 are grass, soil, sand, grass, and grass respectively.

[0131] In this embodiment, when there are three or more types of materials set at each vertex of a quadrilateral in total, the game system 1 determines whether the division condition is satisfied. In this embodiment, the division condition is that by dividing the quadrilateral into two triangles, the total number of types of materials set at each vertex of the triangles can be made two or less. When the division condition is satisfied, the game system 1 divides the quadrilateral into two triangles such that the total number of types of materials set at each vertex is two or less. In the example shown in FIG. 20, the materials set at each vertex 231 to 234 forming the quadrilateral are three types: grass, soil, and sand. Also, when the above quadrilateral is divided into a triangle formed by vertices 231, 232, 234 and a triangle formed by vertices 231, 233, 234, the materials set at each vertex of the former triangle are two types: sand and grass, and the materials set at each vertex of the latter triangle are two types: grass and soil (see (b) of FIG. 20). Therefore, for the above quadrilateral, the division condition is satisfied, so the game system 1 divides the quadrilateral into two triangles.

[0132] Note that since there are two ways to divide a quadrilateral into two triangles, when the division condition is satisfied for at least one of the two ways of dividing the triangles, the game system 1 performs the above division in the way that satisfies the division condition. On the other hand, when the division condition is not satisfied for either of the two ways of dividing the triangles, the division is performed in any one of the ways.

[0133] By performing the division as described above, the game system 1 can generate two triangles in which the materials set at each vertex are two or less so as to minimize the omission of information on three or more types of materials set at each vertex of the quadrilateral. Here, as described above, each polygon constituting the mesh is drawn using up to two types of textures. Therefore, by performing the above division, the game system 1 can draw the polygon using two types of textures so as to minimize the omission of information on the materials set at each vertex.

[0134] In this embodiment, the game system 1 sets a polygon corresponding to the polygon after the above-described division. That is, the vertices of the polygon after the above-described division become the vertices of the polygon of the display mesh.

[0135] In this embodiment, for each polygon constituting the display mesh, when there are three or more types of materials set for each vertex of one polygon in total, the game system 1 selects two types of materials to determine the material of the polygon. FIG. 21 is a diagram showing an example of a method for determining the material of a polygon constituting the display mesh. In the example shown in FIG. 21, for vertex 241 of the triangular polygon constituting the display mesh, let the first material be "grass", the second material be "soil", and the material ratio of the first material: the second material be 0.8:0.2. Also, for vertex 242 of the above polygon, let the first material be "grass", the second material be "sand", and the material ratio of the first material: the second material be 0.5:0.5. Further, for vertex 243 of the above polygon, let the first material be "sand", the second material be "soil", and the material ratio of the first material: the second material be 0.7:0.3.

[0136] When there are three or more types of materials set for each vertex of the polygon in total, the game system 1 calculates a determination value for each material. The determination value is calculated as the value obtained by summing up the ratios for each vertex where the material is set. Then, the game system 1 selects two materials in order from the ones with larger determination values as the materials of the polygon. In the example shown in FIG. 21, the determination value of the grass material is 0.8 + 0.5 = 1.3, the determination value of the sand material is 0.5 + 0.7 = 1.2, and the determination value of the soil material is 0.2 + 0.3 = 0.5. Therefore, as the materials of the polygon shown in FIG. 21, the grass and sand materials are selected (see (a) of FIG. 21).

[0137] Incidentally, the specific method for selecting the material of the polygon of the display mesh is arbitrary. In other embodiments, the material of the polygon of the display mesh may be selected by any method based on the information set at the vertices of the polygon. For example, for the material of the polygon of the display mesh, the material with the largest ratio at one vertex is specified for each vertex, and the material with the largest number of times specified for each vertex may be selected as the material of the polygon.

[0138] In this embodiment, the material of the polygon selected as described above is indicated by the materials set at each vertex of the polygon. That is, when the material of the polygon is selected, the game system 1 changes the materials set at each vertex of the polygon (that is, the material IDs included in the vertex data) to the selected material. In the example shown in FIG. 21, for vertices 241 and 243, before the selection of the material of the polygon, the materials of grass and soil, and sand and soil are set respectively (see (a) of FIG. 21). When the materials of grass and sand are selected as the material of the polygon as described above, the materials set at each of vertices 241 and 243 are changed to grass and sand (see (b) of FIG. 21). Incidentally, for vertex 242, since the material set before the selection is the same as the selected material of the polygon, the material is not changed. As described above, when two types of materials are selected as the material of the polygon, the information of the materials of the third type and later set at each vertex of the polygon will be deleted.

[0139] In addition, the game system 1 changes the ratio of the materials set for each vertex in accordance with the change in the materials set for the vertices. For example, for vertex 241, the content is changed from the first material being grass and the second material being soil to the first material being grass and the second material being sand. Here, since the ratio of the sand material is 0, the material ratio is the first material : the second material = 1 : 0. In this way, the above change formally changes the material of each vertex in order to represent the material of the polygon by the materials of each vertex of the polygon.

[0140] According to the above, since the material set for each vertex of one polygon is only the material corresponding to the texture used for the drawing described later, it is possible to facilitate the execution of the drawing process using the texture.

[0141] Note that due to the above change, it may be the case that all the materials for a certain vertex are changed (that is, none of the materials before the change match the materials after the change). Such a case is, for example, when the material set for the vertex before the change is soil and the materials selected as the material of the polygon are grass and sand. In such a case, the ratio of the materials at the vertex may be set based on the ratio of the materials at the other vertices of the polygon. For example, in the above example, if the first material set for one of the other vertices of the triangular polygon is grass and the material ratio is grass : sand = 1 : 0, and the material set for another vertex is sand and the material ratio is sand : grass = 1 : 0, the material ratio at the vertex may be set to grass : sand = 0.5 : 0.5. Also, the game system 1 may determine the ratio of the materials at the vertex in consideration of the distance between the vertex and the other vertices (for example, based on a weight value that increases as the distance gets closer).

[0142] As described above, in the present embodiment, for each polygon, the game system 1 selects up to a predetermined number (here, 2) of the material IDs set for the vertices included in the polygon (that is, the material IDs set for the vertices of the polygon corresponding to the polygon) and determines them as the material ID of the polygon. According to this, the game system 1 can perform the drawing process while reflecting the material set for the vertices in the appearance of the polygon and suppressing the number of textures used.

[0143] In the present embodiment, for all the materials of the vertices constituting the polygon, when the number of the materials is less than or equal to the predetermined number, the game system 1 determines the material as the material of the polygon. When the material exceeds the predetermined number, the game system 1 selects a predetermined number of materials with high priority based on the priority parameter of each vertex (specifically, based on the determination value calculated based on the above-described evaluation value) and determines them as the material of the polygon. Thus, even when more than a predetermined number of materials are set for each vertex in total, the material of the polygon can be set to a predetermined number or less of materials considering the priority.

[0144] As described above, in the present embodiment, the first and second materials set for each vertex of one polygon are changed to be two types of materials set for the polygon. Here, when such a change is made, there may be a discrepancy in the first and second materials set for the vertices shared by two adjacent polygons.

[0145] FIG. 22 is a diagram showing an example of materials set at each vertex of two adjacent polygons. FIG. 22 shows a state (FIG. 20(b)) in which two polygons are formed by the respective vertices 231 to 234 shown in FIG. 20. In the example shown in FIG. 22, since the materials of the first polygon formed by vertices 231, 233, and 234 are determined to be grass and sand, the first and second materials of these vertices should be set to grass and sand, respectively. On the other hand, since the materials of the second polygon formed by vertices 231, 232, and 234 are determined to be grass and soil, the first and second materials of these vertices should be set to grass and soil, respectively. Therefore, in the example shown in FIG. 22, there is a conflict in the materials to be set for vertices 231 and 234 shared by the two polygons.

[0146] Therefore, in the present embodiment, when there is a conflict in the materials to be set for a vertex shared by two polygons, the game system 1 adds another vertex at the same position with respect to the said vertex. FIG. 22(b) is a diagram showing an example of a state in which vertex 231' is added for vertex 231 and vertex 234' is added for vertex 234. In the example of FIG. 22, for vertices 231 and 234, the game system 1 sets the first and second materials as grass and sand according to the materials of the first polygon. Also, for vertices 231' and 234', the game system 1 sets the first and second materials as grass and soil according to the materials of the second polygon. In this way, by formally setting two vertices as the vertices shared by the two polygons (that is, generating two vertex data with the same position but different materials), it is possible to suppress the occurrence of a conflict in the materials set for the vertices.

[0147] The game system 1 generates a display mesh composed of polygons for which vertices and materials are determined as described above. Also, the game system 1 performs drawing of the voxel object by performing drawing of the polygon based on the information of the materials set at each vertex (that is, the first material and the second material).

[0148] Figure 23 is a diagram showing an example of applying a texture to a polygon. In Figure 23, a triangular polygon formed by the vertices 241 to 243 shown in Figure 21 is shown. Note that the materials set for the vertices 241 to 243 are the same as those shown in (b) of Figure 21.

[0149] Regarding the positions of the vertices of the polygon, drawing is performed by mapping that blends the texture of the first material and the texture of the second material set for the vertex at the ratio of the materials set for the vertex (that is, using the ratio as the blend ratio). Note that the textures of the first and second materials used for drawing are the textures indicated by the drawing setting information associated with each material ID associated with the vertex data in the above-described material data (see Figure 12). In the example shown in Figure 23, regarding the position of vertex 241, since the material ratio is grass:sand = 1:0, drawing is performed using only the grass texture. Also, regarding the position of vertex 243, since the first material is sand and the material ratio is sand:grass = 1:0, drawing is performed using only the sand texture. Also, regarding the position of vertex 242, since the first material is grass, the second material is sand, and the material ratio is grass:sand = 0.5:0.5, drawing is performed by blending the grass texture and the sand texture at a blend ratio of 0.5:0.5.

