Program, image generating device, and image generating method

Abstract

To provide a technique that can improve an image quality of an object image by enabling generation of the object image using high quality image data without delay as needed.SOLUTION: A player terminal 1500 stores low image quality texture data 241 in an image generation memory 240 to generate an object image. For this purpose, it is determined whether a high image quality status condition is met. When it is determined that the high image quality status condition is met, high quality texture data 243 is generated from the low quality texture data 241 stored in the image generation memory 240 and is stored in the image generation memory 240, then the object image is generated by using the high image quality texture data 243. On the other hand, when the high image quality status condition is not met, the object image is generated by using the low image quality texture data 241.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to a program for generating an image of an object in a virtual three-dimensional space as seen from a virtual camera. [Background technology]

[0002] Conventionally, there has been known a game system in which a game space is formed by placing objects such as characters in a virtual three-dimensional space, and an image viewed from a virtual camera placed in this game space is generated as a game space image. To generate the game space image, a process is performed to map image data (texture data) representing the appearance of objects within the field of view of the virtual camera, thereby generating an object image for each object. In this case, if an object newly enters the field of view of the virtual camera, texture data relating to the appearance of the object is read from a storage unit or received from an external device connected via communication, transferred to and expanded in a memory for image generation, and used to generate the object image. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2001-167291 Summary of the Invention [Problem to be solved by the invention]

[0004] To achieve high-quality appearance representation of an object, it is necessary to use high-quality image data as its texture data. However, using high-quality image data for texture data results in a correspondingly large data size. Furthermore, since the capacity of image generation memory is limited, determining which data to store in image generation memory and whether to delete already stored data is one of the keys to high-speed image generation. That is, if the image data is not stored in image generation memory, the time it takes for the image data to be expanded in image generation memory and become available for use becomes an issue. In particular, the acquisition time required to acquire the image data from an external source can be a bottleneck. For example, in image generation requiring a high frame rate, delays in the generation of object images are unacceptable. Therefore, there has been a demand for a technology that enables the generation of object images using high-quality image data without delay as needed.

[0005] The problem that the present invention aims to solve is to provide a technology that can improve the image quality of object images by making it possible to generate object images using high-quality image data without delay as needed. [Means for solving the problem]

[0006] A first invention for solving the above problem is a program for causing a computer to generate an object image in a virtual three-dimensional space as seen from a virtual camera, the program comprising: storage control means (e.g., the player terminal calculation unit 210 and the low-quality texture storage control unit 231 in FIG. 5) for storing first image data for expressing the appearance of the object in an image generation memory (e.g., the image generation memory 240 in FIG. 5) provided in the computer; storage determination means (e.g., the storage determination unit 215 in FIG. 5) for determining whether second image data having a data size larger than that of the first image data for expressing the appearance of the object with higher image quality than that of the first image data is stored in the image generation memory; and storage determination means (e.g., the storage determination unit 215 in FIG. 5) for determining whether a high-quality image condition indicating that the object image should be generated using the second image data is satisfied. and object image generation control means (e.g., object image generation control unit 233 in FIG. 5) that (1) generates the object image using the second image data stored in the image generation memory when the memory determination means determines yes, (2) generates the object image using the first image data when both the memory determination means and the situation determination means determine no, and (3) generates the second image data based on the first image data and stores it in the image generation memory when the memory determination means determines no and the situation determination means determines yes, and then generates the object image using the second image data.

[0007] According to the first aspect of the present invention, first image data can be stored in an image generation memory and used to generate an object image. Specifically, the high-image-quality condition is determined to be satisfied when, for example, the image quality of an object image may affect its visibility. In this case, second image data with higher image quality than the first image data stored in the image generation memory can be generated and stored in the image generation memory, and then an object image can be generated using the second image data. On the other hand, if the high-image-quality condition is not satisfied, an object image can be generated using the first image data. This allows an object image to be generated using high-image-quality second image data only when the high-image-quality condition is satisfied. Furthermore, in this case, the second image data can be generated based on the first image data in the image generation memory and used to generate the object image. In other words, an object image can be generated without acquiring second image data from a storage unit or an external device during the game. Therefore, an object image can be generated using high-image-quality second image data without delay as needed, thereby improving the image quality of the object image.

[0008] In addition, as a second invention, the situation determination means may be configured to configure the program of the first invention so as to determine whether or not the high image quality situation conditions are satisfied by including in the high image quality situation conditions at least that the distance between the object and the virtual camera satisfies a predetermined close distance condition.

[0009] According to the second invention, when the virtual camera is close to the object, it is determined that the high image quality condition is satisfied, and second image data can be generated.

[0010] In addition, as a third invention, the situation determination means may configure the program of the second invention so as to determine whether or not the high image quality situation conditions are satisfied, by including in the high image quality situation conditions the satisfaction of a visibility improvement condition indicating that the field of view of the virtual camera has changed from a predetermined worsened field of view to a predetermined good field of view.

[0011] According to the third aspect of the present invention, when the field of view of the virtual camera changes from poor field of view to good field of view, it is determined that the image quality improvement condition is satisfied, and second image data can be generated.

[0012] Furthermore, as a fourth invention, the program of any of the first to third inventions may be configured to cause the computer to further function as a discard candidate setting means (e.g., the discard candidate setting unit 219 in FIG. 5) that sets the second image data as discard candidate data to be discarded from the image generation memory when a discard situation condition indicating that the second image data has reached a situation where it should be discarded from the image generation memory is met.

[0013] According to the fourth aspect of the present invention, of the second image data stored in the image generation memory, the second image data that satisfies the discard status condition can be set as discard candidate data.

[0014] In addition, as a fifth invention, the second image data discarding means may be configured as a program of the fourth invention, which determines whether or not the discard situation conditions are satisfied, with the discard situation conditions including at least that the distance between the object and the virtual camera satisfies a predetermined long distance condition.

[0015] According to the fifth invention, when the virtual camera is far from the object, it is determined that the discard situation condition is satisfied, and the second image data relating to the appearance of the object can be set as discard candidate data.

[0016] Furthermore, as a sixth invention, the program of any of the first to fifth inventions may be configured to cause the computer to further function as a discarding means (for example, the high-quality texture discarding unit 239 in Figure 5) that discards the second image data from the image generation memory when the free space in the image generation memory meets a predetermined small capacity condition.

[0017] According to the sixth aspect of the present invention, the second image data in the image generation memory can be discarded depending on the free space in the image generation memory.

