WO2022105641A1 - Rendering method, device and system - Google Patents

Abstract

Provided are a rendering method, device and system. The rendering system comprises a rendering application serving end which is applied to the rendering system, and the rendering system further comprises a rendering application client, wherein the rendering application client is deployed on a terminal device, and the rendering application serving end is deployed on a remote rendering node. The method comprises: the rendering application serving end receiving a first angle of view; the rendering application serving end calling, according to the first angle of view, a rendering engine to search a valid grid set for a valid grid corresponding to the first angle of view; generating a rendering image according to the light intensity of the valid grid corresponding to the first angle of view, wherein the valid grid set is a set of valid grids corresponding to a preset set of angles of view, and the first angle of view belongs to the set of angles of view; and the rendering application serving end sending the rendering image to the rendering application client. By means of the method, the resources required for calculation can be effectively reduced.

Description

Rendering method, device and system technical field

The present application relates to the 3D field, and in particular, to a rendering method, device, and system.

Background technique

Rendering refers to the process of using software to generate images from a 3D model, where a 3D model is a description of a 3D object using a strictly defined language or data structure, including geometry, viewpoint, texture, and lighting information. The images are digital images or bitmap images. Rendering is a term similar to "an artist's rendering of a scene", and is also used to describe "the process of computing effects in a video editing file to produce the final video output".

However, in the prior art, rendering requires a very large amount of computation and consumes a lot of computing resources.

SUMMARY OF THE INVENTION

In order to solve the above problems, the present application provides a rendering method, device and system, which can effectively reduce the consumption of computing resources.

In a first aspect, a rendering method is provided, which is applied to a rendering application server of a rendering system, the rendering system further includes a rendering application client, the rendering application client is deployed on a terminal device, and the rendering application server is deployed For remote rendering nodes, the method includes:

The rendering application server receives the first perspective;

The rendering application server calls the rendering engine according to the first viewing angle to search for the valid grid corresponding to the first viewing angle in the valid grid set, and generates a rendered image according to the light intensity of the valid grid corresponding to the first viewing angle , wherein the valid grid set is a set of valid grids corresponding to a preset viewing angle set, and the first viewing angle belongs to the viewing angle set;

The rendering application server sends the rendering image to the rendering application client.

In some possible designs, the light intensity of the effective mesh is pre-computed and stored in the rendering application server.

In some possible designs, the valid grid corresponding to the first viewing angle is specifically: a grid that can be observed from a viewpoint corresponding to the first viewing angle, wherein the grid is a 3D model of the target scene obtained by dividing the surface.

In some possible designs, the valid grid set is a set composed of valid grids corresponding to each viewing angle in the viewing angle set.

In some possible designs, the perspective set is preset by the user on the rendering application server; the perspective set is obtained by the rendering application server according to historical perspective statistics of the rendering application; the perspective set is all It is predicted by the rendering application server based on the historical perspective of the rendering application.

In some possible designs, the material of the effective mesh includes a diffuse reflection material and an optical material, and in the case where the material of the effective mesh is a diffuse reflection material, the light intensity of the effective mesh includes a The ray intensity obtained by performing forward ray tracing on the grid; when the material of the effective grid is an optical material, the ray intensity of the effective grid includes the backward ray from the same specific angle as the angle of the first viewing angle Trace the resulting ray intensity.

In a second aspect, a rendering application server is provided, and the rendering application server includes: a receiving module, a rendering module, and a sending module;

The receiving module is configured to receive the first perspective sent by the rendering application client;

The rendering module is configured to call the rendering engine according to the first viewing angle to search for the valid grid corresponding to the first viewing angle in the valid grid set, and generate a rendered image according to the light intensity of the valid grid corresponding to the first viewing angle , wherein the valid grid set is a set of valid grids corresponding to a preset viewing angle set, and the first viewing angle belongs to the viewing angle set;

The sending module is configured to send the rendered image to the rendering application client.

In some possible designs, the valid grid corresponding to the first viewing angle is specifically: a grid that can be observed from a viewpoint corresponding to the first viewing angle, wherein the grid is a 3D model of the target scene obtained by dividing the surface.

In some possible designs, the valid grid set is a set composed of valid grids corresponding to each viewing angle in the viewing angle set.

In some possible designs, the perspective set is preset by the user on the rendering application server; the perspective set is obtained by the rendering application server according to historical perspective statistics of the rendering application; the perspective set is all It is predicted by the rendering application server based on the historical perspective of the rendering application.

In some possible designs, the material of the effective mesh includes a diffuse reflection material and an optical material, and in the case where the material of the effective mesh is a diffuse reflection material, the light intensity of the effective mesh includes a The ray intensity obtained by performing forward ray tracing on the grid; when the material of the effective grid is an optical material, the ray intensity of the effective grid includes the backward ray from the same specific angle as the angle of the first viewing angle Trace the resulting ray intensity.

In a third aspect, a rendering method is provided, which is applied to a rendering system, where the rendering system includes a rendering application client and a rendering application server, the rendering application client is deployed on a terminal device, and the rendering application server is deployed on A remote rendering node, the method includes:

The rendering application client sends the first perspective

The rendering application server receives the first viewing angle; according to the first viewing angle, the rendering engine is called to search for the valid grid corresponding to the first viewing angle in the valid grid set, and the valid grid corresponding to the first viewing angle is based on the first viewing angle. generating a rendered image based on the light intensity of the grid; sending the rendered image; wherein, the valid grid set is a set of valid grids corresponding to a preset viewing angle set, and the first viewing angle belongs to the viewing angle set;

The rendering application client receives the rendered image.