[0150] Also, for positions other than the vertices of the polygon, the game system 1 determines the blend rate by interpolating the blend rates at each vertex. Then, the textures of the two materials set for each vertex are drawn by a mapping that blends based on the interpolated blend rate. Note that the specific method of interpolation is arbitrary. As an example, the blend rate between vertices is linearly interpolated. In FIG. 23, the positions where the ratio of applying the texture of the grass material is high are shown in white, and the positions where the ratio of applying the texture of the sand material is high are shown in black. In the example shown in FIG. 23, the grass texture is applied at vertex 241, the blend ratio of the sand texture increases toward vertex 243, the blend rate of grass and sand becomes 1:1 at the position of vertex 242, and only the sand texture is applied at the position of vertex 243. In this way, by blending and drawing the two textures set for the polygon (that is, set for each vertex of the polygon) at the blend rate according to the ratio of the materials, the appearance at the boundary between different materials in the display mesh can be made natural. As a result, the appearance of the display mesh with multiple types of materials set can be made natural.

[0151] [2-6-2. Determination of the Material of the Mesh for Judgment] Next, an example of a method for determining the material of the mesh for judgment will be described. Although details will be described later, in this embodiment, collision detection of the voxel object is performed using the mesh for judgment, and processing may be executed according to the material of the voxel object for which collision is detected. Therefore, in this embodiment, the material is also determined for the mesh for judgment.

[0152] In this embodiment, the game system 1 sets one type of material for each polygon that constitutes the determination mesh. Specifically, the game system 1 determines the material to be set for a polygon of the determination mesh based on information about the material set at the vertices of the polygon (i.e., information about the first and second materials and the ratio of the materials).

[0153] Fig. 24 is a diagram showing an example of a method for determining the material of polygons that make up a determination mesh. Fig. 24 shows an example of determining the material for a triangular polygon formed by each of the vertices 241 to 243 shown in Fig. 21. The materials set for each of the vertices 241 to 243 are those shown in Fig. 21(a).

[0154] When determining the material of a polygon, the game system 1 calculates a judgment value for each material set at each vertex of the polygon. In this embodiment, the method for calculating the judgment value is the same as the method for calculating the judgment value used to select the material set at the polygon of the display mesh. Note that the specific method for calculating the judgment value is arbitrary. In other embodiments, the judgment value may be calculated by any method based on the information set at the vertices of the polygon of the judgment mesh.

[0155] In the example shown in Fig. 24, the judgment values for each material are the same as in the case shown in Fig. 21, with the grass material judgment value being 1.3, the sand material judgment value being 1.2, and the earth material judgment value being 0.5. Therefore, the grass material is selected as the material for the polygon shown in Fig. 24.

[0156] As described above, in this embodiment, for each polygon, the game system 1 selects up to a predetermined number (here, 1) of the material IDs set for the vertices included in the polygon (that is, the material IDs set for the vertices of the polygon corresponding to the polygon), and determines them as the material ID of the polygon. According to this, the game system 1 can suppress the number of materials set for the determination mesh to a predetermined number or less. Thereby, it is possible to suppress the complication of the processing according to the type of material that is performed according to the result of the collision determination using the determination mesh. Note that the method for determining the material of the polygon of the determination mesh is arbitrary and is not limited to the above. In other embodiments, the material of the polygon of the determination mesh may be determined by any method based on the information set for the vertices of the polygon.

[0157] Also, in this embodiment, for the polygon of the display mesh, up to two types of materials are set, while for the polygon of the determination mesh, one type of material is set. According to this, for the polygon of the display mesh, two types of textures can be used to achieve a natural appearance, and for the determination mesh, it is possible to suppress the complication of the processing that is performed according to the result of the collision determination using the determination mesh. Note that in other embodiments, the types of materials that can be set for the polygons of the display mesh and the determination mesh are arbitrary. The number of materials that can be set for the polygon of the display mesh and the number of materials that can be set for the polygon of the determination mesh may both be plural, may be the same, or may be different.

[0158] In addition, in the present embodiment, the number of types of materials set for one voxel is up to two, and the number of types of materials set for one polygon in the display mesh is up to two. According to this, while suppressing the data amount of the voxel data, the information of the materials set in the voxel data can be reflected in the materials of the display mesh. Further, in the present embodiment, the number of types of materials set for the vertices set based on the voxel data is also up to two (see FIG. 16). According to this, since two types of materials can be set for the vertices generated during the process of obtaining the display mesh from the voxel data, the information of the materials set in the voxel data can be reflected in the display mesh without loss of material information during the process.

[0159] Also, in other embodiments, the game system 1 may set materials differently for vertices used to generate a display mesh and vertices used to generate a determination mesh with respect to vertices set based on voxel data. For example, the game system 1 may set up to two types of materials for vertices used to generate a display mesh as described above, and may set one type of material for vertices used to generate a determination mesh. Then, for the material of the polygon of the display mesh, two types of materials may be set in the same manner as above, and as the material of the polygon of the determination mesh, one type of material may be set based on the one type of material set for each vertex of the polygon. Note that when setting one type of material for vertices used to generate a determination mesh, the material for which the above-described determination value calculated for each material is the largest may be set as the material of the vertex. Also, by the above, as in the present embodiment, the number of types of materials set for one polygon in the display mesh can be up to two, and the number of types of materials set for one polygon in the determination mesh can be one. Therefore, it is possible to reflect the material information set in the voxel data in the display mesh, and it is possible to suppress the complication of the processing performed according to the result of the collision determination using the determination mesh.

[0160] As described above, in the present embodiment, a display mesh and a determination mesh can be set for one voxel object. However, depending on the game situation, it is not necessary to set both the display mesh and the determination mesh for one voxel object at the same time (for example, it is not necessary to set both in the processing in one frame). For example, the determination mesh may be generated in a range where collision determination is performed in the game space, and may not be generated in a range where collision determination is not performed. As an example, the game system 1 may generate a determination mesh for voxel objects within a predetermined range centered on the player character, and may not generate a determination mesh for voxel objects outside the predetermined range, but only generate a display mesh.

[0161] Also, for the display mesh, the game system 1 may store data related to the generated mesh in the memory, and in a frame after the mesh is generated, use the data without re-executing the process of generating the mesh except for the updated range. According to this, the processing load for generating the display mesh can be reduced. Also, for the determination mesh, the data related to the generated mesh may not be stored in the memory, and the mesh may be sequentially generated as needed (for example, every time collision determination needs to be performed). According to this, the memory area used for generating the mesh can be saved.

[0162] In the above, the method of generating each mesh (that is, the display mesh and the determination mesh) based on the changed voxel data when the voxel data is changed from the initial state has been described. Note that the above method can also be used when generating each mesh based on the voxel data in the initial state, for example, at the start of the game. However, each mesh based on the voxel data in the initial state does not necessarily need to be generated based on the voxel data in the initial state at the start of the game, and may be prepared in advance before the game starts.

[0163] [Processing Using a Mesh of 2-7] Next, a processing example using the mesh generated as described above for the voxel object will be described. In the following, it is assumed that terrain objects such as the ground and walls are voxel objects, and a player character performs an action, and as a result of collision detection, an in-game effect occurs. An example of this case will be described.

[0164] FIG. 25 is a diagram showing an example of a game image representing the movement of a player character on a terrain object. In the example shown in FIG. 25, the material for a polygon in a partial region 251 of the determination mesh of the terrain object that is the ground is set to "lava". Note that the material for polygons other than the region 251 in the determination mesh of the terrain object is set to "rock". In the example shown in FIG. 25, the game system 1 performs a collision determination between the terrain object and the player character 201 using the determination mesh. That is, a collision determination is made as to whether or not the determination mesh of the terrain object and a determination area set for the player character (for example, an area of a predetermined shape set based on the position of the player character) are in contact. When a collision is determined between the polygon whose material is lava and the player character 201, as a process for generating an in-game effect, a process of reducing the physical strength of the player character 201 is performed. Also, in the above case, a process of causing the player character 201 to perform a predetermined reaction is performed.

[0165] Note that in the present embodiment, as the property information included in the above-described material data, for the lava material, a property of reducing the physical strength of the contacted player character (for example, a property that the temperature is equal to or higher than a predetermined value) is set. The game system 1 generates an in-game effect (in the above example, a reduction in the physical strength of the player character) based on the property information corresponding to the material set for the polygon in the determination mesh for which a collision has been determined by the collision determination.

[0166] In addition, when a collision between a polygon whose material is rock and the player character 201 is determined, the process of reducing the physical strength of the player character is not executed. Also, based on the collision, the player character 201 is controlled so as not to be able to enter the inside of the polygon. Therefore, the player character can stand on or walk on the above polygon. In this way, in the present embodiment, by setting the material for each polygon, the game system 1 can execute different processes according to which part of the voxel object another object has contacted. Also, the content of the process to be executed can be made according to the type of material. In the present embodiment, since the player character can change the terrain object (for example, deform it or change the material), for example, a part of the terrain object that is lava can be erased or the lava can be changed to another material. Therefore, the player can avoid a decrease in the physical strength of the player character due to contact with lava by changing the terrain object.

[0167] Note that the content of the process executed when a collision between a voxel object and another object is determined is arbitrary. For example, when the other object is a moving object such as a player character or an enemy character, the process may be a process of outputting the footsteps of the object or displaying an effect (for example, an effect representing dust or water splashes) at the contact location. At this time, the game system 1 can vary the footsteps or the effects according to the type of material set for the polygon of the part of the voxel object that has made contact.

[0168] FIG. 26 is a diagram showing an example of a game image representing a state where a player character extracts a fragment object from a terrain object. As shown in FIG. 26, in this embodiment, the player can cause the player character 201 to perform an action (referred to as a "pull-out action") of grasping the terrain object 202 by a predetermined operation input and pulling out and gripping a part thereof as the fragment object 252. The game system 1, as an in-game effect caused by the pull-out action, erases a part of the terrain object 202 and generates a fragment object 252.