[0018] Furthermore, as a seventh invention, the program of any of the first to sixth inventions may be configured to further cause the computer to function as a game progress control means (e.g., game progress control unit 211 in Figure 5) that communicates with a server system and controls the progress of a given online game in which the virtual three-dimensional space is the game space, and the memory control means acquires the first image data from the server system and stores it in the image generation memory.

[0019] According to the seventh invention, first image data relating to the appearance of an object to be placed in the game space is obtained from a server system and stored in an image generation memory, and can be used to generate an object image of the object in an online game and to generate second image data relating to its appearance.

[0020] An eighth aspect of the present invention is an image generating device that generates an object image of an object in a virtual three-dimensional space as seen from a virtual camera, the image generating device comprising: a storage control means for storing first image data for expressing the appearance of the object in an image generating memory provided in the image generating device; a storage determination means for determining whether second image data, which has a data size larger than that of the first image data and is for expressing the appearance of the object with higher image quality than that of the first image data, is stored in the image generating memory; and a situation determination means for determining whether a high image quality situation condition indicating that the object image should be generated using the second image data is satisfied. and an object image generation control means for (1) generating the object image using the second image data stored in the image generation memory when the memory determination means determines yes, (2) generating the object image using the first image data when both the memory determination means and the situation determination means determine no, and (3) generating the second image data based on the first image data, storing it in the image generation memory, and then generating the object image using the second image data when the memory determination means determines no and the situation determination means determines yes. (For example, player terminal 1500 in FIG. 1)

[0021] According to the eighth aspect of the invention, it is possible to realize an image generating device that has the same effects as the first aspect of the invention. [Brief explanation of the drawings]

[0022] [Figure 1] FIG. 1 is a diagram showing an example of the overall configuration of a game system. [Figure 2] FIG. 2 is a diagram showing an example of the device configuration of a player terminal. [Figure 3] FIG. 10 is a diagram showing an example of a game screen. [Figure 4] Schematic diagrams illustrating the principle of generating an object image. [Figure 5] FIG. 2 is a block diagram showing an example of the functional configuration of a player terminal. [Figure 6] FIG. 10 is a diagram showing an example of the data configuration of a field-of-view object table. [Figure 7] FIG. 2 is a block diagram showing an example of the functional configuration of a server system. [Figure 8] 10 is a flowchart illustrating the flow of a game process. [Figure 9] 10 is a flowchart illustrating the flow of an object image generation control process. DETAILED DESCRIPTION OF THE INVENTION

[0023] Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. Note that the present invention is not limited to the embodiments described below, and the forms to which the present invention can be applied are not limited to the following embodiments. In addition, in the description of the drawings, the same parts are given the same reference numerals.

[0024] [Overall configuration] Fig. 1 is a diagram showing an example of the overall configuration of a game system 1000 according to this embodiment. As shown in Fig. 1, the game system 1000 includes a server system 1100 and a player terminal 1500 as an image generating device owned by a user who is a player 2 of the game according to this embodiment, and these are connected via a communication line N so as to be able to communicate data with each other.

[0025] The communication line N refers to a communication path that allows data communication. In other words, the communication line N includes a dedicated line (dedicated cable) for direct connection, a LAN (Local Area Network) such as Ethernet (registered trademark), a telephone communication network, a cable network, the Internet, and other communication networks, and the communication method can be either wired or wireless.

[0026] The server system 1100 comprises a main unit 1101, a keyboard 1106, a touch panel 1108, and a storage 1140, and the main unit 1101 has a control board 1150 built in.

[0027] The control board 1150 is equipped with electronic components such as a CPU (Central Processing Unit) 1151, various microprocessors such as a GPU (Graphics Processing Unit) and a DSP (Digital Signal Processor), various IC memories 1152 such as a VRAM, RAM and ROM, and a communication device 1153. Note that part or all of the control board 1150 may be realized by an ASIC (Application Specific Integrated Circuit), an FPGA (Field-programmable gate array), or an SoC (System on a Chip).

[0028] The server system 1100 performs processing for operating the game of this embodiment by having the CPU 1151 and the like perform calculations based on predetermined programs and data. Specifically, the server system 1100 issues a unique account (player ID) to a player 2 who has completed user registration, and centrally manages information about the player 2 as user registration data 530 (see FIG. 7). The server system 1100 also handles processing related to the player 2's login / logout and distributes data necessary for running the game on the player terminal 1500. In other words, the game of this embodiment is realized as a kind of client-server online game. The player 2 accesses the server system 1100 from each player terminal 1500, logs in using the issued player ID, and enjoys the game of this embodiment.

[0029] 1, the server system 1100 may be configured to include multiple blade servers each assigned to one function, connected to each other via an internal bus for data communication. Alternatively, the server system 1100 may be configured to function as a whole as a server system 1100 by having multiple independent servers installed in remote locations communicate with each other via a communication line N.

[0030] The player terminal 1500 is a computer system that functions as a man-machine interface, and can connect to a communication line N via a mobile phone base station, a wireless communication base station, or the like, and perform data communication with the server system 1100. This player terminal 1500 can take the form of, for example, a smartphone, a mobile phone, a portable game device, a home game device, a controller for a home game device, an arcade game device, a personal computer, a tablet computer, a wearable computer, or the like.

[0031] Fig. 2 is a diagram showing an example of the device configuration of a smartphone, which is an example of a player terminal 1500. As shown in Fig. 2, the player terminal 1500 includes a directional input key 1502, a home key 1504, a touch panel 1506 that functions as an image display device and a contact position input device, an internal battery 1509, a speaker 1510, a microphone 1512, a control board 1550, and a memory card reader 1542 that can read and write data from and to a memory card 1540 that is a computer-readable storage medium. In addition, the player terminal 1500 is provided with a power button, a volume control button, etc., which are not shown.

[0032] The control board 1550 is equipped with various microprocessors such as a CPU 1551, a GPU, and a DSP; various IC memories 1552 such as a VRAM, a RAM, and a ROM; and a wireless communication module 1553 for wireless communication with a mobile phone base station or a wireless LAN base station connected to a communication line N. The control board 1550 is also equipped with so-called I / F circuits (interface circuits) 1557, such as a circuit for receiving signals from the direction input keys 1502 and the home key 1504, a driver circuit for the touch panel 1506, an output amplifier circuit for outputting audio signals to the speaker 1510, an audio signal generation circuit for generating an audio signal collected by the microphone 1512, and a signal input / output circuit for the memory card reader 1542. These elements equipped on the control board 1550 are electrically connected to each other via a bus circuit or the like, and are connected to enable reading and writing of data and sending and receiving of signals. Note that part or all of the control board 1550 may be configured using an ASIC, an FPGA, or an SoC.

