Method, apparatus, electronic device and storage medium for generating a level of detail model

Abstract

The present disclosure provides a method, apparatus, electronic device, and storage medium for generating a level of detail model. The method includes: performing a mesh simplification process on a target model to obtain a top-layer mesh model; determining a residual layer mesh model using a mesh refinement algorithm based on the top-layer mesh model and set model parameters, and recording the refinement parent-child relationship between the top-layer mesh model and the lower-layer mesh model; texture mapping the bottom-layer mesh model to obtain a bottom-layer texture model; and determining a level of detail model based on the mesh refinement parent-child relationship and the bottom-layer texture model. The level of detail model constructed in the present disclosure has a texture map with consistent geometric precision and hierarchically sharpened texture details, and the consistent geometric precision can avoid "crack" defects.

Description

[Technical Field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims priority to Chinese Patent Application No. 202211700543.5 filed on December 29, 2022, the entire contents of which are incorporated herein by reference.

[0002] The present disclosure relates to the field of data processing technology, and in particular to a method, apparatus, electronic device and storage medium for generating a level of detail model. [Background technology]

[0003] Level of Detail (LOD) technology is a technology for accelerating model rendering. During rendering, resource allocation for object rendering is determined based on the distance between the camera and the object, thereby reducing the number of polygons and the level of detail of unimportant objects. Therefore, generating an LOD model usually requires simplifying the model to different degrees, and during simplification, the effect of simplifying both geometric details and texture details can be achieved.

[0004] In related art, LOD models are typically generated using a policy that simplifies geometric details and compresses textures, resulting in "cracks" at adjacent locations of patches between different levels due to inconsistencies in the accuracy of the geometric models. In indoor scenes, due to the presence of many planar structures, the model itself may be represented with very few polygons. During rendering, the geometric primitives themselves are very scarce, and the texture map primarily occupies memory space and rendering time. Therefore, texture map LOD alone can achieve good results and avoid "cracks" caused by inconsistencies in the accuracy of the geometric models. The present disclosure provides an LOD model generation scheme that takes into account the planar characteristics of indoor scenes and primarily relies on texture map LOD. Summary of the Invention [Means for solving the problem]

[0005] The technical problem that the embodiments of the present disclosure aim to solve is to provide a method, an apparatus, an electronic device, and a storage medium for generating a level of detail model.

[0006] According to one aspect of an embodiment of the present disclosure, there is provided a method for generating a level of detail model, the method comprising: performing a mesh simplification process on the target model to obtain a top layer mesh model; determining a residual layer mesh model using a mesh refinement algorithm based on the top layer mesh model and the set model parameters, and recording a refinement parent-child relationship between the upper layer mesh model and the lower layer mesh model; a step of texture mapping the lowest layer mesh model to obtain a lowest layer texture model, the lowest layer mesh model being the lowest layer mesh model in the residual layer mesh model; determining a level of detail model based on the mesh refinement parent-child relationships and the lowest layer texture model.

[0007] In one embodiment of the present disclosure, the method comprises: The method further includes determining a threshold value of the side length of a mesh triangle of a mesh model of an arbitrary layer according to the set model parameters.

[0008] In another embodiment of the present disclosure, the step of determining a residual layer mesh model using a mesh refinement algorithm based on the top layer mesh model and set model parameters includes: The method includes a step of performing mesh refinement downward from the top layer mesh model using the mesh refinement algorithm based on a threshold side length of a mesh triangle of the mesh model of the arbitrary layer to obtain the residual layer mesh model.

[0009] In yet another embodiment of the present disclosure, the method comprises: The method further includes dividing mesh triangles in the mesh model of an arbitrary layer into at least one patch according to the subdivision parent-child relationship according to a root node.

[0010] In yet another embodiment of the present disclosure, the step of texture mapping the lowest layer mesh model to obtain the lowest layer texture model comprises: and determining a level of detail model based on the mesh refinement parent-child relationship and the lowest layer texture model by using a set texture mapping algorithm to texture map the lowest layer mesh model according to the at least one patch to obtain a lowest layer texture map file. determining sub-triangles of mesh triangles of a higher layer mesh model in the lowermost layer mesh model based on the mesh refinement parent-child relationship; determining texture coordinates of mesh triangles in the upper layer mesh model according to the texture coordinates of the sub-triangles; determining an upper layer texture model based on texture coordinates of mesh triangles in the upper layer mesh model and the texture map file of the lowest layer; and performing texture rearrangement on the upper layer texture model and the lowermost layer texture model to generate the level of detail model.

[0011] According to yet another aspect of an embodiment of the present disclosure, there is provided an apparatus for generating a level of detail model, the apparatus comprising: a mesh simplification module for performing a mesh simplification process on the target model to obtain a top layer mesh model; a mesh refinement module for determining a residual layer mesh model using a mesh refinement algorithm based on the top layer mesh model and set model parameters, and recording a refinement parent-child relationship between the upper layer mesh model and the lower layer mesh model; a texture mapping module for texture mapping the lowest layer mesh model to obtain a lowest layer texture model, the lowest layer mesh model being the lowest layer mesh model in the residual layer mesh model; and a texture model determination module for determining a level of detail model based on the mesh refinement parent-child relationship and the lowest layer texture model.