[0169] When the pull-out action is performed, the game system 1 specifically executes the following processing. That is, when the player performs an operation input that causes the player character to perform the pull-out action, the game system 1 causes the player character to perform an action of digging forward and grasping, and performs a collision determination. Then, when a collision between the player character performing the pull-out action and the terrain object is determined, an update range 253 is generated based on the position and orientation of the player character. For example, the update range 253 is generated in a predetermined direction (for example, the front) with respect to the player character. Note that the shape and size of the update range may be determined in advance according to the type of action of the player character. Further, the game system 1 decreases the density of the voxels corresponding to the update range 253. Then, by updating the mesh according to the decrease in the voxel density, the terrain object 202 is deformed so that the portion within the update range 253 is erased (see (b) in FIG. 26). In this embodiment, the density of each voxel corresponding to the update range 253 is decreased, but the voxels whose density is to be decreased may be at least a part of the voxels corresponding to the update range 253.

[0170] Also, in the above, it was assumed that the voxel object corresponding to the update range 253 is unconditionally deformed by the extraction action. However, in other embodiments, the deformation of the voxel object corresponding to the update range 253 may be performed on the condition of the amount of damage set for the voxel. For example, instead of unconditionally deforming the voxel object corresponding to the update range 253, the game system 1 may increase the amount of damage set for the voxel corresponding to the update range 253, and decrease the density in the voxel when the amount of damage exceeds a predetermined value. At this time, the increase amount of damage may be determined according to the action performed on the voxel object.

[0171] Also, the game system 1 generates a fragment object 252 representing the portion of the terrain object 202 that has been erased. That is, the game system 1 generates the fragment object 252 while having the player character hold it based on the above extraction action. The fragment object 252 may be generated to have a shape corresponding to the portion of the terrain object 202 that has been erased, or may have a predetermined shape. The fragment object 252 may be a voxel object or may not be a voxel object. When the fragment object is a voxel object, a voxel space different from the voxel space of the voxels corresponding to the terrain object 202 or the like is defined for the fragment object 252.

[0172] The game system 1 determines the material of the above-mentioned fragment object 252. The material of the fragment object 252 is determined based on the material set for the polygons within the determination mesh that contacts the update range 253 among the determination meshes of the terrain object 202. The material of the fragment object 252 is determined to be the same as any one of the materials set for the polygons within the determination mesh that contacts the update range 253. According to this, the material of the fragment object 252 can be made the same as the material of the erased part of the terrain object. As is clear from the above description, the fragment object 252 is not actually a part of the terrain object. However, by being generated along with the erasure of a part of the terrain object and having the material of the erased part of the terrain object inherited by the fragment object 252, it is possible to give the player an impression as if the player character 201 has taken out a part of the terrain object 202 by a pulling-out action.

[0173] In this embodiment, a priority is set for each type of material to be prepared, and the game system 1 determines the material with the highest priority among the materials set for each polygon of the determination mesh within the update range 253 as the material of the fragment object 252. Here, for example, consider a case where the determination mesh within the update range 253 includes a polygon with a material of rock and a polygon with a material of lava. In such a case, if the material of the fragment object 252 is set to lava, there is a possibility that the player character's physical strength will decrease when the player character grips the fragment object 252 by the pulling action (it is assumed that, as also described in FIG. 25, the material of lava is set to have the property of decreasing the player character's physical strength when contacted). Also, as described above, when the determination mesh within the update range 253 includes polygons with different types of materials set, it is also conceivable that it is difficult for the player to predict what the material of the fragment object 252 will be, and it is also conceivable that the above-mentioned inconvenience will occur contrary to the player's intention. On the other hand, in this embodiment, by setting a priority for the material set as the material of the fragment object, the possibility of the above-mentioned inconvenience occurring can be reduced.

[0174] FIG. 27 is a diagram showing an example of a game image representing a state in which a fragment object is generated when a player character destroys a terrain object. As shown in FIG. 27, in the present embodiment, the player can cause the player character 201 to perform a punch action by a predetermined operation input. Further, as an action in the game caused by the punch action, the game system 1 erases a part of the terrain object 202 and generates a fragment object 255, as in the case of the above punch action. Specifically, the terrain object 202 is deformed as if a part thereof has been erased. Note that, when a punch action is performed, unlike the above-described extraction action, after the punch action, the fragment object 255 is not held by the player character 201 but is arranged around the position where the punch action is performed (see (b) of FIG. 27). Note that the fragments corresponding to the destruction of the terrain object 202 may not be generated in some cases.

[0175] When a punch action is performed, the game system 1 specifically executes the following processing. That is, when a player performs an operation input to cause a punch action on the player character, the game system 1 causes the player character to perform an action of punching forward and performs a collision determination. Then, when a collision between the player character performing the punch action and the terrain object is determined, an update range 254 is generated based on the position and orientation of the player character. For example, the update range 254 is generated in a predetermined direction (e.g., forward) with respect to the player character. Note that the position, shape, and size of the update range 254 due to the punch action may be the same as or different from those of the update range 253 due to the extraction action. Then, the game system 1 decreases the density of the voxels corresponding to the update range 254. As a result, similar to the extraction action, the terrain object 202 is deformed such that the portion within the update range 254 is erased by the punch action (see (b) in FIG. 27). Note that, similar to the extraction action, for the punch action, instead of unconditionally deforming the voxel object corresponding to the update range 254, the game system 1 may increase the amount of damage set for the voxels within the update range 254 according to the punch action, and decrease the density of the voxels when the amount of damage exceeds a predetermined value. Also, the voxels whose density is decreased by the punch action may be at least some of the voxels corresponding to the update range 254.

[0176] In addition, the game system 1 generates a fragment object 255 corresponding to the portion of the terrain object 202 that has been erased. That is, the game system 1 generates the fragment object 255 without giving it to the player character based on the above punch action (for example, in a state where it is arranged around the position where the punch action was performed). The fragment object 255 may be generated so as to have a shape corresponding to the portion of the terrain object 202 that has been erased, or may have a predetermined shape. The fragment object 255 may be a voxel object or may not be a voxel object.

[0177] The game system 1 determines the material of the above fragment object 255. The material of the fragment object 255 is determined based on the material set for the polygon in the determination mesh that contacts the update range 254 among the determination meshes of the terrain object 202. The material of the fragment object 255 is determined to be the same as any one of the materials set for the polygons in the determination mesh that contacts the update range 254. According to this, the material of the fragment object 255 can be made the same as the material of the erased portion of the terrain object. In addition, when the fragment object 255 is generated along with the partial erasure of the terrain object, and the material of the erased portion of the terrain object is inherited by the fragment object 255, it is possible to give the player an impression that a part of the terrain object destroyed by the punch action of the player character has occurred as a fragment object.

[0178] In the present embodiment, the material of the fragment object 255 is determined to be the material with the largest degree of decrease in density in the voxel among the materials set for the polygons in the determination mesh that contacts the update range 254. According to this, it is possible to generate a fragment object that more accurately reflects the material composition of the portion of the terrain object erased by the punch action.

[0179] The method for determining the material of the fragment object generated by the above-described extraction action or punch action is arbitrary. For example, the method for determining the material of the fragment object may be the same for the extraction action and the punch action. Also, for example, among the materials set for each polygon of the determination mesh within the update range, the material set for the most polygons may be determined as the material of the fragment object. Also, for example, among the polygons of the determination mesh within the update range, the material set for a polygon that satisfies a predetermined condition (for example, a polygon at a position in contact with the hand of the player character that performs the extraction action or punch action) may be determined as the material of the fragment object. Also, in other embodiments, a plurality of types of materials may be set for the fragment object.

[0180] In the present embodiment, the player can cause the player character to perform an action of throwing the fragment object 252 or 255 generated as described above (hereinafter referred to as "throwing action"). Note that the player can cause the player character to perform an action of holding a fragment object that is generated in response to a punch action and placed on the ground by a predetermined operation input. By the above-described extraction action or the action of holding the fragment object after the above-described punch action, the player character is in a state of holding the fragment object. In this state, the game system 1 causes the player character to perform an action of releasing the held fragment object in a predetermined direction as a throwing action according to an operation input by the player.

[0181] FIG. 28 is a diagram showing an example of a game image in a scene where a throwing action by a player character is possible and the throwing direction is determined in a state of assuming a throwing stance. As shown in FIG. 28, in a state where the player character 201 has the fragment object 261, the player character 201 can perform a throwing action. In this state, as shown in FIG. 28, the game system 1, as a process for generating an action in the game, displays a aiming image 262 and an object information image 263 over an image showing the game space.

[0182] The aiming image 262 indicates the direction in which the fragment object is released by the throwing action (also referred to as the aiming direction). That is, in response to an operation input by the player to perform a throwing action, the game system 1 moves the fragment object 261 from the position of the player character 201 toward the position in the virtual space indicated by the aiming image 262. Note that the aiming direction is controlled based on the operation input by the player. For example, the game system 1 may change the aiming direction in response to an operation input for changing the direction of the virtual camera. Specifically, the game system 1 controls the virtual camera in response to an operation input so as to rotate and move around the player character while maintaining the state where the player character is included in the field of view, and controls the aiming direction so as to be in the direction corresponding to the line-of-sight direction of the virtual camera. At this time, an aiming image 262 is displayed indicating the position where a straight line extending in the aiming direction from the position of the player character intersects the terrain object 253. Specifically, the game system 1 performs a collision determination between the aiming direction (that is, the above straight line extending in the aiming direction) and the determination mesh of the terrain object 253, and when a collision is determined, the aiming image 262 is displayed. The aiming image 262 is arranged so as to indicate the position of the polygon that intersects the above straight line extending in the aiming direction among the determination meshes.

[0183] When the player character performs a throwing action using the aiming image 262 described above, the player can be presented with the position where the fragment object contacts the voxel object. This makes it easier for the player to perform the throwing action. Note that the specific control method for the aiming direction and the aiming image 262 is arbitrary, and a conventional method may be used. For example, in other embodiments, when the aiming image 262 is displayed, the aiming image 262 may be displayed in a first-person perspective game image where the player character is not displayed.

[0184] In a state where the player character is in a position to throw a fragment object, in response to a predetermined operation input by the player, a throwing action of throwing the fragment object in the aiming direction is performed.