[0033] The IC memory 1552 stores a game program and various setting data required to execute the game program. The game program and the like are downloaded from the server system 1100 at appropriate times. Alternatively, the game program and the like may be read from a separately obtained storage medium such as a memory card 1540. The CPU 1551 and the like execute the game program to perform calculations, and controls each section of the player terminal 1500 in response to operational inputs made to the touch panel 1506, directional input keys 1502, and home key 1504, thereby enabling Player 2 to play the game.

[0034] [Game Overview] 3 is a diagram showing an example of a game screen in this embodiment. In the game of this embodiment, background objects and the like are placed in a virtual three-dimensional space to form a game space, and character objects such as a player character 3 and a target enemy character 4 are placed within this space and their movements are controlled. The enemy character 4's appearance position and movements are defined in advance by script data, and it is AI-controlled, so that it automatically moves toward and attacks the player character 3.

[0035] The game screen is generated from the first-person viewpoint of the player character 3. Specifically, a virtual camera CM (see FIG. 4) is placed behind the player character 3 so that its shooting direction coincides with the line of sight of the player character 3, and is controlled to follow the player character 3. A game space image (so-called 3DCG) is generated by capturing an image of the game space with the virtual camera CM from the first-person viewpoint of the player character 3, and a game screen is displayed on the touch panel 1506, in which various information displays are superimposed on this image, such as a hit point gauge 12 indicating the number of remaining hit points of the player character 3, a bullet gauge 14 indicating the number of remaining bullets, and a sight 16. The gun 5 at the bottom center of the screen is the weapon held by the player character 3. The player 2 controls the player character 3 to move within the game space, and when he encounters an enemy character 4, he aims the sight 16 at it and fires.

[0036] [principle] 4 is a schematic diagram illustrating the principle of generating an object image in the player terminal 1500. In this embodiment, when generating an object image of an enemy character 4 (for example, 4a), texture data used to generate the object image is changed depending on the distance from the virtual camera CM (hereinafter referred to as the "camera distance").

[0037] 1. Generate object images In this embodiment, low-quality texture data is prepared in advance as first image data as texture data for expressing the appearance of an enemy character. When multiple types of texture data are used to generate an object image of one enemy character, low-quality texture data is prepared for each type. This low-quality texture data is downloaded from the server system 1100 to the player terminal 1500 along with the game program and the like prior to the start of the game, and stored in the storage unit 500 (see FIG. 5) (low-quality texture data stored in the character initial setting data in the game setting data 511 in the storage unit 500). Furthermore, the low-quality texture data of an enemy character that comes within the field of view of the virtual camera during the course of the game is read from the storage unit 500 and stored in the image generation memory 240 (see FIG. 5) (low-quality texture data 241 in the image generation memory 240).

[0038] During game play, the player terminal 1500 monitors whether a predetermined high-quality image condition is satisfied. The high-quality image condition is a condition indicating that a situation exists in which an object image should be generated using high-quality texture data as the second image data, and is, for example, "the inter-camera distance between the enemy character and the virtual camera satisfies a predetermined close-distance condition." The close-distance condition may be, for example, "the inter-camera distance is equal to or less than a predetermined distance Dt1." The high-quality texture data is texture data for expressing the appearance of the enemy character with higher quality than the low-quality texture data, and is texture data with a larger data size than the low-quality texture data.

[0039] Specifically, in this embodiment, enemy characters positioned within the field of view of the virtual camera are defined as in-field enemy characters, and a determination is made for each in-field enemy character as to whether or not the high image quality condition is satisfied (hereinafter referred to as "high image quality determination"). Then, for in-field enemy characters for which the high image quality determination is positive, object images are generated using high-quality texture data, and for in-field enemy characters for which the high image quality determination is negative, object images are generated using low-quality texture data.

[0040] For example, as shown in FIG. 4(a), an in-field-of-view enemy character 4a whose inter-camera distance D from the virtual camera CM is greater than a predetermined distance Dt1 is determined not to satisfy the high-image-quality condition. In this case, an object image of the in-field-of-view enemy character 4a is generated using low-image-quality texture data related to its appearance. The object image based on the low-image-quality texture data is then used to generate the game space image A11. This is because an in-field-of-view enemy character 4a that is far from the virtual camera CM occupies a small area in the game space image A11, and even if an object image is generated using low-image-quality texture data, the image quality does not significantly affect the appearance of the in-field enemy character 4a.

[0041] However, as the in-field enemy character 4a approaches the virtual camera CM, the area occupied by the in-field enemy character 4a in the game space image A13 also increases, as shown in FIG. 4(b). Therefore, if an object image is generated using low-quality texture data, the image quality will affect the appearance of the in-field enemy character 4a. The appearance of the in-field enemy character 4a will be perceived as a rough image (rough texture), which may hinder immersion in the game. Therefore, as shown in FIG. 4(b), for an in-field enemy character 4a whose inter-camera distance D from the virtual camera CM is equal to or less than a predetermined distance Dt1, the high-quality image condition is determined to be satisfied, and an object image of the in-field enemy character 4a is generated using high-quality texture data related to its appearance. The object image based on the high-quality texture data is then used to generate the game space image A13.

[0042] 2.Generating high-quality texture data The high-quality texture data is generated based on the low-quality texture data. In this embodiment, a known high-resolution process that converts a low-resolution image into a high-resolution image is performed as the high-quality image processing, and the high-quality texture data is generated from the low-quality texture data. For example, the high-quality image processing can be achieved by applying a high-resolution process using a super-resolution technology that utilizes a deep learning convolutional neural network.

[0043] Furthermore, when lossy compressed texture data is used as low-quality image data, noise removal processing using a machine learning model or the like may be included in the image quality improvement processing.