[0012] In one embodiment of the present disclosure, the device comprises: The method further includes a parameter determination module for determining a side length threshold of a mesh triangle of a mesh model of an arbitrary layer according to the set model parameters.

[0013] In yet another embodiment of the present disclosure, the mesh refinement module is used to perform mesh refinement downward from the top layer mesh model using the mesh refinement algorithm based on a threshold edge length of a mesh triangle of the mesh model of the arbitrary layer to obtain the residual layer mesh model.

[0014] In yet another embodiment of the present disclosure, the device comprises: The method further includes an image patch division module for dividing mesh triangles in the mesh model of an arbitrary layer into at least one patch according to a root node based on the mesh refinement parent-child relationship.

[0015] In yet another embodiment of the present disclosure, the texture mapping module is used to texture map the bottom layer mesh model according to the at least one patch using a set texture mapping algorithm to obtain a bottom layer texture map file.

[0016] In yet another embodiment of the present disclosure, the texture model determination module comprises: a first determination sub-module for determining sub-triangles of mesh triangles of a higher layer mesh model in the lowest layer mesh model based on the mesh refinement parent-child relationship; a second determination sub-module for determining texture coordinates of mesh triangles in the upper layer mesh model according to the texture coordinates of the sub-triangles; a third determination sub-module for determining an upper layer texture model based on the texture coordinates of mesh triangles in the upper layer mesh model and the texture map file of the lowest layer; and a generation sub-module for performing texture rearrangement on the upper layer texture model and the lowermost layer texture model to generate the level of detail model.

[0017] According to yet another aspect of an embodiment of the present disclosure, there is provided an electronic device, the electronic device comprising: a memory for storing a computer program; a processor for executing a computer program stored in the memory, and for implementing the method for generating a level of detail model when the computer program is executed.

[0018] According to yet another aspect of an embodiment of the present disclosure, there is provided a non-transitory computer-readable storage medium having stored thereon a computer program, the computer instructions of which, when executed by a processor, implement the above-described method for generating a level of detail model.

[0019] According to yet another aspect of an embodiment of the present disclosure, there is provided a computer program product including computer program instructions that, when executed by a processor, implements the above method for generating a level of detail model.

[0020] In the method, electronic device, and storage medium for generating a level of detail model according to the above-described embodiments of the present disclosure, a mesh simplification process is performed on a target model to obtain a top-layer mesh model, and then a mesh refinement algorithm is used to determine a residual layer mesh model based on the top-layer mesh model, thereby successfully constructing a mesh pyramid. A level of detail model can then be obtained by texture mapping the mesh model in the mesh pyramid. The embodiments of the present disclosure first maximize the simplification of the target model to obtain a top-layer mesh model, and then use a mesh refinement algorithm that does not change geometric accuracy. The mesh pyramid is successfully constructed. When texture mapping is performed on the mesh pyramid, the lowest-layer mesh model after mesh refinement is first texture mapped to obtain a lowest-layer texture model. Level of detail models with different texture resolutions can be obtained according to the refinement parent-child relationships between the mesh pyramids obtained by mesh refinement. The level of detail model constructed according to the embodiments of the present disclosure has a texture map with hierarchically sharpened texture details without changing geometric accuracy, and the lack of change in geometric accuracy can avoid "crack" defects.

[0021] The technical solution of the present disclosure will be further described in detail below through the drawings and examples.

[0022] The accompanying drawings, which form a part of the specification, illustrate embodiments of the present disclosure and, together with the description, serve to explain the principles of the disclosure.

[0023] The present disclosure may be more clearly understood by following the detailed description and by reference to the accompanying drawings, in which: [Brief explanation of the drawings]

[0024] [Figure 1] 1 is a flowchart of one embodiment of a method for generating a level of detail model of the present disclosure. [Figure 2A] 10 is a flowchart of another embodiment of a method for generating a level of detail model of the present disclosure. [Figure 2B] FIG. 1 is a schematic diagram of mesh simplification for a target model of the present disclosure. [Figure 2C] FIG. 10 is a schematic diagram of the effect of mesh refinement on a higher layer mesh model of the present disclosure. [Figure 2D] FIG. 10 is a schematic diagram of the effect after texture mapping a mesh model of the present disclosure. [Figure 3] 1 is a flowchart of texture mapping in the method for generating a level of detail model of the present disclosure. [Figure 4] FIG. 1 is a structural diagram of one embodiment of an apparatus for generating a level of detail model of the present disclosure. [Figure 5] FIG. 2 is a structural diagram of another embodiment of an apparatus for generating a level of detail model of the present disclosure. [Figure 6] 1 is a structural diagram of an electronic device according to an exemplary embodiment of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0025] Various exemplary embodiments of the present disclosure will be described in detail below with reference to the accompanying drawings. Note that the relative arrangement of components and steps, formulas and numerical values ​​described in these embodiments do not limit the scope of the present disclosure unless otherwise specified.