In some possible designs, the valid grid corresponding to the first viewing angle is specifically: a grid that can be observed from a viewpoint corresponding to the first viewing angle, wherein the grid is a 3D model of the target scene obtained by dividing the surface.

In some possible designs, the valid grid set is a set composed of valid grids corresponding to each viewing angle in the viewing angle set.

In some possible designs, the perspective set is preset by the user on the rendering application server; the perspective set is obtained by the rendering application server according to historical perspective statistics of the rendering application; the perspective set is all It is predicted by the rendering application server based on the historical perspective of the rendering application.

In some possible designs, the material of the effective mesh includes a diffuse reflection material and an optical material, and in the case where the material of the effective mesh is a diffuse reflection material, the light intensity of the effective mesh includes a The ray intensity obtained by performing forward ray tracing on the grid; when the material of the effective grid is an optical material, the ray intensity of the effective grid includes the backward ray from the same specific angle as the angle of the first viewing angle Trace the resulting ray intensity.

In a fourth aspect, a rendering system is provided, including a rendering application server, a rendering application client, and a rendering engine, the rendering application client is deployed on a terminal device, and the rendering application server and the rendering engine are deployed on a remote render node;

The rendering application server is used to receive a first view angle; according to the first view angle, the rendering engine is called to search for the valid grid corresponding to the first view angle in the valid grid set, and the valid grid corresponding to the first view angle is called according to the first view angle. generating a rendered image based on the light intensity of the grid; sending the rendered image; wherein, the valid grid set is a set of valid grids corresponding to a preset viewing angle set, and the first viewing angle belongs to the viewing angle set;

The rendering application client is configured to send the first viewing angle and receive the rendered image.

In some possible designs, the valid grid corresponding to the first viewing angle is specifically: a grid that can be observed from a viewpoint corresponding to the first viewing angle, wherein the grid is a 3D model of the target scene obtained by dividing the surface.

In some possible designs, the valid grid set is a set composed of valid grids corresponding to each viewing angle in the viewing angle set.

In some possible designs, the perspective set is preset by the user on the rendering application server; the perspective set is obtained by the rendering application server according to historical perspective statistics of the rendering application; the perspective set is all It is predicted by the rendering application server based on the historical perspective of the rendering application.

In some possible designs, the material of the effective mesh includes a diffuse reflection material and an optical material, and in the case where the material of the effective mesh is a diffuse reflection material, the light intensity of the effective mesh includes a The ray intensity obtained by performing forward ray tracing on the grid; when the material of the effective grid is an optical material, the ray intensity of the effective grid includes the backward ray from the same specific angle as the angle of the first viewing angle Trace the resulting ray intensity.

In a fifth aspect, a computing node is provided, the computing node includes a processor and a memory, and the processor executes a program in the memory, thereby performing the method according to any one of the first aspects.

In a sixth aspect, a computer-readable storage medium is provided, characterized by comprising instructions, when the instructions are executed on a computing node, the computing node causes the computing node to execute the method according to any one of the first aspects.

In the above solution, the rendering application server finds the corresponding valid grid from the valid grid set according to the first viewing angle, and calculates the rendered image according to the light intensity of the valid grid, which can effectively save more than traditional ray tracing rendering. computing resources.

Description of drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present application or the background technology, the accompanying drawings required in the embodiments or the background technology of the present application will be described below.

1A-1B are schematic structural diagrams of some rendering systems provided by the present application;

2 is a schematic structural diagram of observing a target scene from different angles involved in the present application;

3 is a schematic diagram of reverse ray tracing provided by the present application;

4A-4B are schematic diagrams of some grids provided by this application;

5 is a schematic diagram of a viewing angle of an observation target scene provided by the present application;

6 is a schematic diagram of N rays emitted by viewpoint E provided by the present application and M grids in the target scene for intersection;

7A-7D are schematic diagrams of some forward ray tracings provided by this application;

8 is a schematic diagram of the number of rays obtained by sampling per unit area provided by the present application;

9A-9B are schematic diagrams of reverse ray tracing rendering provided by the present application;

10 is a schematic diagram of the angle of reverse ray tracing rendering provided by the present application;

11 is a schematic diagram of the intersection of a light ray emitted from a viewpoint E and a three-dimensional model provided by the present application;

FIG. 12 is a flow interaction diagram of a rendering method provided by the present application;

FIG. 13 is a flow interaction diagram of another rendering method provided by the present application;

FIG. 14 is a schematic structural diagram of a rendering application server provided by the present application.

Detailed ways

Referring to FIG. 1A , FIG. 1A is a schematic structural diagram of a rendering system involved in the present application. The rendering system of the present application is used for a 2D image obtained by rendering a 3D model of a target scene through a rendering method, that is, a rendered image. The rendering method may include rasterization rendering, ray tracing rendering, and the like. The rendering system provided in FIG. 1A may include: a plurality of terminal devices 110 , a network device 120 and a remote rendering platform 130 . Specifically, the remote rendering platform 130 may be deployed on a public cloud. The remote rendering platform 130 and terminal devices are generally deployed in different data centers or even geographic areas.