[0044] By doing so, it is possible to determine that the high-image-quality situation condition is satisfied for a field-of-view enemy character whose inter-camera distance from the virtual camera is equal to or less than the predetermined distance Dt1. In this case, high-image-quality texture data 243 is generated based on the low-image-quality texture data 241 stored in the image generation memory 240, and the high-image-quality texture data 243 is then stored in the image generation memory 240. An object image of the field-of-view enemy character can then be generated using the high-image-quality texture data 243. If high-image-quality texture data 243 has already been generated for the field-of-view enemy character and stored in the image generation memory 240, the object image can be generated using the high-image-quality texture data. Therefore, for a field-of-view enemy character that is close to the virtual camera and displayed large on the game screen, an object image can be generated using high-image-quality texture data. This allows for a high-image-quality appearance representation of the field-of-view enemy character, thereby improving its image quality. On the other hand, for a field-of-view enemy character that does not satisfy the high-image-quality situation condition, an object image can be generated using low-image-quality texture data. However, if high-quality texture data 243 is already stored in image generation memory 240, an object image for that in-field enemy character is generated using the high-quality texture data 243 even if the high-quality image situation conditions are not met. Also, by doing as described above, it is not necessary to acquire high-quality texture data from storage unit 500 or server system 1100 and expand it in image generation memory 240 in order to generate an object image using the high-quality texture data during the game. Therefore, object images can be generated using high-quality texture data without delay as needed, and the image quality of the object images can be improved.

[0045] It is also possible to consider a mode in which lossy compressed texture (e.g., JPEG image data) that cannot be directly used by the GPU (image generation unit 230 in FIG. 5) is obtained from the server system 1100 as low-quality texture data, noise is removed by noise removal processing, the data is then recompressed into a lossy compressed texture that can be directly used by the GPU, and the resulting data is stored in the image generation memory 240 and used to generate an object image. If the data size of the lossy compressed texture that cannot be directly used by the GPU is smaller than the lossy compressed texture that can be directly used by the GPU, the same effect as above can be achieved.

[0046] [Function Configuration] 1. Player terminal 5 is a block diagram showing an example of the functional configuration of a player terminal 1500 according to this embodiment. As shown in FIG. 5, the player terminal 1500 includes an operation input unit 100, a device processing unit 200, an image display unit 390, a sound output unit 392, a communication unit 394, and a terminal storage unit 500.

[0047] The operation input unit 100 is used by the player to input various operations, and can be realized by, for example, button switches, a joystick, a touchpad, a trackball, an acceleration sensor, an angular velocity sensor, a CCD module, etc. In Fig. 2, this corresponds to the direction input keys 1502, the home key 1504, and the touch panel 1506.

[0048] The device processing unit 200 can be realized by a processor, which is an arithmetic circuit such as a CPU, GPU, ASIC, or FPGA, or by electronic components such as an IC memory, and controls the input and output of data between the device and each unit including the operation input unit 100 and the terminal storage unit 500. The device processing unit 200 performs various types of arithmetic processing based on predetermined programs and data, operation input signals from the operation input unit 100, data received from the server system 1100, etc., and centrally controls the operation of the player terminal 1500. In Fig. 2, this corresponds to the control board 1550 and its CPU 1551.

[0049] The terminal processing unit 200 includes a player terminal calculation unit 210 , an image generation unit 230 , a sound generation unit 292 , and a communication control unit 294 .

[0050] Prior to the start of the game, the player terminal calculation unit 210 downloads and acquires the game program 501 and game setting data 511 from the server system 1100, and executes various calculation processes to make the player terminal 1500 function as a terminal for the player to play the game. For example, the player terminal calculation unit 210 includes a game progress control unit 211, a field-of-view object management unit 213, a memory determination unit 215, an image quality improvement status determination unit 217, and a discard candidate setting unit 219.

[0051] The game progression control unit 211 controls the progress of the game using the game setting data 511. Specifically, it executes (1) processing for arranging background objects and the like to form a game space, (2) processing for arranging a player character in the game space and controlling the player character's actions in response to operation input to the operation input unit 100, (3) processing for arranging a virtual camera behind the player character and controlling it to follow, (4) processing for arranging an enemy character in the game space and automatically controlling its actions, (5) processing related to attack hit determination and damage determination and reflection thereof, and (6) processing for determining whether the game end conditions have been met.

[0052] The in-field object management unit 213 manages enemy characters located within the field of view of the virtual camera as in-field enemy characters. Specifically, if there is a new enemy character that comes within the field of view of the virtual camera, it adds it to the in-field object table 513 as an in-field enemy character, and also calculates the inter-camera distance between the virtual camera and each in-field enemy character as needed, and sets it in the in-field object table 513 for management.

[0053] The memory determination unit 215 determines, for each in-field enemy character, whether or not high-quality texture data 243 relating to the appearance of that in-field enemy character is stored in the image generation memory 240 (hereinafter referred to as "memory determination"). In this embodiment, when a high-quality texture data generation unit 235 (described later) in the image generation unit 230 generates high-quality texture data 243 and stores it in the image generation memory 240, the storage area (storage destination address) is registered in the storage destination list 515. The memory determination unit 215 performs memory determination depending on whether or not a storage area is registered in this storage destination list 515. In other words, if the storage area of the in-field enemy character to be determined is registered in the storage destination list 515, the memory determination is positive, and if not registered, the memory determination is negative.

[0054] The high image quality situation determination unit 217 determines whether or not the high image quality situation condition is satisfied for each enemy character within the field of view (high image quality determination). In this embodiment, it is determined that the high image quality situation condition is satisfied for an enemy character within the field of view whose inter-camera distance from the virtual camera satisfies the short distance condition described above.

[0055] The discard candidate setting unit 219 determines (discard status determination) whether or not each piece of high-quality texture data 243 stored in the image generation memory 240 satisfies a discard status condition indicating that the data should be discarded from the image generation memory 240. The high-quality texture data 243 that satisfies the discard status condition is then set as discard candidate data.

[0056] In this embodiment, the discard status condition is that "the inter-camera distance between the in-field enemy character and the virtual camera satisfies a predetermined long distance condition." The long distance condition can be, for example, "the inter-camera distance is equal to or greater than a predetermined distance Dt2." The discard candidate setting unit 219 then monitors whether the discard status condition is satisfied for each in-field enemy character, and if there is an in-field enemy character whose inter-camera distance is equal to or greater than the predetermined distance Dt2, the discard candidate setting unit 219 registers the high-quality texture data 243 relating to the appearance of that character as discard candidate data in the discard candidate list 517. It is preferable that the distance Dt2 be greater than the distance Dt1, which is the distance threshold for the short distance condition.