[0026] At the same time, it should be understood that for ease of explanation, the sizes of the parts shown in the accompanying drawings are not drawn to scale.

[0027] The following description of at least one exemplary embodiment is merely exemplary in nature and is in no way limiting of the disclosure and its applications or uses.

[0028] Techniques, methods and equipment known to those skilled in the relevant art may not be discussed in detail, but where appropriate, said techniques, methods and equipment should be considered part of the specification.

[0029] It should be noted that like numerals and letters indicate like items in the following accompanying drawings, so that once an item is defined in an accompanying drawing, no further discussion is necessary in subsequent accompanying drawings.

[0030] Embodiments of the present disclosure may be applied to electronic devices such as computer systems / servers, and are operational with numerous other general-purpose or special-purpose computing system environments or configurations. Examples of well-known computing systems, environments, and / or configurations suitable for use with electronic devices such as computer systems / servers include, but are not limited to, personal computer systems, server computer systems, thin clients, thick clients, handheld or laptop devices, microprocessor-based systems, set-top boxes, programmable consumer electronics, networked personal computers, small computer systems, large computer systems, and distributed cloud computing technology environments that include any of the above systems.

[0031] Electronic devices such as computer systems / servers may be described in the general context of computer system-executable instructions (e.g., program modules) executed by a computer system. Typically, program modules include routines, programs, target programs, components, logic, data structures, etc. that perform particular tasks or implement particular abstract data types. Computer systems / servers may also be implemented in distributed cloud computing environments in which tasks are performed by remote processing devices that are linked through a communications network. In a distributed cloud computing environment, program modules may be located in storage media, including storage devices, of local or remote computing systems.

[0032] Summary of the Disclosure The technical solution provided in the embodiments of the present disclosure is applied to generating an LOD model for an indoor scene where there are many planar structures. Because there are many planar structures, the model itself can be represented with fewer polygonal faces, and the "crack" defect caused by loading different levels of LOD patches during the display process can be avoided while maintaining geometric accuracy. Therefore, in the embodiments of the present disclosure, the mesh of the target model is first simplified to the utmost to obtain a top-layer mesh model, and then mesh refinement is performed to generate residual layer mesh models in the reverse direction, ensuring that the geometric accuracy of each layer does not change. When texture mapping is performed, texture maps with different resolutions and hierarchically clearer texture details can be generated for each layer according to the refinement parent-child relationship.

[0033] Illustrative Examples 1 is a flowchart of one embodiment of a method for generating a level of detail model of the present disclosure. The method for generating a level of detail model may be applied to electronic devices, and as shown in FIG. 1, the method for generating a level of detail model includes the following steps: In step 101, a mesh simplification process is performed on the target model to obtain a top layer mesh model.

[0034] In one embodiment, mesh simplification may be achieved using an edge collapse simplification algorithm. The edge collapse simplification algorithm is a type of geometric element removal method and will not be described in detail here. Note that for indoor scenes, due to the presence of a large amount of planar information, the simplification efficiency of the edge collapse simplification algorithm is very high. Referring to FIG. 2B , the effect of mesh simplification on a target model is shown. The graphic on the left side of the figure contains approximately 2 million polygons, while the simplified graphic on the right side contains approximately 100,000 polygons, resulting in a high overall simplification rate. In an embodiment of the present disclosure, after performing the mesh simplification process on the target model, a highly simplified model, i.e., a top-layer mesh model, can be obtained.

[0035] In step 102, based on the top layer mesh model and the set model parameters, a mesh refinement algorithm is used to determine a residual layer mesh model, and the refinement parent-child relationship between the upper layer mesh model and the lower layer mesh model is recorded.

[0036] In one embodiment, after performing mesh simplification on the target model, the top-layer mesh model can be further refined using a mesh refinement algorithm to construct a pyramid model. The geometric accuracy of the mesh models in each layer of the pyramid model constructed using the mesh refinement algorithm can be maintained unchanged. Referring to FIG. 2C , a schematic diagram of the effect of mesh refinement on a top-layer mesh model is shown, where the graphic on the left side of the figure is replaced by the graphic on the right side of the figure after mesh refinement. Mesh refinement is performed to accommodate subsequent texture mapping. The images used for texture mapping may not cover the entire scene, and each image may only show a portion of the scene. If a large triangle is present in the top-layer mesh triangles obtained by simplifying the target model, without mesh refinement, none of the images may show the entire triangle, potentially preventing effective texture mapping.

[0037] In one embodiment, the set model parameter may be the number of model layers, for example, a pyramid model to be constructed is set to a three-layer pyramid. In one embodiment, the pyramid model may be set to a model tree, for example, a model tree constructed as a quadtree or octree, and the number of layers of the pyramid model may also be determined based on the size of the leaf nodes. In one embodiment, the set model parameter may further include a side length threshold of mesh triangles of models in each layer, for example, if the side length threshold of mesh triangles of the top layer model is 1 m, the side length threshold of mesh triangles of each layer of lower layer models is the side length threshold of mesh triangles of each layer of higher layer models divided by 2.