The terminal device 110 may be a device that needs to display a rendered image, for example, a virtual reality device (virtual reality, VR) used for flight training, a computer used for virtual games, a smart phone used in a virtual mall, and the like, There is no specific limitation here. The terminal device can be a device with high configuration and high performance (for example, multi-core, high frequency, large memory, etc.), or a device with low configuration and low performance (for example, single core, low frequency, small memory, etc.) equipment. In a specific embodiment, the terminal device 110 runs an operating system and a rendering application client.

The network device 120 is used to transmit data between the terminal device 110 and the remote rendering platform 130 through a communication network of any communication mechanism/communication standard. The communication network may be a wide area network, a local area network, a point-to-point connection, etc., or any combination thereof.

The remote rendering platform 130 includes a plurality of rendering nodes, and each rendering node includes rendering hardware, an operating system, a rendering engine, and a rendering application server from bottom to top. The rendering hardware includes computing resources, storage resources, and network resources.

The computing resources can adopt a heterogeneous computing architecture, for example, a central processing unit (CPU) + graphics processing unit (GPU) architecture, CPU+AI chip, CPU+GPU+AI chip architecture, etc. , which is not specifically limited here. Storage resources can include memory and so on. Here, computing resources may be divided into multiple computing unit resources, storage resources may be divided into multiple storage unit resources, and network resources may be divided into multiple network unit resources. Therefore, the remote rendering platform 130 can freely combine resources according to the user's resource requirements on the basis of unit resources, so as to provide resources according to the user's needs. For example, the virtualized service can flexibly isolate mutually independent resources according to the user's needs to run the rendering engine and/or the rendering application server. Generally, virtualization services can isolate independent computing resources such as virtual machine (VM) services, bare metal server (BMS) services, and containers (containers). A rendering engine can be used to implement image rendering algorithms. The rendering engine allows the rendering application to call the rendering algorithm (pipeline) built into the rendering engine according to its interface to complete the image rendering. The rendering application server can be used to call the rendering engine to complete the rendering of the rendered image.

The rendering application client running on the terminal device 110 and the rendering application server running on the remote rendering platform 130 respectively constitute the front end and the back end of the rendering application. Among them, common rendering applications may include: game applications, VR applications, movie special effects, animation, and so on. The rendering application can perform real-time image rendering by invoking the rendering engine, thereby obtaining the rendered image.

In a specific implementation manner, the rendering application server and the rendering application client may be provided by a rendering application provider, and the rendering engine may be provided by a cloud service provider. For example, the rendering application can be a game application. The game application developer installs the game application server on the remote rendering platform provided by the cloud service provider, and the game application game developer provides the game application client through the Internet. Download it to the user and install it on the user's terminal device. In addition, cloud service providers also provide rendering engines, which can provide computing power for game applications. In another specific implementation, the rendering application client, the rendering application server and the rendering engine may all be provided by a cloud service provider.

In the cloud rendering system shown in FIG. 1B , a management device 140 is also included. The management device 140 may be a user's terminal device and a device provided by a third party other than the remote rendering platform 130 of the cloud service provider, or may be deployed on a public cloud together with the remote rendering platform 130 . For example, the management device 140 may be provided by a rendering application provider. The rendering application provider may manage the rendering application through the management device 140. For example, the rendering application provider may specify, through the management device 140, the quality parameters of the initial rendered image provided by the rendering application server to the rendering application client, and so on.

In a virtual scene in which multiple users participate, in order to make each user feel realistic, different users often need rendered images of the same target scene generated from different angles. As shown in FIG. 2 , assuming that the target scene is shown in (a) of FIG. 2 , when the first user using the terminal device 1 observes from the first perspective, the rendered image that needs to be generated is shown in (b) of FIG. 2 As shown, when a second user using the terminal device 2 observes from a second perspective, a rendered image that needs to be generated is shown in (c) of FIG. 2 . Then, the terminal device 1 and the terminal device 2 can independently perform ray tracing rendering on the target scene, thereby obtaining rendered images from different angles. specifically,

The terminal device 1 sends a first rendering request to the remote rendering platform 130 through the network device 120, and the remote rendering platform 130 invokes the rendering engine to independently perform ray tracing on the target scene using ray tracing rendering from the perspective of the first user according to the first rendering request, thereby A rendered image of the target scene generated from the perspective of the first user is obtained.

The terminal device 2 sends a second rendering request to the remote rendering platform 130 through the network device 120, and the remote rendering platform 130 invokes the rendering engine to independently perform ray tracing on the target scene using ray tracing rendering from the perspective of the second user according to the second rendering request, thereby A rendered image of the target scene generated from the second user's perspective is obtained.

However, there are a lot of repeated computations between the rendered image generated from the perspective of the first user and the rendered image generated from the perspective of the second user, thereby causing a lot of wasted computing resources.

The ray tracing rendering method adopted by the terminal device 1 and the terminal device 2 will be described in detail below. Ray-traced rendering is a rendering method that produces a rendered image by tracing the path of light entering a target scene along the path of light emitted from a camera's (or human eye's) viewpoint toward each pixel of the rendered image. The target scene includes a light source and a three-dimensional model. The core idea of ray tracing rendering is to trace rays backward from the viewpoint of the camera (or human eye) (when the viewpoint is determined, the angle of view is naturally determined). Since only the rays that finally enter the camera (or the human eye) are useful, backtracing rays can effectively reduce the amount of data.