[0057] The image generation unit 230 generates a game space image (e.g., 3DCG) of the virtual three-dimensional space seen from the virtual camera based on the processing result of the player terminal calculation unit 210. Then, based on the generated game space image, it generates an image signal for displaying one game screen per frame time (e.g., 1 / 60 seconds) and outputs the generated image signal to the image display unit 390. For example, the image generation unit 230 is realized by a processor such as a GPU or a digital signal processor (DSP), a video signal IC, a program such as a video codec, an IC memory for drawing frames such as a frame buffer, an IC memory used for expanding texture data, and the like. In this embodiment, the image generation unit 230 includes a low-quality texture storage control unit 231, an object image generation control unit 233, a high-quality texture discarding unit 239, and an image generation memory 240.

[0058] The low-quality texture storage control unit 231 reads out low-quality texture data relating to the appearance of an enemy character that has been newly designated as an enemy character within the field of view of the virtual camera by the field-of-view object management unit 213 from the storage unit 500 (character initial setting data of the game setting data 511), and controls storage in the image generation memory 240. At this time, the storage area in the image generation memory 240 for the low-quality texture data 241 is registered in the storage destination list 515.

[0059] The object image generation control unit 233 sequentially processes enemy characters within the field of view (hereinafter referred to as "target enemy characters within the field of view"), and controls the generation of the object images based on the results of memory determination and / or high image quality determination for the target enemy characters within the field of view.

[0060] Specifically, (1) if the memory determination for the enemy character within the target field of view is positive, control is performed to generate an object image of the enemy character within the target field of view using high-quality texture data 243 related to its appearance. Also, (2) if the memory determination and high-quality image determination for the enemy character within the target field of view are both negative, control is performed to generate an object image of the enemy character within the target field of view using low-quality texture data 241 related to its appearance. Also, (3) if the memory determination for the enemy character within the target field of view is negative and the high-quality image determination is positive, control is performed to generate high-quality texture data from the low-quality texture data 241 related to its appearance, store it in image generation memory 240, and use it to generate an object image of the enemy character within the target field of view.

[0061] The object image generation control unit 233 includes a high-quality texture data generation unit 235 and an object image generation unit 237 .

[0062] The high-quality texture data generation unit 235 generates high-quality texture data by performing high-quality processing on the low-quality texture data 241 under the control of the object image generation control unit 233. The high-quality texture data generation unit 235 then stores the generated high-quality texture data 243 in the image generation memory 240, and registers the storage area in the image generation memory 240 in the storage destination list 515.

[0063] Under the control of the object image generation control unit 233, the object image generation unit 237 generates an object image using low-quality texture data 241 or high-quality texture data 243 relating to the appearance of the enemy character within the target field of view.

[0064] The high-quality texture discard unit 239 performs free space monitoring processing to discard high-quality texture data 243 in the image generation memory 240. Specifically, in the free space monitoring processing, the unit repeatedly determines whether the free space in the image generation memory 240 satisfies a small space condition (discard determination), and monitors whether the small space condition is met. The small space condition may be, for example, "free space is equal to or less than a predetermined space Ct." If the small space condition is met, the high-quality texture data 243 is discarded from the image generation memory 240. In this embodiment, the high-quality texture data 243 that has been set as discard candidate data by the discard candidate setting unit 219 and set in the discard candidate list 517 is discarded from the image generation memory 240.

[0065] The sound generation unit 292 is realized, for example, by a digital signal processor (DSP), a processor such as a voice synthesis IC, or an audio codec for playing audio files, and generates audio signals for game sound effects, background music, and various operation sounds, and outputs them to the sound output unit 392.

[0066] The communication control unit 294 performs communication connection and data processing for data communication with an external device (for example, the server system 1100) via the communication unit 394, thereby realizing data exchange with the external device.

[0067] The image display unit 390 displays various screens, such as a game screen, based on the image signal input from the image generation unit 230. For example, this can be realized by an image display device such as a flat panel display, a projector, or a head-mounted display. In FIG. 2, this corresponds to the touch panel 1506.

[0068] The sound output unit 392 emits sound effects, background music, etc. related to the game based on the audio signal input from the sound generation unit 292. In FIG.

[0069] The communication unit 394 realizes communication by connecting to the communication line N. For example, it can be realized by a wireless communication device, a modem, a TA, a jack of a wired communication cable, a control circuit, etc. In FIG. 2, the wireless communication module 1553 corresponds to this.

[0070] The terminal storage unit 500 stores in advance or temporarily stores each time processing is performed programs for operating the player terminal 1500 and implementing the functions of the player terminal 1500, as well as data used during execution of these programs. For example, this can be realized by IC memory such as RAM or ROM, a magnetic disk such as a hard disk, or an optical disk such as a CD-ROM or DVD. In FIG. 2, this corresponds to the IC memory 1552 and the memory card 1540.

[0071] The terminal storage unit 500 also stores a game program 501, game setting data 511, a field-of-view object table 513, a storage destination list 515, a discard candidate list 517, and play data 519. In addition, information such as timers, counters, and various flags, as well as other data necessary for the progress of the game, such as game sounds, are also stored as appropriate.

[0072] The game program 501 is application software that is read and executed by the device processing unit 200 to realize the functions of the player terminal calculation unit 210, image generation unit 230, sound generation unit 292, and communication control unit 294. Alternatively, the game program 501 may be a dedicated program corresponding to the technical method for realizing an online game, or may be configured by a web browser program and a plug-in for realizing interactive image display, etc. In this embodiment, the game program 501 is downloaded from the server system 1100 together with game setting data 511, etc., and stored in the storage unit 500.

[0073] The game setting data 511 includes game space initial setting data and character initial setting data, as shown in its original game setting data 560 in Fig. 7. The character initial setting data related to enemy characters includes low-quality texture data related to their appearances.

[0074] The field-of-view object table 513 stores a list of enemy characters (field-of-view enemy characters) positioned within the field of view of the virtual camera. Specifically, as shown in Fig. 6, the field-of-view object table 513 stores the object ID of the field-of-view enemy character and its distance from the virtual camera (inter-camera distance).

[0075] The storage destination list 515 stores the storage areas (storage destination addresses) of the low-quality texture data 241 and the high-quality texture data 243 stored in the image generation memory 240.

[0076] The discard candidate list 517 stores a list of high-quality texture data 243 that has been designated as discard candidate data by the discard candidate setting unit 219 .

[0077] The play data 519 stores various data describing the progress of the game, such as the player ID (account), the current player level, a list of characters that can be used as player characters and their current ability values, and the status of the player character and enemy characters in the game being played.