[0185] The object information image 263 shows information about the terrain object 253 at the position indicated by the aiming image 262. In the present embodiment, the object information image 263 shows the name of the material (rock in the example shown in FIG. 28) set for the polygon of the determination mesh at the position indicated by the aiming image 262. This allows the player to be presented with the material of the voxel object that the fragment object released by the throwing action contacts. Also, the object information image 263 shows information about the nature of the material (here, hardness). This allows the player to be presented with the nature of the voxel object that the fragment object released by the throwing action contacts. Note that the content shown by the object information image 263 is arbitrary. For example, in other embodiments, the object information image 263 may show any property related to the material set for the polygon at the position indicated by the aiming image 262, or may show the state of the polygon (for example, the amount of damage described above). In the present embodiment, since there is one type of material for the polygon of the determination mesh, the material corresponding to the aiming position is specified to one. Therefore, it is suitable for displaying information about the material.

[0186] In this embodiment, in response to the determination that the fragment object released by the throwing action has come into contact with the voxel object as a result of the collision determination, the game system 1 makes a change to the voxel object as an action within the game. FIG. 29 is a diagram showing an example of a game image after the terrain object 253 shown in FIG. 28 has been changed due to the contact of the fragment object 261 with the terrain object 253. In the example shown in FIG. 29, the terrain object 253 is deformed so as to have a shape as if the fragment object is attached to the contact position between the fragment object and the terrain object 253. Specifically, the game system 1 generates an update range so as to include the contact position, and deforms the terrain object 253 into the above shape by increasing the density of the voxels in the update range. For example, the update range may be set to a shape corresponding to the shape of the fragment object, and the terrain object 253 may be deformed so that the inside of the update range is within the terrain object 253. As described above, in the example shown in FIG. 29, the shape is such that the additional part 265 is added to the terrain object before deformation. In the example shown in FIG. 29, the fragment object is deleted in response to coming into contact with the terrain object 253.

[0187] Also, the material of the polygon in the additional part 265 is determined based on the material of the fragment object that has come into contact with the terrain object 253. Specifically, the game system 1 sets the material of the voxels within the update range to be the material of the fragment object. Then, the materials of the display mesh and the determination mesh are determined based on the material of the voxels. According to this, since the appearance of the attached additional part 265 can be made the same as the appearance of the fragment object, (although in reality, the terrain object 253 is deformed as described above), it becomes easier for the player to get the impression that the fragment object is attached to the terrain object 253.

[0188] In the example shown in FIG. 29, the change applied to the voxel object in response to the fragment object contacting the voxel object was a transformation that added an additional part to the voxel object, but the change applied to the voxel object is not limited to this. The above change may be one that changes the density of the voxel, or one that changes the material. For example, if the fragment object has the property of exploding, the fragment object may explode in response to contacting the voxel object, and at this time, the voxel object may be deformed as if a part of the voxel object has been erased. Specifically, the game system 1 sets an update range to include the contact position and decreases the density of the voxels within the update range. Also, for example, when the material of the voxel object is lava and the material of the fragment object is ice, the material of the voxel object may be changed in response to the fragment object contacting it. Specifically, the game system 1 sets an update range including the contact position and may change the material that is lava among the materials of the voxels within the update range to obsidian or rock. According to this, it is possible to represent a situation where a lava object is cooled by an ice object and becomes obsidian or rock.

[0189] The content of the above change may be determined based on the material of the voxel object, based on the material of the fragment object, or based on a combination of the material of the voxel object and the material of the fragment object. According to this, various changes can be caused to the voxel object.

[0190] Further, the game system 1 may determine whether to perform the above-described change based on the material of the voxel object, based on the material of the fragment object, or based on a combination of the material of the voxel object and the material of the fragment object. For example, when a fragment object with a material of rock contacts a voxel object with a material of rock, the game system 1 performs the change as shown in FIG. 29, while when a fragment object with a material of rock contacts a voxel object with a material of iron, the game system 1 may not perform the change as shown in FIG. 29.

[0191] In the present embodiment, as described above, one type of material is set for the polygon of the determination mesh and the fragment object. Here, if multiple types of materials are set for at least either the polygon of the determination mesh or the fragment object, it becomes difficult to determine the content of the change added to the voxel object according to the types of the materials of both when the determination mesh and the fragment object are in contact. On the other hand, in the present embodiment, since the materials of the determination mesh and the fragment object determined to be in contact by the collision determination are each one type, it becomes easy to determine the content of the change added to the voxel object.

[0192] [2-8. Material Change] In the present embodiment, the game system 1 executes a process of changing the material of the voxel object during the game. In the present embodiment, by changing the material set for the voxel, the material of the voxel object is changed. Hereinafter, the material change process will be described using the first example to the third example.

[0193] (First Example) As a first example, an example of changing the material according to the deformation such that a part of the tree object is destroyed will be described. FIG. 30 is a diagram showing an example in which the material of the tree object is changed. Note that the tree object 271, which is the voxel object to be processed for the change, may be a voxel object defined in the above-described sub-voxel space or a voxel object defined in the main voxel space.

[0194] In the example shown in FIG. 30, in response to the player character 201 performing a punch action on the tree object 271 (see (a) of FIG. 30), the tree object 271 is deformed such that a part of it is destroyed (see (b) of FIG. 30). At this time, in the first example, the range of the deformed part and its surrounding part of the tree object 271 is changed to look like the inside of the tree (see (b) of FIG. 30). In this way, in the first example, an expression is made such that it looks as if a part of the tree is destroyed and the inside is exposed. Hereinafter, the details of the change process in the first example will be described.

[0195] In the first example, assume that the material set for the voxels related to the tree object 271 before the change process is the material of the tree bark. Also, in the material data, assume that the material ID indicating the material of the tree bark is associated with the material ID indicating the material inside the tree as the internal material ID. Further, in the material data, the material ID indicating the material of the tree bark is set with the ID of the texture representing the tree bark (for example, a texture representing the pattern of the bark in dark brown) as the drawing setting information, and the material ID of the material representing the inside of the tree is set with the ID of the texture representing the inside of the tree (for example, a texture representing the pattern of tree rings in light brown) as the drawing setting information. From the above, as a result of setting the material of the tree bark for each polygon of the tree object 271 before the change process, the tree object 271 has the appearance representing the bark on the surface of the tree (see (a) of FIG. 30).

[0196] In the first example, when player character 201 performs a punch action on tree object 271, game system 1 sets a density update range, which is a range for updating the density of voxels, in the same manner as the example shown in FIG. 27. FIG. 31 is a diagram showing an example of the update range set for tree object 271. Note that the shape of density update range 273 is assumed to be spherical in the example of FIG. 31, but it may be any shape. For example, the shape of the density update range set based on the punch action by player character 201 may be a bell-shaped form consisting of a cylinder extending along the direction of the punch action and a hemisphere arranged at the tip of the cylinder. Similar to the example shown in FIG. 27 in the first example as well, the density of the voxels within density update range 273 among the respective voxels related to tree object 271 is updated so as to decrease. For example, the density of the voxels within density update range 273 is updated to a value less than the above-mentioned reference value. By generating the mesh of tree object 271 based on the density of the updated voxels, tree object 271 will be deformed such that the portion within density update range 273 is erased.

[0197] Also, in the first example, game system 1 sets a material update range 274, which is a range for updating the material of voxels. In the present embodiment, similar to density update range 273, material update range 274 is represented by an SDF. In the present embodiment, material update range 274 is set so as to enclose density update range 273 (see FIG. 31). According to this, for the tree object 271 after the change process, the material is changed for the deformed part as if it were destroyed and the surrounding part, so that the tree object 271 can have a more natural appearance.

[0198] In the first example, the game system 1 generates a material update range 274 by expanding the density update range 273. In the example of FIG. 31, the material update range 274 is a sphere with a larger radius than the density update range 273. According to the method of expanding the density update range 273 as described above, the material update range 274 that encloses the density update range 273 can be easily generated. Note that in other embodiments, the material update range does not have to be generated based on the density update range and may be included in the game program in advance in the same way as the density update range. Also, in the first example, the center position of the material update range 274 is set to the same position as the center position of the density update range 273. However, the material update range 274 may be set at any position that encloses the density update range 273. Also, the shape of the material update range 274 is arbitrary. In other embodiments, the material update range 274 and the density update range 273 do not have to be similar shapes.

[0199] The game system 1 changes the material of the voxels within the material update range 274 among the voxels related to the tree object 271. In the first example, the material of the voxels within the material update range 274 is changed to the material indicated by the internal material ID associated with the ID of the material before the change in the above-described material data (see FIG. 12). As described above, the material ID representing the outer bark of the tree is associated with the material ID representing the inside of the tree as the internal material ID. Therefore, in the first example, the material of the voxels within the material update range 274 is changed from the material of the outer bark of the tree to the material of the inside of the tree by the change process. Specifically, the game system 1 updates the material ID indicated by the voxel data for the voxels within the material update range 274 so as to indicate the internal material ID, thereby changing the material set for the voxels to the internal material.

[0200] Note that, as described above, in the present embodiment, voxel data holds up to a plurality (specifically, two) of material IDs per voxel. In the first example, it is assumed that one type of material is set for the voxel. However, when a plurality of types of materials are set for the voxel, in the material change process, each material ID set for each voxel within the material update range is changed to the corresponding internal material ID. For example, when a rock material and a soil material are set for the voxels within the material update range, the materials after the change for the voxels are the internal materials associated with the rock material and the internal materials associated with the soil material. According to this, when a plurality of types of materials are set for the voxel, it is possible to reduce the possibility of inconvenience such that, for example, when only one type of material is changed, the appearance of the voxel object after the change becomes unnatural.

[0201] When the change process is performed, the game system 1 generates the mesh of the tree object 271 (specifically, the display mesh and the determination mesh) according to the methods described in [2-4. Determination of the Material of the Vertex] to [2-6. Generation of the Mesh] based on the density and material of the voxel after the change process. As a result, the tree object 271 is deformed as if a part of it is destroyed, and the materials of the polygons of the deformed part and the surrounding parts are set to the internal material of the tree. When the tree object 271 is drawn, the above polygons are drawn using a texture representing the inside of the tree. As a result, the tree object 271 after the change process has an appearance in which the deformed part and the surrounding parts represent the inside of the tree, and as a whole, it can perform an expression as if a part of it is destroyed and the inside is exposed.