As shown in FIG. 3 , it is assumed that the target scene has only one light source 311 and one opaque sphere 312 . A ray of light is emitted from the viewpoint E of the camera 313, projected on the pixel point O ₁ of the rendered image 314, and then continues to be emitted to a point P ₁ of the opaque sphere 312, and then reflected to the light source L, at this time, the point P ₁ The light intensity and color of pixel O ₁ determine the light intensity and color. Another ray from the viewpoint E of the camera 311 is projected to another pixel point O ₂ in the rendered image 314 , and then continues to a point P ₂ of the opaque sphere 312 , and is then reflected to the light source L, and the point There is an obstacle opaque sphere 312 between P ₂ and the light source L. At this time, the point P ₂ is located in the shadow of the opaque sphere 312, the light intensity of the pixel point O ₂ is zero, and the color is black.

It can be understood that in Figure 3, it is assumed that there is only one opaque sphere in the target scene. In practical applications, the target scene is far more complicated than Figure 3. For example, there may be multiple opaque objects and multiple transparent objects in the target scene at the same time. Therefore, , the ray will be reflected, refracted and transmitted multiple times, which makes the ray tracing very complicated and consumes a lot of computing resources. Moreover, in the above-mentioned embodiment, the rendering system only includes the terminal device 1 and the terminal device 2 as an example for description, but in practical applications, the number of terminal devices is far more than two, and the user's The viewing angles are often different. Therefore, as the number of users increases, the number of rendered images of different viewing angles that need to be generated also increases, and the amount of calculation is very large.

It is assumed that there are one or more light sources and one or more three-dimensional models in the target scene. The light produced by the light source strikes the 3D model. The light source may be a point light source, a line light source, or a surface light source, or the like. The shape of the three-dimensional model can be various, for example, it can be a sphere, a cone, a curved object, a plane object, an object with irregular surface, and so on.

Divide the surface of the 3D model in the target scene into a large number of meshes. That is, the mesh is a partial area of the surface of the three-dimensional model in the scene. The shapes of the meshes of the three-dimensional models with different shapes may be different, for example, the shapes of the meshes of the sphere and the meshes of the curved objects may be completely different. Grids can have unique grid IDs. The grid will be described below with reference to specific embodiments.

As shown in Figure 4A, taking the 3D model as a sphere as an example, the grid can be represented as the center point P(r, θ,

) and the center point P(r, θ,

) is an approximate square with slightly bulging sides on the surface of the sphere formed by the points in the neighborhood. A three-dimensional orthogonal coordinate system is constructed with the center of the sphere as the origin, wherein the three-dimensional orthogonal coordinate system includes an x-axis, a y-axis and a z-axis. Among the coordinates of the center point P, r represents the length of the line segment OP from the center of the sphere O to the center point P, and θ represents the angle between the line segment OP and the positive z-axis,

Expressed as the angle between the projection of the line segment OP on the xoy plane and the x-axis. In a specific embodiment, _n center points P ₁ , P ₂ , . . . , P _n can be uniformly set on the sphere _{. j} and the center point P _i belong to the same grid.

As shown in FIG. 4B , taking the 3D model as a curved object as an example, the mesh can be represented as a square on the curved surface represented by P(u, t). A two-dimensional orthogonal coordinate system is constructed with a set origin of the surface, wherein the coordinate system includes the u-axis and the t-axis. u represents the offset in one direction of the origin set for the surface, t represents the offset in another orthogonal direction, and P(u, t) represents the four vertices in the (u, t) coordinate system as shown in Figure 4B composed of blocks.

It can be understood that the above-mentioned shapes of the meshes are only used as specific examples, and in practical applications, the meshes may also have other shapes, such as hexagons, etc., which are not specifically limited here. In addition, the size of the grid can be set as required. When the accuracy requirement is higher, the grid size can be set smaller, and when the accuracy requirement is lower, the grid size can be set larger.

Determine the set of viewpoints from which the user observes the target scene. The perspective set may include one perspective or multiple perspectives. As shown in Figure 5, for a single viewpoint E, the viewing angle of the viewpoint E can be expressed as (P, θ), where P is the vertical distance from the viewpoint E to the rendered image, and θ is the viewpoint E to the center of the rendered image The angle between the line connecting point O and the horizontal line. The perspectives in the perspective set may be various perspectives of the same user at different moments, various perspectives of different users at the same moment, various perspectives of multiple users at different moments, and so on. Among them, the method for determining the view set includes at least the following:

In the first way, the set of views may be preset. That is to say, each view angle in the view angle set is preset by the user. For example, the remote rendering platform can collect various perspectives of users of different terminal devices at the same time, and set them as a perspective set in advance. Alternatively, when the rendering application is a game application, the game application provides a specific game path, and the remote rendering platform can collect various perspectives of the user in the specific game path, and preset them as a perspective set.

In the second approach, the set of views may be statistically derived. For example, a plurality of historical perspectives may be counted, and historical perspectives whose occurrence probability is greater than a preset threshold may be set as a perspective set. Here, a normal distribution, a Poisson distribution, etc. may be used to perform statistics on multiple historical perspectives.

In a third approach, the set of views can be predicted. For example, when the rendering application is a game application, the subsequent game path can be predicted by a prediction algorithm according to the existing game path given by the game application, and the possible viewing angles of the predicted game path can be set as the viewing angle set. Here, the prediction algorithm may include: decision tree algorithm, artificial neural network, support vector machine and so on.