[0078] 2. Server System Fig. 7 is a block diagram showing an example of the functional configuration of the server system 1100. As shown in Fig. 7, the server system 1100 of this embodiment includes an operation input unit 100s, a server processing unit 200s, an image display unit 390s, a sound output unit 392s, a communication unit 394s, and a server storage unit 500s.

[0079] The operation input unit 100s is used to input various operations for system management, maintenance, etc., and can be realized by, for example, a keyboard, a mouse, a touch panel, etc. In FIG. 1, this corresponds to the keyboard 1106 and the touch panel 1108.

[0080] The server processing unit 200s can be realized by electronic components such as a processor, which is an arithmetic circuit such as a CPU, GPU, ASIC, or FPGA, or an IC memory, and controls the input and output of data between the operation input unit 100s and each unit of the device, including the server storage unit 500s. The server processing unit 200s performs various arithmetic processing based on predetermined programs and data, operation input signals from the operation input unit 100s, data received from the player terminals 1500, etc., and controls the operation of the server system 1100. In FIG. 1, this corresponds to the control board 1150 and its CPU 1151.

[0081] The server processing unit 200s includes an account management unit 270, a game management unit 280, an image generation unit 290s, a sound generation unit 292s, and a communication control unit 294s.

[0082] The account management unit 270 performs processes related to user registration and manages the data of each registered user (player) linked to the account. For example, it can execute processes such as issuing an account to a user who has completed the registration procedure and generating user registration data 530, registering and managing personal information for each account, and managing login and logout processes and their history.

[0083] The game management unit 280 performs various processes related to the management of game execution in the player terminal 1500. For example, it can perform processes such as transmitting distribution data 550 to the player terminal 1500 in response to a request from the player terminal 1500, and acquiring data necessary for managing game play from the player terminal 1500 to update the user registration data 530.

[0084] The image generating unit 290s generates images relating to system management of the server system 1100 and outputs them to the image display unit 390s.

[0085] The sound generation unit 292s is realized by executing an IC or software that generates or decodes audio data, and generates or decodes audio data such as operation sounds and background music related to system management and video distribution of the server system 1100. Audio signals related to system management are output to the sound output unit 392s.

[0086] The communication control unit 294s performs communication connection and data processing for data communication with an external device (for example, the player terminal 1500) via the communication unit 394s, and realizes data exchange with the external device.

[0087] The image display unit 390s displays various screens for system management and the like based on the image signals input from the image generation unit 290s. For example, this can be realized by an image display device such as a flat panel display, a projector, or a head-mounted display. In FIG. 1, this corresponds to the touch panel 1108.

[0088] The sound output unit 392s outputs the audio signal input from the sound generation unit 292s. In Fig. 1, this corresponds to a speaker (not shown) provided in the main device 1101 or the touch panel 1108.

[0089] The communication unit 394s realizes communication by connecting to the communication line N. For example, it can be realized by a wireless communication device, a modem, a TA (terminal adapter), a jack for a wired communication cable, a control circuit, etc. In FIG. 1, this corresponds to the communication device 1153.

[0090] The server storage unit 500s stores in advance or temporarily stores each time processing is performed programs for operating the server system 1100 and realizing various functions of the server system 1100, data used during execution of these programs, etc. For example, this can be realized by IC memory such as RAM or ROM, a magnetic disk such as a hard disk, or an optical disk such as a CD-ROM or DVD. In FIG. 1, this corresponds to the IC memory 1152 and storage 1140.

[0091] The server storage unit 500s also stores an account management program 503, a game management program 505, user registration data 530, and distribution data 550. In addition, other information such as timers, counters, and various flags is also stored as appropriate.

[0092] The account management program 503 is a program that is read and executed by the server processing unit 200s to realize the functions of the account management unit 270. The game management program 505 is a program that is read and executed by the server processing unit 200s to realize the functions of the game management unit 280.

[0093] The user registration data 530 is prepared for each player registered by the account management unit 270, and stores various data for management related to the game play of the player, including the player ID (account).

[0094] The distribution data 550 includes a game program 551 and game setting data 560. These are the originals of the game program 501 and game setting data 511 distributed to the player terminal 1500.

[0095] The game setting data 560 stores various initial setting data for executing the game of this embodiment. The game setting data 560 includes game space initial setting data 561 and character initial setting data 563.

[0096] The game space initial setting data 561 is initial setting data for forming the game space, and for example, for each background object, its model data, texture data, placement position data, etc. are stored.

[0097] The character initial setting data 563 is initial setting data that defines character objects such as the player character and enemy characters. This character initial setting data 563 is prepared for each character object. It stores model data, texture data, motion data, and initial values of various ability parameters such as attack power, defense power, and HP, in association with the object ID. In this embodiment, the character initial setting data 563 for at least the enemy characters includes one or more low-quality texture data 565 related to their appearance.

[0098] [Processing flow] 8 is a flowchart illustrating the flow of game processing in the player terminal 1500. The processing described here is realized by the terminal processing unit 200 reading and executing the game program 501.

[0099] In the game processing, first, the game progress control unit 211 starts controlling the progress of the game (step S1). Specifically, the game progress control unit 211 arranges background objects to form a game space, and arranges a player character and an enemy character within it. Then, it starts automatic control of the enemy character and moves the player character in response to the player's operation input. It also arranges a virtual camera behind the player character and starts tracking control of it. It also starts other controls that are basically required for controlling the progress of the game as appropriate.

[0100] The high-quality texture discarding unit 239 also starts free space monitoring processing (step S3). This processing monitors the free space in the image generation memory 240, and when the free space falls below a predetermined capacity Ct, the high-quality texture data 243 that has been designated as discard candidate data and registered in the discard candidate list 517 is discarded from the image generation memory 240.

[0101] Once game progress control and necessary processing have begun, the field-of-view object management unit 213 then monitors whether or not any enemy characters have newly entered the field of view of the virtual camera. If an enemy character has entered the field of view (step S5: YES), the enemy character is added (set) as an in-field enemy character in the field-of-view object table 513, and management of the inter-camera distance begins (step S7). That is, the field-of-view object management unit 213 continually calculates the inter-camera distance between the virtual camera and the in-field enemy character, and updates the field-of-view object table 513.

[0102] Then, upon addition of the in-field enemy character in step S7, the low-quality texture storage control unit 231 in the image generation unit 230 reads out the low-quality texture data 241 of the new in-field enemy character from the storage unit 500 and stores it in the image generation memory 240 (step S9).