[0038] In one embodiment, when the number of layers of a pyramid model and the mesh triangle edge length threshold of a mesh model of an arbitrary layer are determined according to the set model parameters, the mesh refinement algorithm can be used to perform mesh refinement downward from the top layer mesh model, so that the edge length of each triangle in the previous layer mesh is less than or equal to the mesh triangle edge length threshold, thereby obtaining the mesh model of the remaining layer.

[0039] In one embodiment, mesh refinement can be performed using a simple four-way division algorithm, or a policy of bisecting the long side. If the entire pyramid model is composed of n layers in the range [0, n-1], the n-1th layer is the most refined lowest layer mesh model, the 0th layer is the simplified top layer mesh model, the 1st layer is a refinement of the 0th layer model, the 2nd layer is a refinement of the 1st layer model, and so on. In this way, the lower layers are refinements of the upper layer models. Here, the residual layer mesh models are lower layer mesh models other than the top layer mesh model.

[0040] In one embodiment, when performing mesh refinement, it is also necessary to record the refinement parent-child relationship between the upper layer mesh model and the lower layer mesh model, i.e., to record which mesh triangle in the upper layer mesh model a mesh triangle in the lower layer mesh model is refined from.

[0041] In step 103, the lowest layer mesh model is texture mapped to obtain a lowest layer texture model, and the lowest layer mesh model is the lowest layer mesh model in the residual layer mesh model.

[0042] In one embodiment, based on the mesh subdivision parent-child relationship, the lowest layer mesh model is divided into at least one patch, and then texture expansion and texture mapping operations are performed according to the patch to obtain the lowest layer texture model.

[0043] The texture coordinates of the vertices of each mesh triangle in the lowest layer mesh model are normalized. By performing texture mapping according to the divided patches, it is possible to ensure that the corresponding texture coordinates of triangles with the same root node are spatially continuous within the texture map.

[0044] In step 104, a level of detail model is determined based on the mesh refinement parent-child relationship and the lowest layer texture model.

[0045] In one embodiment, the texture coordinates of the vertices of the upper layer mesh triangles can be directly obtained according to the subdivision correspondence relationship between the mesh triangles in the upper layer mesh model and the lower layer mesh model, and the texture coordinates of the vertices of the lower layer mesh model. These coordinates are also normalized. Due to the normalization of the texture coordinates, in a specific implementation, the texture map of the lower layer texture model can be directly scaled to obtain the texture map of the upper layer mesh model.

[0046] In one embodiment, the specific implementation of determining the level of detail model according to the mesh refinement parent-child relationship and the lowest layer texture model can be referred to the embodiment shown in FIG. 3, and will not be described in detail here.

[0047] In the above steps 101 to 104, a mesh simplification process is performed on the target model to obtain a top-layer mesh model. Then, a mesh refinement algorithm is used based on the top-layer mesh model to determine a residual layer mesh model, thereby successfully constructing a mesh pyramid. The mesh model in the mesh pyramid is then texture-mapped to obtain a level-of-detail model. In an embodiment of the present disclosure, the target model is first simplified to the maximum extent to obtain a top-layer mesh model, and then a mesh refinement algorithm that does not change geometric accuracy is used to successfully construct a mesh pyramid. When texture mapping the mesh pyramid, the lowest-layer mesh model after mesh refinement is first texture-mapped to obtain a lowest-layer texture model. Level-of-detail models with different texture resolutions can be obtained according to the refinement parent-child relationships between the mesh pyramids obtained by mesh refinement. The level-of-detail model constructed in the embodiment of the present disclosure has a texture map with hierarchically clear texture details without changing geometric accuracy, and the lack of change in geometric accuracy prevents "crack" defects.

[0048] To better illustrate the method for generating the level of detail model of the present application, another example is described below.

[0049] FIG. 2A is a flowchart of another embodiment of a method for generating a level of detail model of the present disclosure, FIG. 2B is a schematic diagram of mesh simplification for a target model of the present disclosure, FIG. 2C is a schematic diagram of the effect of mesh refinement for an upper layer mesh model of the present disclosure, and FIG. 2D is a schematic diagram of the effect after texture mapping of the mesh model of the present disclosure. This embodiment exemplarily describes how to generate a level of detail model, and as shown in FIG. 2A , includes the following steps: In step 201, a mesh simplification process is performed on the target model to obtain a top layer mesh model.

[0050] In one embodiment, step 203 is performed after the target model has undergone a mesh simplification process.

[0051] In step 202, a threshold value of the side length of the mesh triangle of the mesh model of an arbitrary layer is determined according to the set model parameters.

[0052] In one embodiment, the set model parameter may be the number of model layers, for example, a pyramid model to be constructed is set to a three-layer pyramid. In one embodiment, the pyramid model may be set to a model tree, for example, a model tree constructed as a quadtree or octree, and the number of layers of the pyramid model may also be determined based on the size of the leaf nodes. In one embodiment, the set model parameter may further include a side length threshold of the mesh triangles of the models in each layer, for example, if the side length threshold of the mesh triangles of the top layer model is 1 m, the side length threshold of the mesh triangles of each layer of the lower layer model is the side length threshold of the mesh triangles of each layer of the higher layer model divided by 2.