[0202] As described above, in the first example, in response to the voxel object being deformed as if it were destroyed, by changing the material of the mesh in the deformed part to the material representing the inside, it is possible to create an expression as if a part of the voxel object is destroyed and the inside is exposed. As a method of expressing the appearance as if a part of the voxel object is destroyed and the inside is exposed, it is also conceivable to set the material representing the outer shell of the object for the voxels located on the surface of the mesh of the voxel object representing a certain object, and set the material representing the inside of the object for the voxels located in the inner region of the mesh of the voxel object. In this method, when the voxels located in the inner region of the mesh of the voxel object are deformed so as to be located on the surface of the deformed mesh, the voxel object will have an appearance as if the inside is exposed. However, in the above method, the part that looks like the outer shell of the voxel object's mesh becomes thick, and it is difficult to express the part that looks like the outer shell thinly.

[0203] On the other hand, in the first example, by adopting the method of changing the material for the voxels within the material update range that encloses the density update range, not only the deformed part but also the surrounding part of the voxel object will be changed to the appearance representing the inside of the tree. The above-mentioned surrounding part is the part where the mesh is not deformed, but the appearance is changed to represent the inside of the tree. By creating such a part, the tree object after the change process will look as if the thin outer skin of the tree has been peeled off. Thus, according to this embodiment, it is possible to represent the thin outer shell that occurs when the object is destroyed.

[0204] (Second Example) As a second example, an example of changing the material without deforming the mesh of the voxel object will be described. In this embodiment, as shown in the second example, it is also possible to change the appearance of the voxel object by changing the material without changing the density of the voxels.

[0205] FIG. 32 is a diagram showing an example in which part of the material of the terrain object is changed. In the second example, the player character 201 moves on the terrain object 281 while riding on the rock fragment object 282 (see (a) of FIG. 32). Note that the terrain object 281 appears to have grass growing on the ground surface. Here, when the fragment object 282 moves on the terrain object 281, the portion of the terrain object 281 that the fragment object 282 has passed through is changed to the appearance of soil without grass growing (see (b) of FIG. 32). In this way, in the second example, when the fragment object 282 passes over the grassy ground, an expression is performed such that the grassy surface appears to be scraped off and the soil is exposed. Hereinafter, the details of the change process in the second example will be described.

[0206] In the second example, it is assumed that the material set for the voxels related to the terrain object 281 before the change process is the grass material. Also, in the material data, it is assumed that the material ID indicating the grass material is associated with the material ID indicating the soil material as the internal material ID. From the above, as a result of setting the grass material for each polygon of the terrain object 281 before the change process, the surface of the terrain object 281 appears to have grass growing (see (a) of FIG. 32).

[0207] In the second example, the game system 1 sets the material update range based on the fragment object 282. The shape and size of the material update range are arbitrary, but the material update range is, for example, in the shape of a hemisphere or a cylinder extending downward from the lower surface of the fragment object 282. Note that in the second example, the density update range is not set.

[0208] The game system 1 performs a change process of changing the material of the voxels within the material update range based on the fragment object 282 among the voxels related to the terrain object 281 to the internal material. Similar to the first example in the second example as well, the material of the voxels within the material update range is changed to the material indicated by the internal material ID associated with the ID of the material before the change in the above-described material data (see FIG. 12). In the second example, as described above, the material ID of the soil is associated as the internal material ID related to the material ID of the grass. Therefore, in the second example, the material of the voxels within the material update range is changed from the grass material to the soil material. Note that in the second example, since the density update range is not set, the density of each voxel related to the terrain object is not updated.

[0209] When the change process is performed, similar to the first example in the second example as well, the game system 1 generates the mesh of the terrain object 281 according to the method described in [2-4. Determination of the Material of the Vertex] to [2-6. Generation of the Mesh] based on the density and material of the voxels after the change process. As a result, the material of the polygon below the fragment object 282 among the meshes of the terrain object 281 is changed to the soil material. Also, when the above terrain object 281 is drawn, the above polygon is drawn using a texture representing the soil. As a result, the terrain object 281 drawn after the change process looks as if the grass in the part below the fragment object 282 has been cut and the soil is exposed. Also, each time the fragment object 282 moves, since the material of the part below the fragment object 282 among the terrain object 281 is sequentially changed by the above-described process, the terrain object 281 looks as if the grass in the part where the fragment object 282 has moved above it has been cut and the soil is exposed.

[0210] As described above, in the second example, when an event occurs in which the fragment object 282 carrying the player character 201 is placed on the terrain object 281, a material update range is set, and among the voxel data of the terrain object 281, the material of the voxels corresponding to the material update range is changed to the internal material. As a result, the material can be changed without deforming the voxel object. For example, as in the second example, an expression that makes the surface of the voxel object appear to be thinly removed can be achieved without deforming the voxel object.

[0211] In other examples, in the change process of changing the material of the voxels within the material update range to the internal material, the game system 1 may change the material before the change to another material and further change it to the internal material related to the other material. Such a change process involving two changes is used, for example, when a player character rides on a fragment object with an ice material set and moves sliding on a terrain object with a lava material set. In this embodiment, when another object with an ice material set comes into contact with an object with a lava material set, the material of the contacted part among the objects is changed from the lava material to the obsidian outer shell material. Also, in the material data, it is assumed that an internal material ID indicating the material inside the obsidian is associated with the material ID indicating the obsidian outer shell material. In the above case, the game system 1 sets a material update range based on the fragment object in the same manner as in the second example. Then, for the voxels within the material update range among the voxels related to the terrain object, the lava material is changed to the obsidian outer shell material, and further, the obsidian outer shell material is changed to the obsidian internal material.

[0212] According to the above, it is possible to collectively execute the process of changing the material according to the contact of the voxel object with another object and the process of changing the material according to the movement of the fragment object on the terrain object.

[0213] Also, according to the above, the material set for each voxel of the terrain object after the change process can be either one of two types: the material of lava or the material inside obsidian. Here, when the number of types of materials set for a plurality of adjacent voxels is three or more, the material set for the polygon whose vertices are set based on the plurality of voxels becomes two types, resulting in a lack of material information. Therefore, the appearance of the polygon may become unnatural. On the other hand, according to the above change process, the number of types of materials set for each voxel of the terrain object can be set to two types, so the possibility of generating a polygon with an unnatural appearance can be reduced. In other embodiments, in the change process of performing the above two changes, the range of the first change and the range of the second change may be set to different ranges.

[0214] Also, in another example, the change process of performing the above two changes may further include a process of updating the density of the voxels within the density update range.

[0215] (Third Example) As a third example, an example of changing the material of the voxel to a predetermined material different from the internal material associated with the material before the change will be described. As shown in the following third example, the material after being changed by the deformation process may be determined independently of the material before the change.

[0216] FIG. 33 is a diagram showing an example in which the material of a terrain object is changed. In the third example, in response to the player character 201 performing a punch action on the terrain object 291 (see (a) of FIG. 33), the terrain object 291 deforms as if a part of it is destroyed (see (b) of FIG. 33). At this time, in the third example, the range of the deformed part of the terrain object 291 and the surrounding part (range 291a shown in FIG. 33) is changed to look like gold, and further, the surrounding range (range 291b shown in FIG. 33) is changed to look like the interior of a rock (see (b) of FIG. 33). Thus, in the third example, when a part of the terrain object 291 is destroyed, an expression is made such that the surrounding area appears to change to gold or the like. Hereinafter, the details of the change process in the third example will be described.

[0217] In the third example, assume that the material set for the voxels related to the terrain object 291 before the change process is the material of the outer shell of a rock. Also, in the material data, assume that the material ID indicating the material of the outer shell of the rock is associated with the material ID indicating the material inside the rock as the internal material ID. From the above, as a result of the material of the outer shell of the rock being set for each polygon of the terrain object 291 before the change process, the terrain object 291 has the appearance of representing the outer shell of a rock (see (a) of FIG. 33).

[0218] When the player character 201 performs a punch action on the terrain object 291, the game system 1 sets the density update range in the same manner as in the first example and updates the density of the voxels within the update range. Note that the shape and size of the density update range in the third example may be the same as or different from those in the first example.

[0219] Also, in the third example, the game system 1 sets two material update ranges. FIG. 34 is a diagram showing an example of each update range set in the third example. The first material update range 294 indicates a range in which the material of the voxels within the update range is changed to the internal material. Also, the second material update range 295 indicates a range in which the material of the voxels within the update range is changed to a predetermined material (here, the material of gold). Each of the material update ranges 294 and 295 is set so as to enclose the density update range 293. Also, in the present embodiment, the first material update range 294 is set to be larger than the second material update range 295. In the example shown in FIG. 34, the first material update range 294 encloses the second material update range 295. However, in other examples, the first material update range 294 may be set so as not to include a part of the region of the second material update range 295. Also in the third example, similar to the first example, each of the material update ranges 294 and 295 is generated by expanding the density update range 293. Note that the shapes of the respective update ranges 293 to 295 are spherical in the example of FIG. 34, but may be of any shape. Also, the shapes and sizes of the material update ranges 294 and 295 in the third example may be the same as or different from the material update range in the first example.

[0220] The game system 1 changes the material of the voxels within the material update range. Here, in the third example, the material of the voxels within the first material update range 294 is changed to the internal material associated with the material before the change in the same manner as in the first example. As described above, the material ID representing the outer shell of the rock has, as the internal material ID, the material ID representing the inside of the rock associated therewith. Therefore, in the third example, the material of the voxels within the first material update range 294 is changed from the material of the outer shell of the rock to the material of the inside of the rock by the change process.

[0221] In addition, the game system 1 changes the material of the voxels within the second material update range 295 to the material of gold, regardless of the material before the change. Therefore, in the present embodiment, for the voxels within the first material update range 294 and also within the second material update range 295, after being once changed to the internal material, they will be changed to the material of gold. Note that the change of the material based on the two material update ranges may be performed in any method such that, as a result, the material of the voxels within the second material update range 295 becomes the material of gold, and the material of the voxels outside the second material update range 295 and within the first material update range 294 becomes the internal material.