[0103] Further, the discard candidate setting unit 219 performs a discard situation determination for each of the enemy characters within the field of view based on the inter-camera distance to determine whether or not the discard situation condition is satisfied (step S11). If there is an enemy character within the field of view for which the discard situation determination is affirmative (step S13: YES), the high-quality texture data 243 relating to its appearance is set as discard candidate data and registered in the discard candidate list 517 (step S15).

[0104] Next, the memory determination unit 215 refers to the storage destination list 515 and performs a memory determination as to whether or not high-quality texture data 243 relating to the appearance of each enemy character within the field of view is stored in the image generation memory 240 (step S17).

[0105] Furthermore, the image quality improvement status determination unit 217 performs an image quality improvement determination for each enemy character within the field of view based on the inter-camera distance to determine whether or not the image quality improvement status condition is satisfied (step S19).

[0106] Thereafter, the object image generation control unit 233 in the image generation unit 230 performs an object image generation control process (step S20). Fig. 9 is a flowchart for explaining the flow of the object image generation control process.

[0107] As shown in FIG. 9, in the object image generation control process, the in-field enemy characters are sequentially set as target in-field enemy characters, and the process of loop A is executed for each in-field enemy character (steps S201 to S215).

[0108] Then, in loop A, first, the process branches depending on the result of memory determination for the enemy character within the target field of view. That is, if the memory determination is affirmative (step S203: YES), the process proceeds to step S211.

[0109] On the other hand, if the memory determination is negative (step S203: NO), the process branches depending on the result of the image quality improvement determination for the enemy character within the target field of view. If the image quality improvement determination is positive (step S205: YES), the process proceeds to step S207. That is, if the memory determination is negative and the image quality improvement determination is positive, the process proceeds to step S207. Then, in step S207, the high-quality texture data generation unit 235 performs image quality improvement processing by applying a known high-resolution process, and generates high-quality texture data from the low-quality texture data 241 related to the appearance of the enemy character within the target field of view. Thereafter, the generated high-quality texture data 243 is stored in the image generation memory 240, and the storage area is registered in the storage destination list 515 (step S209), after which the process proceeds to step S211.

[0110] If the image quality improvement determination is negative (step S205: NO), that is, if the results of both the storage determination and the image quality improvement determination are negative, the process proceeds to step S213.

[0111] Then, in step S211, the object image generation unit 237 generates an object image of the enemy character within the target field of view, using high-quality texture data 243 related to the appearance of the enemy character within the target field of view, which is stored in the image generation memory 240. Also, in step S213, the object image generation unit 237 generates an object image of the enemy character within the target field of view, using low-quality texture data 241 related to the appearance of the enemy character within the target field of view, which is stored in the image generation memory 240.

[0112] Then, when the processing of loop A has been performed for all enemy characters within the field of view, the object image generation control processing is terminated. Then, as shown in Fig. 8, the image generation unit 230 generates a game space image using the object images of the enemy characters within the field of view as the object images generated in the previous object image generation control processing (step S31), and causes the image display unit 390 to display the game screen (step S33).

[0113] Thereafter, it is determined whether the game is to be ended, and if the game is not to be ended (step S35: NO), the process returns to step S5 and the above-mentioned processing is repeated.

[0114] As described above, according to this embodiment, an object image can be generated using high-quality image data without delay as needed, thereby improving the quality of the object image.

[0115] The forms to which the present invention can be applied are not limited to the above-described embodiments, and constituent elements can be added, omitted, or modified as appropriate.

[0116] For example, in the above embodiment, an example was shown in which the principle of generating object images was applied to generating object images of enemy characters, but the principle can also be applied to generating object images of various objects in the game space, such as objects other than enemy characters, for example, player characters, various items such as equipment for player characters and enemy characters, background objects, etc. Furthermore, the games to which the principle of generating object images is applicable are not limited to games that generate a first-person perspective game screen as exemplified.

[0117] Furthermore, the high-image-quality situation condition can be set as appropriate, in addition to the "camera distance satisfying the close distance condition" exemplified in the above embodiment. For example, a high-image-quality situation condition may be set such that "a visibility improvement condition indicating that the virtual camera's field of view has changed from a predetermined poor field of view to a predetermined good field of view is satisfied." In this case, when the player character's surrounding environment changes and the visibility improvement condition is satisfied, object images of enemy characters within the field of view and other objects within the field of view of the virtual camera are generated using high-image-quality texture data. Specifically, when the player character moves from a dark place to a bright place, or when the weather setting around the player character changes from rainy to sunny, or when the fog clears, the visibility improvement condition is deemed to be satisfied, and a positive image quality determination is made.

[0118] Alternatively, the high image quality determination may be performed using the high image quality situation condition "being a locked-on enemy character." In this case, an object image is generated using high-image quality texture data for the locked-on enemy character. Furthermore, when a multiplayer game in which multiple players participate is played as an online game, the high image quality determination may be performed using the high image quality situation condition "being a player character controlled by a player who is registered as a friend." In this case, an object image is generated using high-image quality texture data for the player character of the player who is registered as a friend.

[0119] Furthermore, the high image quality determination may be performed by combining the multiple high image quality condition conditions exemplified above. For example, the high image quality determination may be performed by including both the satisfaction of the close distance condition and the satisfaction of the visibility improvement condition in the high image quality condition. The high image quality determination may be made positive if either one of the conditions is satisfied, or may be made positive if both conditions are satisfied.

[0120] The magnification of the high-resolution processing may also be made so that the player can specify it. For example, the player may specify it by inputting a value within the range of settable magnifications, or the magnification may be specified in stages, for example, by selecting from three levels: "large," "medium," and "small." [Explanation of symbols]

[0121] 1000...Game System 1500...Player terminal 100...Operation input section 200...Terminal processing section 210...Player terminal calculation unit 211...Game progress control unit 213...Object Management Unit 215...Memory judgment section 217...High-definition image status determination unit 219...Candidate for deletion setting unit 230...Image generation unit 231...Low quality texture memory control unit 233...Object image generation control unit 235...High-quality texture data generation unit 237...Object image generation unit 239…High-quality texture discarding section 240...Image generation memory 241...Low quality texture data 243...High-resolution texture data 292...Sound generation section 294...Communication control unit 390...Image display unit 392...Sound output unit 394…Communications Department 500...Device memory section 501...Game Program 511...Game setting data 513...Field of view object table 515...Memory destination list 517...Candidate list for deletion 519...Play data 1100...Server system 100s...Operation input section 200s...Server processing section 270...Account Management Department 280...Game Management Department 290s...Image generation section 292s…sound generation section 294s…Communication control unit 390s...Image display section 392s...Sound output section 394s…Communication Department 500s...Server storage section 503...Account management program 505...Game Management Program 530...User registration data 550...Distribution data 560...Game setting data 561...Game space initial setting data 563...Character initial setting data 565...Low quality texture data N...Communication line 2...Player