It should be understood that the above method for determining the perspective set is only a specific example. In practical applications, the perspective set can also be determined in an iterative manner. For example, when the rendering application is a game application, if the game scene is switched, each The perspective of each game scene changes, so each game scene's perspective collection is iterated over each game scene switch.

K valid grids corresponding to the viewing angle set are determined from the plurality of grids. Taking a viewing angle in the viewing angle set as an example, the valid grid corresponding to the viewing angle is specifically the grid that can be observed by the viewpoint corresponding to the viewing angle. As shown in FIG. 6 , starting from the viewpoint E corresponding to the viewing angle, light rays with the number of samples per unit pixel are emitted to each pixel of the rendered image. That is, the total number of rays emitted from this viewpoint E = the width pixels of the rendered image * the height pixels of the rendered image * the rays of the number of samples per unit pixel. It should be noted that, for the convenience of observation, FIG. 6 only shows one ray emitted from the viewpoint E to the four corner pixels of the rendered image, and other rays are omitted. N rays emanating from this viewpoint E are intersected with M meshes in the target scene. If the i-th ray intersects the j-th grid, the j-th grid is a valid grid, where 1≤i≤N, 1≤j≤M, i, j, N, M are all positive integers . Conversely, if the rays generated by any viewing angle in the viewing angle set do not intersect the jth grid, then the jth grid is an invalid grid. To reduce the amount of data, valid grids only need to be stored once. For example, if the i-th ray intersects the j-th grid, and the i+1-th ray also intersects the j-th grid, then the j-th grid only needs to be stored once. It needs to be stored once, and invalid meshes do not need to be stored. When storing the valid grid, only the grid ID of the valid grid and the ID of the 3D model where the valid grid is located can be stored, or the grid ID of the valid grid and the ID of the 3D model where the valid grid is located can be stored. , the spatial coordinates of the effective grid, the direction of rays entering the effective grid, and so on.

Materials for effective meshes can include diffusely reflective materials as well as optical materials. Among them, the diffuse reflection material is usually a material with a relatively rough surface, such as cloth, paper, wood, and rock. Optical materials are usually materials with relatively smooth surfaces, or transparent materials, such as lake surfaces, mirror surfaces, and dewdrops. Taking the kth effective mesh as an example, if the kth effective mesh is a diffuse material, then from the light source in the target scene, light is emitted to the effective mesh, and forward ray tracing is performed on the light; The k-th effective meshes are optical materials, and reverse ray tracing is performed on the k-th effective meshes from multiple angles. in,

Forward ray tracing refers to starting from the light source and forward tracing the transfer process of rays in the target scene. There are mainly four scenarios in forward ray tracing: reflection, refraction, transmission, and direct illumination, which will be described below with reference to FIGS. 7A-7D and specific embodiments, respectively.

As shown in FIG. 7A , when it is assumed that the target scene is a reflection scene, it is assumed that the target scene has only one light source 411 , an opaque sphere 412 and an opaque sphere 413 . A ray of light is emitted from the light source 411, projected onto a point P1 _of the opaque sphere 412, and then reflected onto _an effective grid whose center point is the point Q1 of the opaque sphere 413. Therefore, the light intensity generated by the light source 411 on the point P ₁ of the opaque sphere 412 can be calculated by the local light illumination model, and then, after the light is reflected by the opaque sphere 412, the center point of the opaque sphere 413 is the point Q ₁ The intensity of light produced on the effective mesh of .

As shown in FIG. 7B , when it is assumed that the target scene is a refraction scene, it is assumed that the target scene has only one light source 421 , a transparent sphere 422 and an opaque sphere 423 . _A ray of light from light source 421 is projected onto a point P2 of transparent sphere 422, and then refracted onto an effective grid of opaque sphere 423 whose center is point _Q2 . Therefore, the intensity of the light generated by the light source 421 at the point P ₂ of the transparent sphere 422 can be calculated through the local light illumination model, and then, after the light is refracted by the transparent sphere 422, the center point of the opaque sphere 423 is the point Q ₂ The intensity of light produced on the effective mesh of .

As shown in FIG. 7C , when the target scene is assumed to be a transmissive scene, it is assumed that the target scene has only one light source 431 , a transparent thin body 432 and an opaque sphere 433 . A ray of light is emitted from the light source 421, projected to a point _P3 of the thin transparent body 432, and then transmitted to an effective grid having a center point of the opaque sphere 433 at point _Q3 . Therefore, the light intensity of the light generated by the light source 431 at the point _P3 of the transparent thin body 432 can be calculated by the local light illumination model, and then, after the light is transmitted by the transparent thin body 432, the center point of the opaque sphere 433 is set as a point The intensity of light produced on the effective grid of Q ₃ .

As shown in FIG. 7D , when it is assumed that the target scene is a direct scene, it is assumed that the target scene has only one light source 441 and an opaque sphere 443 . A ray of light is emitted from light source 441 and projected onto an effective grid of opaque sphere 443 centered at point _Q4 . Therefore, the light intensity generated by the light source 441 on the effective grid whose center point is the point _Q4 of the opaque sphere 443 can be calculated by the local light illumination model.

However, the reflection scene in FIG. 7A , the refraction scene in FIG. 7B , the transmission scene in FIG. 7C and the direct scene in FIG. 7D are the simplest scenes. 7D is more complicated. For example, there may be multiple opaque objects and multiple transparent objects in the target scene at the same time. Therefore, the light will be reflected, refracted and transmitted multiple times. In addition, there may be more than one light source, but two or more.