[0053] In step 203, the mesh refinement algorithm is used to perform mesh refinement downward from the top layer mesh model based on the threshold side length of the mesh triangle of the mesh model of the arbitrary layer to obtain the residual layer mesh model.

[0054] In one embodiment, mesh refinement can be performed using a simple four-way division algorithm or a bisection policy for the long side. For example, if the entire pyramid model is composed of n layers in the range [0, n-1], the (n-1)th layer is the most refined, lowest-level mesh model, the 0th layer is the simplified, top-level mesh model, the 1st layer is a refinement of the 0th layer model, and the 2nd layer is a refinement of the 1st layer model. Similarly, the lower layers are refinements of the upper-level models. Here, the residual layer mesh model is a lower-level mesh model other than the top-level mesh model. When performing mesh refinement, it is necessary to ensure that the edge length of each triangle in the mesh of the current layer is not greater than the mesh triangle edge length threshold to obtain the residual layer mesh model.

[0055] In step 204, based on the subdivision parent-child relationship, the mesh triangles in the mesh model of any layer are divided into at least one patch according to the root node.

[0056] In one embodiment, when mesh refinement is performed downward from the top layer mesh model, it is necessary to record the sub-triangles of each mesh triangle in the lower layer mesh model, and divide the mesh triangles in the mesh model of any layer into at least one patch according to the root node. For example, for mesh triangle 1 in the top layer (0th layer) mesh model, after mesh refinement, we can obtain mesh triangles "11, 12, 13, 14" in the first layer, and the mesh triangles "11, 12, 13, 14" in the first layer are divided into one patch because they have the same root node. By continuing to refine to lower layers, we can obtain mesh triangles "111, 112, 113, 114, 121, 122, 123, 124, 131, 132, 133, 134, 141, 142, 143, 144" in the second layer, and the mesh triangles "111, 112, 113, 114, 121, 122, 123, 124, 131, 132, 133, 134, 141, 142, 143, 144" in the second layer are divided into one patch because they have the same root node.

[0057] In step 205, at least one patch divided in the bottom layer mesh model is texture mapped to obtain a bottom layer texture model.

[0058] In one embodiment, any texture mapping algorithm can be used to obtain the texture coordinates of any mesh triangle in the lowest layer mesh model, thereby achieving texture mapping and obtaining a texture map file for the lowest layer. The texture map file for the lowest layer is one or more images, and several attribute information is added to the mesh triangles, including the vertices of each mesh triangle, the texture image that is the map source, and the vertex coordinates of the mesh triangle.

[0059] In concrete implementation, texture extension can be performed according to the divided patches in step 204, and then texture mapping can be performed according to at least one of the divided patches, and the texture coordinates of the same patch obtained in this way are also continuous on the image.

[0060] In step 206, a level of detail model is determined based on the mesh refinement parent-child relationship and the lowest layer texture model.

[0061] In one embodiment, the specific implementation of determining the level of detail model according to the mesh refinement parent-child relationship and the lowest layer texture model can be referred to the embodiment shown in FIG. 3, and will not be described in detail here.

[0062] Through the above steps 201 to 206, this embodiment discloses a specific implementation method of mesh refinement, which can realize subsequent effective texture mapping through mesh refinement, thereby ensuring that the level of detail model constructed in the embodiment of the present disclosure has a texture map with unchanged geometric precision and hierarchically clear texture details, and since the geometric precision does not change, the ``crack'' defect can be avoided.

[0063] FIG. 3 is a flowchart of one selected embodiment of a method for generating a level of detail model in an embodiment of the present disclosure. This embodiment exemplarily illustrates how to realize a level of detail model based on a lowest layer texture model and a mesh refinement parent-child relationship. As shown in FIG. 3 , the method includes the following steps: In step 301, sub-triangles of mesh triangles of a higher layer mesh model in the lowermost layer mesh model are determined based on the mesh refinement parent-child relationship.

[0064] In one embodiment, based on the mesh triangles and mesh refinement parent-child relationships in the upper layer mesh model, the vertices of the corresponding sub-triangles in the lower layer mesh model can be obtained.

[0065] In step 302, the texture coordinates of the mesh triangles of the upper layer mesh model are determined according to the texture coordinates of the sub-triangles.

[0066] In one embodiment, when texture mapping the lowest layer mesh model, the texture coordinates of the mesh triangles are obtained, and the texture coordinates of the vertices of the upper layer mesh triangles can be directly obtained according to the subdivision correspondence relationship of the mesh triangles in the upper layer mesh model and the lower layer mesh model, and the texture coordinates of the vertices of the lower layer mesh model.

[0067] In step 303, an upper layer texture model is determined based on the texture coordinates of the mesh triangles in the upper layer mesh model.

[0068] In steps 302-303, since the texture coordinates of the vertices of each mesh triangle in the lowest layer mesh model are generally normalized, the texture coordinates of the vertices of the upper layer mesh triangle can be directly obtained according to the subdivision correspondence relationship between the mesh triangles in the upper layer mesh model and the lower layer mesh model, and the texture coordinates of the vertices of the lower layer mesh model. The obtained texture coordinates of the vertices of the upper layer mesh triangle are also normalized. Due to the normalization of the texture coordinates, the texture map of the lower layer texture model can be directly scaled to obtain the texture map of the upper layer mesh model.