[0222] Also in the third example, in the same manner as in the first example, the mesh of the terrain object 291 is generated based on the voxel data after the change process. Therefore, in the third example, the terrain object 291 drawn after the change process has an appearance as if the surrounding area (area 291a shown in FIG. 33) of the destroyed part has changed to gold.

[0223] In addition, in the third example, since the voxels within the first material update range 294, which is larger than the second material update range 295, are changed to the internal material, the terrain object 291 drawn after the change process has an appearance such that the surrounding area of the destroyed part has changed to gold, and further the surrounding area thereof (area 291b shown in FIG. 33) has an appearance representing the inside of the rock. Note that in other examples, the game system 1 may set only the material update range for changing to a predetermined material independent of the internal material without setting the material update range for changing to the internal material in the change process. For example, in the third example, the game system 1 may set the second material update range 295 without setting the first material update range 294, and change the material of the voxels within the second material update range 295 to the material of gold.

[0224] Note that the change process in the third example is performed on the condition that the player character 201 is in a predetermined state (which can also be said to be a state having the ability to change the area around the destroyed terrain object into gold). When a punch action is performed on the terrain object 291 by a player character 201 that is not in the above - mentioned predetermined state, similar to the first example, the material of the voxels within the material update range is changed to the internal material associated with the material before the change. Specifically, in the above - mentioned case, the game system 1 sets only the first material update range 294 without setting the second material update range 295 in the change process, and changes the material of the voxels within the first material update range 294 to the internal material.

[0225] Note that the condition for the player character 201 to be in the above - mentioned predetermined state is arbitrary. In this embodiment, the player character 201 becomes in the predetermined state when a predetermined condition in the game is satisfied. For example, it may become in the predetermined state when a predetermined parameter regarding the player character reaches a certain value, or when the player character 201 acquires a predetermined item. Also, there are two types of punch actions performed by the player character 201. In the change process corresponding to the first punch action, only the first material update range 294 is set without setting the second material update range 295, and in the change process corresponding to the second punch action, the first and second material update ranges 294 and 295 may be set. At this time, the player character 201 may be able to execute the second punch action when it is in the above - mentioned predetermined state.

[0226] [3. Specific Examples of Processing in the Game System] Next, with reference to FIGS. 35 to 37, a specific example of the information processing in the game system 1 will be described.

[0227] FIG. 35 is a diagram showing an example of various data used for information processing in the game system 1. Each data shown in FIG. 35 is stored in a memory accessible by the main body device 2 (for example, flash memory 84, DRAM 85, and / or a memory card or the like mounted on the slot 23). As shown in FIG. 35, the game system 1 stores a game program. The game program is for executing the game processing in the present embodiment (specifically, the game processing shown in FIG. 36). Note that the game program includes the above-described material data (see FIG. 12). Further, the above memory stores the above-described voxel data (see FIG. 11), update range data, mesh data, object data, etc. (see FIG. 35).

[0228] The update range data is data indicating the above-described update range. In the present embodiment, the update range is represented by the above-described SDF. The update range data includes data indicating the above-described density update range and data indicating the material update range.

[0229] The mesh data includes various data related to the mesh of the voxel object. As shown in FIG. 35, in the present embodiment, the mesh data includes SVO data, display mesh data, and determination mesh data. The SVO data is data that holds each vertex calculated from the voxel data in the above-described SVO structure. Note that in the present embodiment, the SVO data includes, in addition to data indicating the position of each vertex, data indicating the material set for each vertex (for example, data indicating the ID of the material). The display mesh data includes various data related to the display mesh. Specifically, the display mesh data includes data indicating each vertex of the display mesh and data indicating the material set for each vertex (for example, data indicating the ID of the material). The determination mesh data includes various data related to the determination mesh. Specifically, the determination mesh data includes data indicating each vertex of the determination mesh and data indicating the material set for each vertex (for example, data indicating the ID of the material).

[0230] Object data includes various data related to objects other than voxel objects (for example, player characters, fragment objects, etc.). Object data is stored for each object that appears in the game space. Object data includes, for example, data indicating the position, speed, and state of the object.

[0231] FIG. 36 is a flowchart showing an example of the flow of game processing executed by the game system 1. The execution of the game processing is started, for example, in response to the start of the game according to the player's instruction during the execution of the above game program. Note that the processing loop consisting of a series of processes in steps S1 to S13 is executed once per frame cycle.

[0232] In the present embodiment, the processor 81 of the main body device 2 will be described as executing the processing of each step shown in FIG. 36 by executing the above game program stored in the game system 1. However, in other embodiments, some of the processing of each step may be executed by a processor (for example, a dedicated circuit, etc.) different from the processor 81. Further, when the game system 1 can communicate with another information processing device (for example, a server), a part of the processing of each step shown in FIG. 36 may be executed in the other information processing device. Also, the processing of each step shown in FIG. 36 is merely an example, and if the same result can be obtained, the processing order of each step may be changed, or another process may be executed in addition to (or instead of) the processing of each step.

[0233] Further, the processor 81 executes the processing of each step shown in FIG. 36 using a memory (for example, DRAM 85). That is, the processor 81 stores the information (in other words, data) obtained by each processing step in the memory, and when using the information in subsequent processing steps, reads out and uses the information from the memory.

[0234] In step S1 shown in FIG. 36, the processor 81 acquires the operation data indicating the operation input by the player. That is, the processor 81 acquires the operation data received from each controller via the controller communication unit 83 and / or each of the terminals 17 and 21. Next, the process of step S2 is executed after step S1.

[0235] In step S2, the processor 81 designates, as a processing target, any one of the objects in the game space that require processing and for which the processing has not been completed, and executes a process of calculating the speed and a process of reflecting the result of contact between the objects in the previous frame for the designated object. The speed of the object is used to calculate the position of the object in the current frame in the process of step S11 described later. For example, when the designated object is the player character, the speed of the player character is calculated based on the operation data acquired in step S1. Also, when the designated object is an object not operated by the player (for example, a fragment object), the speed of the object is calculated based on a rule predetermined in the game program. For example, the speed of the fragment object is set to 0 when it is placed on the terrain object and not moving, is set to the same as the speed of the player character when it is held by the player character, and is set to the speed of moving in the above-mentioned aiming direction with the magnitude determined by the above rule when it is released by a throwing action by the player character. Specifically, the speed of the object is calculated based on virtual physical calculations including the interaction between the objects. For example, interactions such as repulsion due to collision between objects, friction due to contact, falling due to virtual gravity, and deceleration due to virtual air resistance are reflected in the speed determination.

[0236] In addition, the process of reflecting the result of contact between objects in the previous frame includes a process of applying the influence of contact to the object when it is determined in the collision determination (step S10) in the previous frame that the objects are in contact with each other. The above process is, for example, the following process. · When it is determined that the player character has come into contact with the lava terrain object in the previous frame, a process of reducing the physical strength of the player character · When it is determined that the player character has come into contact with the terrain object by a pulling action or a punching action in the previous frame, a process of generating a fragment object · When it is determined that the fragment object has come into contact with the rock terrain object in the previous frame, a process of disappearing the fragment object When the state regarding the object is changed in the process of step S2 above, the processor 81 updates the object data stored in the memory regarding the object so as to indicate the changed content. The process of step S3 is executed after step S2.

[0237] In step S3, the processor 81 determines whether an update event that updates the voxel object has occurred due to the object specified in step S2. For example, the determination in step S3 is made based on the result of the collision determination (step S10) in the previous frame. For example, if it is determined that the player character has contacted the terrain object by a pulling action or a punching action in the previous frame, it is determined that an update event has occurred in which a part of the terrain object is deformed as if it has been erased (see FIGS. 26 and 27). Note that such an update event includes an event in which a part of the terrain object is deformed as if it has been erased and the material for the range of the deformed part and its surrounding parts is changed (see FIGS. 30 and 33). Also, for example, if it is determined that the fragment object has contacted the rock terrain object in the previous frame, it is determined that an update event has occurred in which the terrain object is deformed as if the fragment object has adhered to the terrain object (see FIG. 29). Also, for example, if it is determined that the fragment object on which the player character has ridden is placed on the terrain object, it is determined that an update event has occurred in which the material of a part of the terrain object is changed (see FIG. 32). If the determination result in step S3 is affirmative, the process of step S4 is executed. On the other hand, if the determination result in step S3 is negative, the process of step S5 is executed.

[0238] In step S4, the processor 81 executes a voxel update process for updating the voxel data regarding the voxel object for which it is determined in step S3 that an update event has occurred. Hereinafter, with reference to FIG. 37, the details of the voxel update process in step S4 will be described.

[0239] Figure 37 is a sub flowchart showing an example of the detailed flow of the voxel update process in step S4 shown in Figure 36. In the voxel update process, first in step S21, the processor 81 determines whether the update event determined to have occurred in step S3 is an event for deforming the voxel object. The determination in step S21 is made based on the type of the update event. For example, for the update events shown in FIGS. 26, 27, 29, 30, and 33 described above, it is determined that they are events for deforming the voxel object. On the other hand, for the update event shown in FIG. 32, it is determined that it is an event that does not deform the voxel object. If the determination result in step S21 is affirmative, the process of step S22 is executed. On the other hand, if the determination result in step S21 is negative, the process of step S24 is executed.

[0240] In step S22, the processor 81 sets a density update range for updating the density of the voxels related to the voxel object in the game space. For example, the specific content of the density update range (that is, position, shape, and size) is associated with each type of update event in the game program. The density update range set in step S22 is set so as to be associated with the content related to the type of update event determined to have occurred in step S3. The processor 81 stores the data indicating the set density update range in the memory as update range data. The process of step S23 is executed after step S22.

[0241] In step S23, the processor 81 changes the density of the voxels corresponding to the density update range set in step S22 according to the update event. For example, when the voxel object is deformed so as to be erased (also referred to as destroyed), a change is made to decrease the density of the voxels within the density update range. Also for example, when the voxel object is deformed so that the volume of the inner region increases, a change is made to increase the density of the voxels within the density update range. Specifically, the processor 81 updates the voxel data stored in the memory so as to change the density of the voxels corresponding to the density update range (see the above [2-2. Update of Voxel Data] and [2-8. Change of Material]). The process of step S24 is executed after step S23.