Since the number of rays is infinite and computing resources are limited, it is usually impossible to perform forward ray tracing on all rays, so some rays need to be sampled.

When sampling the rays of forward ray tracing, the parameters involved in the sampling mainly include the number of samples per unit space and the number of ray bounces (Bounce) and so on. The following will take the sample per unit area (SPUA) and the number of light bounces as examples for a detailed introduction.

SPUA can be defined as the number of rays sampled per unit area. Taking the light source L as an example, a spherical surface S is constructed with the light source L as the center, and the spherical surface S is divided into a plurality of unit areas. Then, SPUA is equal to the amount of light generated by the light source L that passes through the unit area A. In theory, the number of rays generated by the light source L passing through a unit area is infinite. However, in the actual tracking process, it is impossible to trace all the rays, and only part of the limited rays can be traced. Here, the larger the number of SPUAs, the higher the number of rays traced, and the better the image quality, however, the greater the amount of computation. Conversely, the smaller the number of SPUAs, the lower the number of rays traced and the poorer the image quality, however, the less computation.

The number of ray bounces is the sum of the maximum number of reflections and refractions traced to the ray before the ray's forward tracing is terminated. Because in complex scenes, rays will be reflected and refracted multiple times. In theory, the number of times the rays are reflected and refracted can be infinite. However, in the actual tracking process, it is impossible to trace the rays infinitely. Therefore, some tracking termination conditions need to be given. In the application, there can be the following termination conditions: the light will decay after many times of reflection and refraction, and the light contribution to the light intensity of the viewpoint is very small; or, the number of ray bounces, that is, the tracking depth is greater than a certain value. Here, the more times the ray bounces, the more effective rays that can be tracked, the better the refraction effect between multiple transparent objects, the more realistic, and the better the image quality, but the greater the amount of computation. On the contrary, the less the number of ray bounces, the less effective rays that can be traced, the worse the refraction effect between multiple transparent objects, the more distorted, and the worse the image quality, but the less computation.

It can be understood that the above sampling parameters are only used as specific examples. In practical applications, other sampling parameters may also be used, which are not specifically limited here.

During forward ray tracing, rays may be passed to valid meshes or to invalid meshes. For example, a ray might pass from a valid mesh to an invalid mesh, and then from invalid mesh to valid mesh; or, a ray might pass from valid mesh to invalid mesh. If it is passed to a valid grid, the ray intensity generated by the ray in the valid grid needs to be counted; if it is passed to an invalid grid, there is no need to count the ray intensity generated by the ray in the invalid grid. .

Reverse ray-traced rendering is the process of passing rays into the target scene to light sources by tracing rays entering a valid mesh of a 3D model from a specific angle. The above-mentioned light rays obtained by reverse tracing from a specific angle can only be viewed by the human eye or the camera at the specific angle. Therefore, in order to achieve a full field of view, it is necessary to perform reverse ray tracing from multiple specific angles. The core idea of reverse ray traced rendering is to trace rays backward from the rays entering the valid mesh. There are mainly two scenarios of reflection and refraction in reverse ray tracing rendering, which will be described below with reference to specific embodiments.

As shown in FIG. 9A , when the target scene is a reflective scene, it is assumed that the target scene has only one light source 511 and one opaque sphere 512 . A ray of light is emitted from a specific angle, projected onto a point P ₁ of a valid grid of opaque sphere 512 , and then reflected to light source 511 . At this time, the light intensity of the light generated by the light source 511 on the effective grid of the opaque sphere 512 can be calculated by the local light illumination model.

As shown in FIG. 9B , when the target scene is a refraction scene, it is assumed that the target scene has only one light source 521 and one transparent sphere 522 . A ray is emitted from a specific angle, projected to a point P ₂ on an effective grid of the transparent sphere 522, then refracted to another point Q ₂ of the transparent sphere 522, and then refracted to the light source L. At this time, it can be Calculate the intensity of the light generated by the light source 521 at point Q ₂ through the local light illumination model, and then calculate the light generated on the effective grid with the center point P ₂ when the light is refracted from point Q ₂ to point P ₂ strength.

However, the reflection scene in Fig. 9A and the refraction scene in Fig. 9B are the simplest scenes. Fig. 9A assumes that there is only one opaque sphere in the target scene, and Fig. 9B assumes that there is only one transparent sphere in the target scene. In practical applications, the target scene is far more complex than Figure 9A to Figure 9B. For example, there may be multiple opaque objects and multiple transparent objects in the target scene at the same time. Therefore, the light will be reflected, refracted and transmitted multiple times, resulting in Ray tracing becomes very complex and consumes a lot of computing resources.

As shown in Figure 10, there are also differences in the light converged by different angles on the same effective grid, especially for optical materials, the difference will be very obvious. Each effective grid has an open hemispherical space facing its normal direction, and rays entering this hemispherical space can be expressed as taking the effective grid center P as the end point and taking any point O on the spherical surface of the hemispherical space (for example, O ₁ , O ₂ or O ₃ ) as the starting point. The space is continuous, but we can perform reverse ray tracing for different direction angles of each effective grid according to the computing power and accuracy requirements. The direction angle here refers to the (θ, π), where 0<θ<180, 0<π<360. Therefore, the above-mentioned specific angle can be any direction angle in the hemispherical space. Since the number of rays is infinite and the computing resources are limited, it is usually impossible to perform reverse ray tracing on all rays, so some rays need to be sampled. When sampling the rays of reverse ray tracing, the parameters involved in the sampling mainly include the number of samples per effective grid and the number of ray bounces, etc.