[0069] In step 304, texture rearrangement is performed on the upper layer texture model and the bottom layer texture model to generate the level of detail model.

[0070] In one embodiment, a texture remapping technique can be used to perform texture remapping on the upper layer texture model and the lower layer texture model, and a level of detail model can be generated by shrinking the texture image and reducing the resolution in the remapping process, which is a level of detail model of the texture. Referring to Figure 2D, the effect of texture mapping on a mesh model is shown, and it can be seen that the texture of the rendering effect achieved according to the technical proposal disclosed in this specification is hierarchically simplified and does not have "crack" defects.

[0071] Through the above steps 301 to 304, this embodiment can realize that in the texture mapping process, all sub-triangles of mesh triangles in the top layer mesh model with the same root node are in one texture package, thereby ensuring texture continuity. In addition, the upper layer model after texture mapping can be obtained by simply querying the correspondence relationship. Texture rearrangement can ensure that the generated level of detail model has the characteristics of unchanged geometric precision and hierarchically simplified texture, which not only ensures the effectiveness of the level of detail model but also improves rendering efficiency.

[0072] Corresponding to the above embodiment of the method for generating a level of detail model, the present disclosure further provides an embodiment corresponding to an apparatus for generating a level of detail model.

[0073] FIG. 4 is a structural diagram of one embodiment of an apparatus for generating a level of detail model of the present disclosure, which is applied to an electronic device, and includes the following modules, as shown in FIG. 4: The mesh simplification module 41 is used to perform mesh simplification processing on the target model to obtain the top layer mesh model.

[0074] The mesh refinement module 42 is used to determine a residual layer mesh model using a mesh refinement algorithm based on the top layer mesh model and the set model parameters, and to record the refinement parent-child relationship between the upper layer mesh model and the lower layer mesh model.

[0075] The texture mapping module 43 is used to texture map the lowest layer mesh model to obtain the lowest layer texture model, which is the lowest layer mesh model in the residual layer mesh model.

[0076] A texture model determination module 44 is used to determine a level of detail model based on the mesh refinement parent-child relationship and the lowest layer texture model.

[0077] 5 is a structural diagram of another embodiment of an apparatus for generating a level of detail model of the present disclosure, as shown in FIG. 4 , based on the embodiment shown in FIG. 4 , in one embodiment, the apparatus further includes the following modules: The parameter determination module 45 is used to determine the edge length threshold of the mesh triangle of the mesh model of any layer according to the set model parameters.

[0078] In one embodiment, the mesh refinement module 42 is used to perform mesh refinement downward from the top layer mesh model using the mesh refinement algorithm based on a threshold edge length of a mesh triangle of the mesh model of the arbitrary layer to obtain the residual layer mesh model.

[0079] In one embodiment, the device further includes the following modules: The image patch division module 46 is used to divide the mesh triangles in the mesh model of any layer into at least one patch according to the root node based on the subdivision parent-child relationship.

[0080] In one embodiment, the texture mapping module 43 is used to texture map the bottom layer mesh model according to the at least one patch using a set texture mapping algorithm to obtain a bottom layer texture map file.

[0081] In one embodiment, the texture model determination module 44: a first determination sub-module 441 for determining sub-triangles of mesh triangles of the upper layer mesh model in the lowest layer mesh model according to the mesh refinement parent-child relationship; a second determining sub-module 442 for determining texture coordinates of mesh triangles in the upper layer mesh model according to the texture coordinates of the sub-triangles; a third determining sub-module 443 for determining an upper layer texture model according to the texture coordinates of mesh triangles in the upper layer mesh model and the texture map file of the lowest layer; and a generation sub-module 444 for performing texture rearrangement on the upper layer texture model and the lowest layer texture model to generate the level of detail model.

[0082] The process for realizing the functions and effects of each unit in the above device can be specifically referred to the process for realizing the corresponding step in the above method, so repeated explanations will be omitted here.

[0083] The device embodiments essentially correspond to the method embodiments, and therefore, for relevant parts, reference may be made to the partial description of the method embodiments. The above-described device embodiments are merely illustrative. Units described as separate components may or may not be physically separated, and components displayed as units may or may not be physical units, i.e., they may be located in one place or distributed across multiple network units. Depending on actual needs, some or all of the modules therein may be selected to achieve the objectives of the technical solution of the present disclosure. Those skilled in the art can understand and implement the present invention without any creative effort.

[0084] Hereinafter, an electronic device according to an embodiment of the present disclosure, into which an apparatus for implementing a method according to an embodiment of the present disclosure may be integrated, will be described with reference to Fig. 6. Fig. 6 is a structural diagram of an electronic device according to an exemplary embodiment of the present disclosure. As shown in Fig. 6, the electronic device includes one or more processors 61, a memory 62 consisting of one or more computer-readable storage media, and a computer program stored in the memory and executable by the processor. Execution of the program in memory 62 can realize the above-described method for generating a level-of-detail model.