[0242] In step S24, the processor 81 determines whether the update event determined to have occurred in step S3 is an event that changes the material of the voxel object. The determination in step S24 is made based on the type of the update event. For example, for the examples of the update events shown in FIGS. 30, 32, and 33 described above, it is determined that the event is one that changes the material of the voxel object. On the other hand, for the examples of the update events shown in FIGS. 26, 27, and 29, it is determined that the event is one that does not change the material of the voxel object. If the determination result in step S24 is affirmative, the process of step S25 is executed. On the other hand, if the determination result in step S24 is negative, the processor 81 ends the voxel update process.

[0243] In step S25, the processor 81 sets a material update range for changing the material of the voxels related to the voxel object in the game space. For example, when the density update range is set by the process of step S22, the material update range is generated based on the density update range (see (the first example) and (the third example) of the above [2-8. Change of material]). Further, the specific content of the material update range for which the corresponding density update range is not set (that is, the position, shape, and size) is associated, for example, for each type of update event in the game program. When the process of step S22 is not executed, the material update range is set to be the content associated with the type of update event determined to occur in step S3. Note that, as described in (the third example) of the above [2-8. Change of material], a plurality of material update ranges corresponding to one density update range may be set. The processor 81 stores data indicating the set material update range in the memory as update range data. The process of step S26 is executed after step S25.

[0244] In step S26, the processor 81 changes the material of the voxels corresponding to the material update range set in step S25 according to the update event. For example, the processor 81 changes the material of the voxels corresponding to the material update range to the internal material associated with the material before the change, or changes it to a predetermined material. When a plurality of material update ranges are set in step S25, in step S26, the materials of the voxels within each material update range are changed. For example, in the case of (the third example) of the above [2-8. Material change], after the material of the voxels within the first material update range is changed to the internal material, further, the material of the voxels within the second material update range is changed to the material of gold. The processor 81 updates the voxel data stored in the memory so as to change the material of the voxels corresponding to the material update range (see the above [2-2. Update of voxel data] and [2-8. Material change]). After step S26, the processor 81 ends the voxel update process.

[0245] Returning to the description of FIG. 36, in step S5 following the voxel update process of step S4, the processor 81 determines whether the processing of the above steps S2 to S4 has been completed for all objects that require processing. If the determination result in step S5 is affirmative, the processing in step S6 is executed. On the other hand, if the determination result in step S5 is negative, the processing in step S2 is executed again.

[0246] In step S6, the processor 81 updates the vertices of the voxel objects in the game space. That is, when the voxel data is updated in the processing of step S5, new vertices are calculated based on the updated voxel data. The position of the new vertices is calculated according to the method described in the above [2-3. Calculation of vertices]. Also, the material of the new vertices is calculated according to the method described in the above [2-4. Determination of vertex material]. The processing in step S7 is executed next to step S6.

[0247] In step S7, the processor 81 simplifies the vertices. That is, for each vertex updated by the process of step S6, the processor 81 performs simplification according to the method described in the above [2-5. Vertex Simplification]. The SVO data stored in the memory is updated to indicate each vertex obtained by the processes of steps S6 and S7 above. Therefore, the SVO data is updated by the processes of steps S6 and S7. Note that the processes of steps S6 and S7 do not need to recalculate the vertices for the entire voxel data, and may be executed only for the portion where the content of the voxel is changed in the process of step S5. The process of step S8 is executed after step S7.

[0248] In step S8, the processor 81 updates the display mesh of the voxel object based on the SVO data stored in the memory. Note that the position of each vertex of the display mesh and the material of each polygon of the display mesh (that is, the material set for each vertex of the polygon) are calculated according to the methods described in the above [2-6. Mesh Generation] and [2-6-1. Determination of the Material of the Display Mesh]. The processor 81 updates the display mesh data stored in the memory to indicate the position and material of each vertex of the updated display mesh. The process of step S9 is executed after step S8. Note that the processor 81 may start the processes after step S9 and execute them in parallel without waiting for the completion of step S8. In that case, step S8 needs to be completed before the start of step S12.

[0249] In step S9, the processor 81 updates the determination mesh of the voxel object based on the SVO data stored in the memory. Note that the position of each vertex of the determination mesh and the material of each polygon of the determination mesh (that is, the material set for each vertex of the polygon) are calculated according to the methods described in the above [2-6. Generation of Mesh] and [2-6-2. Determination of Material of Determination Mesh]. The processor 81 updates the determination mesh data stored in the memory so as to indicate the positions and materials of the vertices of the updated determination mesh. The process of step S10 is executed after step S9.

[0250] Note that in the example shown in FIG. 36, the generation process of the determination mesh (step S9) is executed every frame. However, the generation process of the determination mesh does not necessarily have to be executed every frame. For example, when the collision determination process of step S10 is executed only in frames that satisfy a predetermined condition, the processor 81 may execute the generation process of the determination mesh in the frames in which the collision determination of step S10 is performed. Further, the processor 81 may execute the generation process of the determination mesh for the voxels within the area in the game space where the collision determination of step S10 is performed. For example, in a situation where there are no objects to be collided with other than voxel objects around the player character in the game space (that is, a situation where only the collision determination between the player character and the surrounding voxel objects needs to be performed), the processor 81 may execute the generation process of the determination mesh for the voxels within a predetermined range based on the player character.

[0251] In step S10, the processor 81 performs collision determination for each object in the game space based on the determination mesh data and object data stored in the memory. That is, for the voxel object, the processor 81 uses the determination mesh, and for an object that is not a voxel object, the processor 81 uses a determination region with a predetermined shape set for the object to perform collision determination. In this embodiment, the collision determination in step S10 is performed in consideration of the speed calculated in step S2 above. That is, the processor 81 performs collision determination using the position when moving at the above speed as the position of each object.

[0252] In this embodiment, the presence or absence of the following contacts, for example, is determined by the collision determination in step S10. · Contact between the player character performing a movement, punch action, or pull-out action and the terrain object · Contact between the character performing the action of lifting (the fragment object) and the fragment object · Contact between the straight line extending in the aiming direction from the position of the player character and the terrain object · Contact between the fragment object released by the throwing action of the player character and the terrain object Note that when it is determined in the collision determination in step S10 that the objects are in contact with each other, in the process of step S2 in the next frame, a process reflecting the result of the contact between the objects is executed, or in the process of step S3 in the next frame, it is determined that an update event has occurred. The process of step S11 is executed after step S10.

[0253] In step S11, the processor 81 controls the operations of each object in the game space. For example, regarding the player character, the processor 81 performs control to cause the player character to move and perform various actions based on the operation data acquired in step S1. When a predetermined action occurs, an area for collision determination corresponding to the action is generated within the game space. Also, for example, the fragment object is controlled to move in the above-described aiming direction in response to being thrown by the player character. In one execution of the process of step S11, the processor 81 controls each object so as to advance the operation for one frame regarding operations (for example, actions by the player character) performed over a plurality of frames. By repeatedly executing the process of step S11 over a plurality of frames, each object performs a series of operations related to movement and various actions. Also, the position of the object is basically determined to be the position after moving at the speed calculated in step S2 above. However, if it is determined by the collision determination in step S10 that the object contacts another object and the movement is obstructed by the contacted other object, the position of the object is determined not to change. The object data stored in the memory is updated to indicate the object after the control in step S11. The process of step S12 is executed after step S11.

[0254] In step S12, the processor 81 generates a game image. That is, the processor 81 generates a game image by performing drawing based on a virtual camera for each polygon of the display mesh of the voxel object and each polygon of the object other than the voxel object. Note that each polygon of the display mesh is drawn using drawing settings such as a texture corresponding to the material set for the polygon according to the method described in the above [2-6-1. Determination of the material of the display mesh]. Further, in the present embodiment, when the player character is in a state where a throwing action is possible, the processor 81 generates a game image including the above-described aiming image and object information image (see FIG. 28). The game image generated in step S12 is output to the display device and displayed at a cycle of once per frame.

[0255] In step S13, the processor 81 determines whether to end the game. For example, when a predetermined operation input for ending the game is performed by the player, the processor 81 determines to end the game. If the determination result in step S13 is negative, the process of step S1 is executed again. Thereafter, a series of processes of steps S1 to S13 are repeatedly executed until it is determined in step S13 to end the game. On the other hand, if the determination result in step S13 is affirmative, the processor 81 ends the game process shown in FIG. 36.

[0256] [4. Effects and Modifications of the Present Embodiment] According to the above embodiment, when an event occurs based on game processing, a density update range is generated, the density of each voxel corresponding to the density update range is decreased, and further, a material update range is generated, and the material of each voxel corresponding to the material update range is changed, thereby changing the appearance of the deformed voxel object. Also, by setting the material update range to a size that includes the density update range, the surface of the voxel object can be expressed in a new way. For example, when the voxel object is deformed such that a part of it appears to be destroyed, an appearance where a thin outer shell is peeled off around the destroyed part can be expressed.

[0257] In the above embodiment, the event was an event in which a player character or a fragment object performs a predetermined action on a voxel object (see FIGS. 30, 32, and 33), but the content of the event is arbitrary. For example, the event may be an event in which the voxel object reaches a predetermined state (for example, a parameter related to the voxel object reaches a predetermined value), or an event in which the game situation reaches a predetermined situation (for example, the game story progresses to a predetermined state).

[0258] In the above embodiment, the material after the change for the voxels within the material update range was an internal material based on the material before the change as shown in the first and second examples in the above [2-8. Change of Material], or a predetermined material as shown in the third example. Here, the material after the change may be determined according to various states in the game. For example, the game system 1 may determine the material after the change according to the type of event that triggers the material change process, the actions of the player character, the state of the player character at the time of the change process, the type and state of the voxel object on which the change process is performed, and so on.