Assume that the set of effective meshes in the target scene includes a effective meshes T ₁ , T ₂ ,...,T a for diffuse reflective materials, and _b effective meshes T ₁ ,T ₂ ,...,T _b for optical materials , then the forward ray tracing is performed on the effective grids T ₁ , T ₂ ,...,T _a of a diffuse reflection materials, and the effective grids T ₁ , T ₂ , ... of b optical materials are respectively from k specific angles. , T _b performs reverse ray tracing.

After the forward ray _tracing is _performed , the forward ray intensities _{F 1 , F 2} , .

After performing reverse ray tracing on the effective grids T ₁ , T ₂ ,...,T _b of the b optical materials respectively from the first specific angle, the effective grid T ₁ of the b optical materials from the first specific angle can be obtained. ,T ₂ ,...,T _b respectively the first reverse ray intensities obtained by reverse ray tracing

After performing reverse ray tracing on the effective grids T ₁ , T ₂ ,..., T _b of the b optical materials respectively from the second specific angle, the effective grid T ₁ of the b optical materials from the second specific angle can be obtained. ,T ₂ ,…,T _b are the second reverse ray intensities obtained by reverse ray tracing respectively

…;

After performing reverse ray tracing on the effective grids T ₁ , T ₂ ,...,T _b of the b optical materials from the k-th specific angle, the effective grid T ₁ of the b optical materials from the k-th specific angle can be obtained. ,T ₂ ,…,T _b are the k-th reverse ray intensities obtained by reverse ray tracing respectively

The forward light intensity F ₁ , F ₂ ,...,F _a , the first reverse light intensity

second reverse ray intensity

The k-th reverse ray intensity

Stored as effective surface light emission field storage. In order to reduce the space required for storing the effective surface light emission field, the effective surface light emission field may be stored in a sparse matrix manner.

It can be understood that the above-mentioned effective surface light emission field is only a specific example. In practical applications, on the basis of the above example, forward ray tracing can also be performed on b optical materials, and the forward ray tracing obtained by the forward ray tracing can be performed. The light intensities F ₁ , F ₂ ,...,F _b and the first reverse light intensity respectively

second reverse ray intensity

The k-th reverse ray intensity

Superposition is performed to obtain an effective surface light emission field and so on.

When observing the target scene from different perspectives, the projected intersection method can be used to propose the corresponding data from the pre-calculated effective surface light emission field, so as to quickly obtain the effective grid set that can be observed from the perspective, and finally Generate the desired rendered image. The following will describe in detail how to obtain the set of object surfaces that can be observed by the user with reference to FIG. 9 and related specific embodiments.

As shown in FIG. 11 , it is assumed that the camera 611 (or the human eye) observes the target scene from the perspective corresponding to the viewpoint E, and the rendered image 612 generated by the observation has m pixels.

First, a ray is emitted from the viewpoint E and projected onto the first pixel of the rendered image 612, and then continues to be projected onto the first grid of the 3D model in the target scene, if the first grid is diffuse If the reflective material is used, the forward light intensity of the first grid is used as the light intensity of the first pixel. If the first grid is an optical material, the first incident angle at which the light enters the first grid is determined, The light intensity corresponding to the matching specific angle of the first grid is searched according to the first incident angle, and the corresponding light intensity is used as the light intensity of the first pixel point.

Then, a ray is emitted from the viewpoint E, projected on the second pixel of the rendered image 612, and then continues to be projected on the second grid of the three-dimensional model in the target scene, if the second grid is diffuse If the reflective material is used, the forward light intensity of the second grid is used as the light intensity of the second pixel point, and if the second grid is an optical material, the second incident angle at which the light enters the second grid is determined, And according to the second incident angle, the light intensity corresponding to the matching specific angle of the second grid is searched, and the corresponding light intensity is used as the light intensity of the second pixel point.

…;

Finally, a ray is emitted from the viewpoint E and projected to the mth pixel of the rendered image 612, and then continues to be emitted to the mth grid of the 3D model in the target scene, if the mth grid is diffuse If the reflective material is used, the forward light intensity of the m-th grid is taken as the light intensity of the m-th pixel; if the m-th grid is an optical material, the m-th incident angle of the light entering the m-th grid is determined, And according to the mth incident angle, the light intensity corresponding to the matching specific angle of the mth grid is searched, and the corresponding light intensity is used as the light intensity of the mth pixel point.

So far, the light intensities of m pixels have been determined, and the rendered image 612 has been determined.

It should be noted that the matching of the first incident angle with the specific angle of the first grid includes: the first incident angle is the same as the specific angle of the first grid, or the difference between the first incident angle and the specific angle of the first grid The difference is smaller than the preset threshold, which is not specifically limited here. The matching between the second incident angle and the specific angle of the second grid is also similar to the matching of the m-th incident angle with the specific angle of the m-th grid, which will not be described here.

For the sake of simplicity, the above-mentioned embodiment corresponding to FIG. 11 is described by taking the number of samples per pixel (Sample per pixel, Spp) equal to 1 as an example, wherein, SPP can be defined as the number of rays obtained by sampling each pixel, but, in In practical applications, in order to improve the quality of the rendered image, the value of SPP is usually made larger.