[0085] Specifically, in actual applications, the electronic device may further include components such as an input device 63 and an output device 64, and these components may be interconnected via a bus system and / or other form of connection mechanism (not shown). Those skilled in the art will understand that the structure of the electronic device shown in Figure 6 is not intended to limit the electronic device, and may include more or fewer components than those shown, or several components, or a different arrangement of components.

[0086] The processor 61 may be a central processing unit (CPU) or other form of processing unit with data processing and / or instruction execution capabilities, and may control other components in the electronic device to perform desired functions.

[0087] The memory 62 may store one or more computer program products, and the memory may include various forms of computer-readable storage media, such as volatile memory and / or non-volatile memory. Volatile memory may include, for example, random access memory (RAM) and / or high-speed cache memory (cache). Non-volatile memory may include, for example, read-only memory (ROM), a hard disk, flash memory, etc. One or more computer program products may be stored in the non-transitory computer-readable storage medium, and the processor 61 may execute the computer program products to realize the above-described methods and / or other desired functions for generating the level-of-detail models of the examples of the present disclosure.

[0088] In one example, the electronic device may further include an input device 63 and an output device 64, these components being interconnected via a bus system and / or other form of connection (not shown). The input device 63 may also include, for example, a keyboard, a mouse, etc.

[0089] The output device 64 can output various information such as measured distance information, direction information, etc. The output device 64 can include, for example, a display, a speaker, a printer, a communication network, and a remote output device connected thereto.

[0090] Of course, for simplicity, Fig. 6 shows only some of the components in the electronic device that are relevant to the present disclosure, and omits components such as buses, input / output interfaces, etc. In addition, the electronic device may further include other appropriate components depending on a specific application scenario.

[0091] In addition to the methods and devices described above, embodiments of the present disclosure may also be a computer program product including computer program instructions that, when executed by a processor, cause the processor to perform the method steps described in the "Example Methods" section above of this specification to generate implementation methods according to various embodiments of the present disclosure.

[0092] The computer program product may have program code for carrying out operations of embodiments of the present disclosure written in any combination of one or more programming languages, including object-oriented programming languages ​​such as Java, C++, and conventional procedural programming languages ​​such as "C" or similar programming languages. The program code may execute entirely on a user's computing device, partially on a user's computing device, as a separate software package, partially on a user's computing device, partially on a remote computing device, or entirely on a remote computing device.

[0093] Additionally, an embodiment of the present disclosure may be a non-transitory computer-readable storage medium storing computer program instructions that, when executed by a processor, cause the processor to perform the steps of the method for generating a level of detail model according to various embodiments of the present disclosure, as described above in the "Example Method" section of this specification.

[0094] The non-transitory computer-readable storage medium may be any combination of one or more readable media. The readable medium may be a readable signal medium or a readable storage medium. The readable storage medium may be, for example, but not limited to, an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system or device, or any combination thereof. More specific examples (a non-exhaustive list) of readable storage media include an electrical connection having one or more leads, a portable disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the above.

[0095] Although the basic principles of the present disclosure have been described above in conjunction with specific embodiments, the benefits, advantages, effects, etc. mentioned in the present disclosure are merely examples and are not limiting, and these benefits, advantages, effects, etc. should not be considered as being necessary for each embodiment of the present disclosure. Furthermore, the specific details disclosed above are merely for the purpose of facilitating illustration and understanding and are not limiting, and the specific details do not limit the present disclosure from being implemented using the specific details.

[0096] Each embodiment in this specification is described step by step, and in each embodiment, differences from other embodiments are mainly described, and identical or similar parts between embodiments can be mutually referenced. System embodiments basically correspond to method embodiments, so they are briefly described, and for related parts, partial descriptions of method embodiments can be referenced.

[0097] Those skilled in the art can understand that all or part of the steps for realizing the above method embodiments may be completed by hardware associated with program instructions, and the program may be stored in a computer-readable storage medium, and when the program is executed, the steps of the above method embodiments are performed. The storage medium includes various media that can store program code, such as ROM, RAM, magnetic disk, optical disk, etc.

[0098] The methods and apparatuses of the present disclosure may be implemented in many ways. For example, the methods and apparatuses of the present disclosure may be implemented by software, hardware, firmware, or any combination of software, hardware, and firmware. The order of steps for the methods is for illustrative purposes only, and unless otherwise specified, the steps of the methods of the present disclosure are not limited to the order specifically described above. Also, in some embodiments, the present disclosure may be implemented as a program recorded on a recording medium, which program includes machine-readable instructions for implementing the methods of the present disclosure. Therefore, the present disclosure also covers a recording medium having a program recorded thereon for executing the methods of the present disclosure.