[0259] In the above embodiment, the case where the display mesh and the determination mesh are generated has been described as an example. However, in other embodiments, one type of mesh that is used for both display and collision determination may be generated. That is, the display mesh may also be used for collision determination. Even when such one type of mesh is generated, by making changes using the above density update range and material update range, the same effects as those of the above embodiment can be achieved.

[0260] In the above embodiment, the update process of the density of the voxels based on the density update range and the update process of the material of the voxels based on the material update range corresponding to the density update range were executed at the same timing (see FIG. 37). In other embodiments, the above two update processes may be executed at different timings. For example, the above material update process may be executed in a frame after the frame in which the above density update process is executed, or the above density update process may be executed in a frame after the frame in which the above material update process is executed.

[0261] In the above embodiment, when processing is executed using data (in the sense including programs) in a certain information processing apparatus, a part of the data necessary for the processing may be transmitted from another information processing apparatus different from the certain information processing apparatus. At this time, the certain information processing apparatus may execute the above processing using the data received from another information processing apparatus and the data stored in itself.

[0262] In other embodiments, the information processing system may not include a part of the configuration in the above embodiment, or may not execute a part of the processing executed in the above embodiment. For example, in order for the information processing system to achieve a certain effect in the above embodiment, it may include a configuration for achieving the effect and execute the processing for achieving the effect, and may not include other configurations or execute other processing.

Industrial Applicability

[0263] The above-described embodiment can be used, for example, as a game system or a game program for the purpose of expressing, in a new method, the surface of an object after deformation when the object is deformed, for example.

Explanation of Signs

[0264] 1 Game system 2 Main body device 81 Processor 201 Player character 273, 293 Density update range 274 Material update range 294 First material update range 295 Second material update range

Claims

1. In a computer of an information processing apparatus, voxel data defined in a virtual space, for each of a plurality of voxels, density indicating the degree to which the space defined by the voxel is virtually occupied by the content, and material indicating the type of the content are at least set, and the voxel data is updated based on game processing, a display mesh corresponding to the voxel data and drawn based on a virtual camera is generated and updated by determining vertex coordinates of the display mesh based on at least the density included in the voxel data and determining the material of the display mesh based on at least the material included in the voxel data, drawing of the virtual space including the display mesh is performed based on the vertex coordinates of the display mesh and a texture corresponding to the material of the display mesh, When a first event occurs based on the game processing, a first voxel update range is generated in the virtual space, the density of each voxel corresponding to the first voxel update range in the virtual space among the voxel data is decreased, and further, an update is performed to change the material of each voxel corresponding to a second voxel update range having a size that encloses the first voxel update range, a game program.

2. In the computer, The game program according to claim 1, wherein the material of the voxel corresponding to the second voxel update range is changed to a destination material preset for each type of the material before the change.

3. The material of the voxel data is held as a material ID indicating the material, In the computer, Based on drawing setting information including at least texture information set for the material for each type of the material corresponding to the material ID and material data including at least a destination material ID indicating the destination material corresponding to the material, the material ID of the voxel corresponding to the second voxel update range is changed to a destination material ID corresponding to the material indicated by the material ID, the game program according to claim 2.

4. A plurality of the material IDs are held, In the computer, The game program according to claim 3, which causes the computer to change each of the material IDs of the voxels corresponding to the second voxel update range to the respective destination material IDs based on the material data.

5. The computer is caused to change the material of the voxels corresponding to the second voxel update range to a first material regardless of the material before the change, in the game program according to claim 1.

6. The game program according to any one of claims 1 to 5, wherein the second voxel update range has a shape obtained by expanding the first voxel update range.

7. The computer is caused to generate and update the vertices of the display mesh based on a method of setting vertices at coordinates based on the positions and the density of a plurality of surrounding voxels for a portion where a voxel having the density of a setting indicating existence and a voxel having the density of a setting indicating non-existence are adjacent to each other, based on the voxel data, and when the first event occurs, cause the update to reduce the density of each voxel corresponding to the first voxel update range to be equal to or less than the density of a setting indicating non-existence, in the game program according to any one of claims 1 to 5.

8. The computer is further caused to when a second event occurs based on the game process, generate a third voxel update range in the virtual space, and cause the update to change the material of each voxel corresponding to the third voxel update range in the virtual space to the destination material, in the game program according to any one of claims 2 to 4.

9. Voxel data defined in a virtual space, in which at least a density indicating the degree to which the space defined by each of a plurality of voxels is virtually occupied by the content and a material indicating the type of the content are set, is updated based on a game process, and a display mesh corresponding to the voxel data and drawn based on a virtual camera is generated and updated by determining vertex coordinates of the display mesh based on at least the density included in the voxel data and determining the material of the display mesh based on at least the material included in the voxel data. Based on the vertex coordinates of the display mesh and the texture corresponding to the material of the display mesh, draw the virtual space including the display mesh. When a first event occurs based on the game processing, generate a first voxel update range in the virtual space, reduce the density of each voxel corresponding to the first voxel update range in the virtual space among the voxel data, and further perform an update to change the material of each voxel corresponding to a second voxel update range having a size that encloses the first voxel update range. An information processing system.

10. The information processing system according to claim 9, wherein the material of the voxel corresponding to the second voxel update range is changed to a destination material preset for each type of the material before the change.

11. The material of the voxel data is held as a material ID indicating the material. Based on drawing setting information including at least texture information set for the material and material data including at least a destination material ID indicating the destination material corresponding to the material, for each type of the material corresponding to the material ID, the material ID of the voxel corresponding to the second voxel update range is changed to a destination material ID corresponding to the material indicated by the material ID. The information processing system according to claim 10.

12. A plurality of the material IDs are held. The information processing system according to claim 11, wherein based on the material data, each material ID of the voxel corresponding to the second voxel update range is changed to a respective destination material ID.

13. The information processing system according to claim 9, wherein the material of the voxel corresponding to the second voxel update range is changed to a first material regardless of the material before the change.

14. The information processing system according to any one of claims 9 to 13, wherein the second voxel update range has a shape obtained by expanding the first voxel update range.

15. Based on the voxel data, for a portion where a voxel having the density of the setting indicating existence and a voxel having the density of the setting indicating non-existence are adjacent, based on a method of setting vertices at coordinates based on the positions and the density of a plurality of surrounding voxels, generate and update the vertices of the display mesh. The information processing system according to any one of claims 9 to 13, wherein when the first event occurs, the update is performed to reduce the density of each voxel corresponding to the first voxel update range to be equal to or less than the density of the setting indicating non-existence.

16. The information processing system according to any one of claims 10 to 12, wherein when a second event occurs based on the game processing, a third voxel update range is generated in the virtual space, and an update is performed to change the material of each voxel corresponding to the third voxel update range in the virtual space among the voxel data to the destination material.

17. An information processing apparatus including a processor, The processor, updates voxel data defined in a virtual space, where at least a density indicating the degree to which the space defined by each of a plurality of voxels is virtually occupied by the content and a material indicating the type of the content are set, based on game processing. corresponding to the voxel data, generates and updates a display mesh drawn based on a virtual camera by determining vertex coordinates of the display mesh based on at least the density included in the voxel data and determining the material of the display mesh based on at least the material included in the voxel data. draws the virtual space including the display mesh based on the vertex coordinates of the display mesh and a texture corresponding to the material of the display mesh. An information processing apparatus that, when a first event occurs based on the game processing, generates a first voxel update range in the virtual space, reduces the density of each voxel corresponding to the first voxel update range in the virtual space among the voxel data, and further performs an update to change the material of each voxel corresponding to a second voxel update range having a size that encloses the first voxel update range.

18. An information processing system, voxel data defined in a virtual space, for each of a plurality of voxels, voxel data in which at least a density indicating the degree to which the space defined by the voxel is virtually occupied by its content and a material indicating the type of the content are set, is updated based on game processing, a display mesh corresponding to the voxel data and drawn based on a virtual camera is generated and updated by determining vertex coordinates of the display mesh based on at least the density included in the voxel data and determining a material of the display mesh based on at least the material included in the voxel data, drawing of the virtual space including the display mesh is performed based on vertex coordinates of the display mesh and a texture corresponding to the material of the display mesh, When a first event occurs based on the game processing, a first voxel update range is generated in the virtual space, the density of each voxel corresponding to the first voxel update range in the virtual space among the voxel data is decreased, and further, an update is performed to change the material of each voxel corresponding to a second voxel update range having a size that encloses the first voxel update range. A game processing method.

19. In the information processing system, The game processing method according to claim 18, wherein the material of the voxel corresponding to the second voxel update range is changed to a destination material preset for each type of the material before the change.

20. The material of the voxel data is held as a material ID indicating the material, In the information processing system, Based on drawing setting information including at least texture information set for the material for each type of the material corresponding to the material ID and material data including at least a destination material ID indicating the destination material corresponding to the material, the material ID of the voxel corresponding to the second voxel update range is changed to a destination material ID corresponding to the material indicated by the material ID. The game processing method according to claim 19.

21. A plurality of the material IDs are held, In the information processing system, The game processing method according to claim 20, wherein, based on the material data, each of the material IDs of the voxels corresponding to the second voxel update range is changed to a respective destination material ID.

22. In the information processing system, The game processing method according to claim 18, wherein the material of the voxels corresponding to the second voxel update range is changed to a first material regardless of the material before the change.

23. The game processing method according to any one of claims 18 to 22, wherein the second voxel update range has a shape obtained by expanding the first voxel update range.

24. In the information processing system, Based on the voxel data, for a portion where a voxel having the density of a setting indicating existence and a voxel having the density of a setting indicating non-existence are adjacent, based on a method of setting vertices at coordinates based on the positions and the density of a plurality of surrounding voxels, generate and update the vertices of the display mesh, The game processing method according to any one of claims 18 to 22, wherein when the first event occurs, the update is performed to reduce the density of each of the voxels corresponding to the first voxel update range to be equal to or less than the density of a setting indicating non-existence.

25. Further in the information processing system, The game processing method according to any one of claims 19 to 21, wherein when a second event occurs based on the game processing, a third voxel update range is generated in the virtual space, and an update is performed to change the material of each of the voxels corresponding to the third voxel update range in the virtual space to the destination material.

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