Claims

1. A program for causing a computer to generate an object image of an object in a virtual three-dimensional space viewed from a virtual camera, the program comprising: a storage control means for storing first image data for expressing the appearance of the object in an image generation memory provided in the computer; a situation determination means for determining whether or not a high image quality situation condition is satisfied, which indicates that the object image should be generated using second image data having a data size larger than that of the first image data in order to express the appearance of the object with higher image quality than that of the first image data; an object image generation control means for, when the second image data is not stored in the image generation memory, 1) generating the object image using the first image data when the situation determination means determines "No," and 2) generating the second image data based on the first image data and then generating the object image using the second image data when the situation determination means determines "Yes." causing the computer to function as the situation determination means determines whether the high image quality situation conditions are satisfied, including a condition that a visibility improvement condition indicating that the visibility of the virtual camera has changed from a predetermined worse visibility to a predetermined good visibility being satisfied as the high image quality situation conditions. program.

2. A program for causing a computer to generate an object image of an object in a virtual three-dimensional space viewed from a virtual camera, the program comprising: a storage control means for storing first image data for expressing the appearance of the object in an image generation memory provided in the computer; a storage determination means for determining whether second image data having a data size larger than that of the first image data, for expressing the appearance of the object with higher image quality than that of the first image data, is stored in the image generation memory; (1) when the storage determination means determines that the object image is generated using the second image data stored in the image generation memory, (2) when the storage determination means determines that the object image is generated using the second image data and the image quality is not high, which indicates that the object image should be generated using the second image data, the object image is generated using the first image data, and (3) when the storage determination means determines that the object image is generated using the first image data and the image quality is high, the object image is generated using the second image data. A program for causing the computer to function as a

3. a discard candidate setting means for setting the second image data as discard candidate data to be discarded from the image generation memory when a discard situation condition indicating that the second image data should be discarded from the image generation memory is satisfied; 3. The program according to claim 2, for causing the computer to further function as:

4. the discard candidate setting means determines whether the discard situation conditions are satisfied, including at least a condition that the distance between the object and the virtual camera satisfies a predetermined long distance condition. The program according to claim 3.

5. a discarding means for discarding the second image data from the image generation memory when the free space in the image generation memory satisfies a predetermined small space condition; 5. The program according to claim 2, for causing the computer to further function as:

6. a game progress control means for communicating with a server system and controlling the progress of a given online game in which the virtual three-dimensional space is used as a game space; and further causing the computer to function as the storage control means acquires the first image data from the server system and stores it in the image generation memory; The program according to any one of claims 2 to 5.

7. An image generation device that generates an object image of an object in a virtual three-dimensional space viewed from a virtual camera, a storage control means for storing first image data for expressing the appearance of the object in an image generation memory included in the image generation device; a situation determination means for determining whether or not a high image quality situation condition is satisfied, which indicates that the object image should be generated using second image data having a data size larger than that of the first image data in order to express the appearance of the object with higher image quality than that of the first image data; an object image generation control means for, when the second image data is not stored in the image generation memory, 1) generating the object image using the first image data when the situation determination means determines "no," and 2) generating the second image data based on the first image data and then generating the object image using the second image data when the situation determination means determines "yes." Equipped with the situation determination means determines whether the high image quality situation conditions are satisfied, including a condition that a visibility improvement condition indicating that the visibility of the virtual camera has changed from a predetermined worse visibility to a predetermined good visibility being satisfied as the high image quality situation conditions. Image generating device.

8. An image generation device that generates an object image of an object in a virtual three-dimensional space viewed from a virtual camera, a storage control means for storing first image data for expressing the appearance of the object in an image generation memory included in the image generation device; a storage determination means for determining whether second image data having a data size larger than that of the first image data, for expressing the appearance of the object with higher image quality than that of the first image data, is stored in the image generation memory; (1) when the storage determination means determines that the object image is generated using the second image data stored in the image generation memory, (2) when the storage determination means determines that the object image is generated using the second image data and the image quality is not high, which indicates that the object image should be generated using the second image data, the object image is generated using the first image data, and (3) when the storage determination means determines that the object image is generated using the first image data and the image quality is high, the object image is generated using the second image data and the second image data is stored in the image generation memory, and the object image is generated using the second image data. An image generating device comprising:

9. 1. An image generation method for a computer to generate an object image of an object in a virtual three-dimensional space viewed from a virtual camera, comprising: storing first image data for expressing the appearance of the object in an image generating memory included in the computer; performing a situation determination to determine whether or not a high image quality situation condition is satisfied, which indicates that the object image should be generated using second image data that is larger in data size than the first image data and that expresses the appearance of the object with higher image quality than the first image data; When the second image data is not stored in the image generation memory, 1) when the situation determination is negative, the object image is generated using the first image data, and 2) when the situation determination is positive, the second image data is generated based on the first image data, and then the object image is generated using the second image data, performing object image generation control. Including, The determination of the situation includes determining whether or not the high image quality situation condition is satisfied, the high image quality situation condition including a condition that a visibility improvement condition indicating that the visibility of the virtual camera has changed from a predetermined worse visibility to a predetermined good visibility being satisfied as the high image quality situation condition. Image generation method.

10. 1. An image generation method for a computer to generate an object image of an object in a virtual three-dimensional space viewed from a virtual camera, comprising: storing first image data for expressing the appearance of the object in an image generating memory included in the computer; performing a storage determination to determine whether second image data having a data size larger than that of the first image data, for expressing the appearance of the object with higher image quality than that of the first image data, is stored in the image generation memory; (1) When the memory determination is determined to be positive, the object image is generated using the second image data stored in the image generation memory; (2) When the memory determination is determined to be negative and the image quality is not high, which indicates that the object image should be generated using the second image data, the object image is generated using the first image data; and (3) When the memory determination is determined to be negative and the image quality is high, the object image is generated based on the first image data, stored in the image generation memory, and then the object image is generated using the second image data, performing object image generation control. An image generation method comprising:

Images