[0099] The description of the present disclosure has been provided for purposes of illustration and description and is not intended to be exhaustive or to limit the disclosure to the precise form disclosed. Many modifications and variations will be apparent to those skilled in the art. The selection and description of the embodiments is provided to better explain the principles and practical applications of the present disclosure and to enable those skilled in the art to understand the disclosure and to design various embodiments with various modifications suitable for particular applications. [Explanation of symbols]

[0100] 1 mesh triangle 41 Mesh Simplification Module 42 Mesh Refinement Module 43 Texture Mapping Module 44 Texture model determination module 45 Parameter Determination Module 46 Image Patch Segmentation Module 61 processors 62 memory 63 Input Device 64 Output Devices 441 First Decision Submodule 442 Second Decision Submodule 443 Third Decision Submodule 444 Generation Submodule

Claims

1. 1. A method for generating a level of detail model, comprising: performing a mesh simplification process on the target model to obtain a top layer mesh model; determining a residual layer mesh model using a mesh refinement algorithm based on the top layer mesh model and the set model parameters, and recording a refinement parent-child relationship between the upper layer mesh model and the lower layer mesh model; a step of texture mapping the lowest layer mesh model to obtain a lowest layer texture model, the lowest layer mesh model being the lowest layer mesh model in the residual layer mesh model; determining a level of detail model based on the refinement parent-child relationships and the lowest layer texture model.

2. The method comprises: The method of claim 1 , further comprising determining a threshold edge length of a mesh triangle of a mesh model of an arbitrary layer according to the set model parameters.

3. determining a residual layer mesh model using a mesh refinement algorithm based on the top layer mesh model and set model parameters, 3. The method of claim 2, further comprising: using the mesh refinement algorithm to perform mesh refinement downward from the top layer mesh model based on a threshold side length of a mesh triangle of the mesh model of the arbitrary layer to obtain the residual layer mesh model.

4. The method comprises: The method of claim 1 , further comprising dividing mesh triangles in a mesh model of any layer into at least one patch according to a root node based on the subdivision parent-child relationship.

5. The step of texture mapping the lowest layer mesh model to obtain the lowest layer texture model includes:

5. The method of claim 4, further comprising the step of texture mapping the bottom layer mesh model according to the at least one patch using a set texture mapping algorithm to obtain a bottom layer texture map file.

6. determining a level of detail model based on the subdivision parent-child relationships and the lowest layer texture model; determining sub-triangles of mesh triangles of the upper layer mesh model in the lowermost layer mesh model based on the subdivision parent-child relationships; determining texture coordinates of mesh triangles in the upper layer mesh model according to the texture coordinates of the sub-triangles; determining an upper layer texture model based on texture coordinates of mesh triangles in the upper layer mesh model and the texture map file of the lowest layer; 6. The method of claim 5, further comprising performing texture rearrangement on the higher layer texture model and the lowest layer texture model to generate the level of detail model.

7. 1. An apparatus for generating a level of detail model, comprising: a mesh simplification module for performing a mesh simplification process on the target model to obtain a top layer mesh model; a mesh refinement module for determining a residual layer mesh model using a mesh refinement algorithm based on the top layer mesh model and set model parameters, and recording a refinement parent-child relationship between the upper layer mesh model and the lower layer mesh model; a texture mapping module for texture mapping the lowest layer mesh model to obtain a lowest layer texture model, the lowest layer mesh model being the lowest layer mesh model in the residual layer mesh model; a texture model determination module for determining a level of detail model based on the refinement parent-child relationships and the lowest layer texture model.

8. The device comprises: The apparatus of claim 7 , further comprising: a parameter determination module for determining a side length threshold of a mesh triangle in a mesh model of an arbitrary layer according to the set model parameters.

9. 9. The apparatus of claim 8, wherein the mesh refinement module is used to perform mesh refinement downward from the top layer mesh model using the mesh refinement algorithm based on a threshold side length of a mesh triangle of the mesh model of the arbitrary layer to obtain the residual layer mesh model.

10. The device comprises: The apparatus of claim 7 , further comprising an image patch division module for dividing mesh triangles in a mesh model of any layer into at least one patch according to a root node based on the subdivision parent-child relationship.

11. The apparatus of claim 10, wherein the texture mapping module is used to texture map the bottom layer mesh model according to the at least one patch using a set texture mapping algorithm to obtain a bottom layer texture map file.

12. The texture model determination module: a first determination sub-module for determining sub-triangles of mesh triangles of a higher layer mesh model in the lowest layer mesh model based on the subdivision parent-child relationship; a second determination sub-module for determining texture coordinates of mesh triangles in the upper layer mesh model according to the texture coordinates of the sub-triangles; a third determination sub-module for determining an upper layer texture model based on the texture coordinates of mesh triangles in the upper layer mesh model and the texture map file of the lowest layer; The apparatus of claim 11 , further comprising a generation sub-module for performing texture rearrangement on the higher layer texture model and the lowest layer texture model to generate the level of detail model.

13. An electronic device, a memory for storing the computer product; and a processor that executes the computer product stored in the memory, and that, when the computer product is executed, realizes the method according to any one of claims 1 to 6.

14. A non-transitory computer-readable storage medium having stored thereon computer instructions, the computer instructions, when executed by a processor, implementing the method of any one of claims 1 to 6.

15. A computer program product comprising computer program instructions for implementing the method of any one of claims 1 to 6 when executed by a processor.

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