In the above scheme, for the effective grids T ₁ , T ₂ ,...,T _b of b optical materials, if the viewing angle position-based rendering scheme of this scheme is not adopted, then the upper limit of the effective network T _i of each optical material needs to be calculated. The hemisphere emits rays for reverse tracing, assuming the angle of the emitted rays (θ, π), where 0<θ<180, 0<π<360, a ray is emitted every 1 degree, and a total of θ*π=64800 is required. Rays, an effective network of b optical materials requires 64800b rays, that is, 64800b reverse ray tracings are required. However, if the rendering scheme based on the viewing angle position of this scheme is adopted, assuming that the number of viewing angle positions is k, and each optical material needs to emit at most k different optics, then the effective network of b optical materials only needs k*b rays at most, That is, you need to do kb reverse ray tracing. When k<<64800, the number of reverse ray tracing can be effectively reduced. Moreover, in order to render the image more accurately, each optical material network needs to emit more fine-grained rays, that is, each ray material network may emit more than 64800 rays. In this case, the proposed scheme emits at most k rays for each effective network of optical materials, thus greatly reducing the amount of data computation.

Referring to FIG. 12, FIG. 12 is a flowchart interaction diagram of a rendering method provided by the present application. The rendering method of this embodiment can be applied to the rendering system shown in FIG. 1A , and the method includes:

S101: The rendering application client of the terminal device sends the first view angle to the network device. Correspondingly, the network device receives the first view angle sent by the rendering application client of the terminal device.

In a specific embodiment of the present application, the first viewing angle may be a single viewing angle or multiple viewing angles. For example, the first viewing angle may be the angle at which the user of the rendering application client is currently viewing the game, or the viewing angle of the rendering application client. Multiple angles of the game path the user is playing, etc.

S102: The network device sends the first perspective to the rendering application server of the remote rendering platform. Correspondingly, the rendering application server of the remote rendering platform receives the first perspective sent by the network device.

S103: The rendering application server of the remote rendering platform invokes the rendering engine according to the first view angle to search for the valid grid corresponding to the first view angle in the valid grid set.

In a specific embodiment of the present application, the valid grid set is a subset formed by valid grids corresponding to each viewing angle in the viewing angle set in the grid set. That is, the effective grid set is generally smaller than the grid set. The grid set is a set composed of the grids. For the content of the perspective set, please refer to the introduction about the perspective set above, which will not be described here. The grid is obtained by dividing the surface of the 3D model in the target scene. For the definition of the grid, please refer to the above. 4A-4B and related descriptions are not further described here.

In a specific embodiment of the present application, the effective grid corresponding to the first viewing angle is specifically: a grid that can be observed from a viewpoint corresponding to the first viewing angle. After receiving the first viewing angle, the remote rendering platform determines that the first viewing angle belongs to the viewing angle set. Here, the remote rendering platform has pre-stored the correspondence between each viewing angle in the viewing angle set and the valid grid. For details, please refer to the above Determining the K valid grids corresponding to the viewing angle set from the multiple grids above. statement. Therefore, after the remote rendering platform determines that the first viewing angle belongs to the viewing angle set, the remote rendering platform can quickly obtain a valid mesh set observable from the first viewing angle by using a projective intersection method. For the content of the projective intersection method, reference may be made to FIG. 11 and related descriptions, which will not be described here again.

S104: The rendering application server of the remote rendering platform invokes the rendering engine to generate a rendered image according to the light intensity of the effective grid corresponding to the first viewing angle.

In a specific embodiment of the present application, the remote rendering platform has previously stored the light intensity of the effective grid corresponding to each viewing angle. Obviously, the material of the effective grid includes a diffuse reflection material and an optical material, and in the case where the material of the effective grid is a diffuse reflection material, the light intensity of the effective grid includes forwarding the effective grid. The light intensity obtained by ray tracing; when the material of the effective mesh is an optical material, the light intensity of the effective mesh includes the light intensity obtained by reverse ray tracing from each specific angle. Here, for the content of forward ray tracing and reverse ray tracing, please refer to the relevant content of forward ray tracing involved in FIGS. 7A-7D above, and the introduction of the relevant content of reverse ray tracing involved in FIGS. 9A-9B above. , which will not be described here.

In a specific embodiment of the present application, the remote rendering platform acquires the light intensity of the effective grid corresponding to the first viewing angle according to the first viewing angle. The effective grids corresponding to the first viewing angle include at least three cases: In the first case, the materials of the effective grids corresponding to the first viewing angle are all diffuse reflection materials. The ray intensity obtained by ray tracing is sufficient. In the second case, the materials of the effective grids corresponding to the first viewing angle are all optical materials. In this case, it is only necessary to obtain these effective grids and perform reverse ray tracing through the first viewing angle to obtain the light intensity. In the third case, the materials of the effective grid corresponding to the first viewing angle include both diffuse reflective materials and optical materials. In this case, it is necessary to obtain the effective grids whose materials are diffuse reflective materials through forward ray tracing. Light intensity, obtains the light intensity by performing reverse ray tracing from the first viewing angle of an effective grid whose material is an optical material.

S105: The rendering application server of the remote rendering platform sends the rendered image to the network device. Correspondingly, the network device receives the rendered image sent by the rendering application server of the remote rendering platform.

S106: The network device sends the rendered image to the rendering application client of the terminal device. Correspondingly, the rendering application client of the terminal device receives the rendered image sent by the network device.

For the sake of simplicity, the embodiment shown in FIG. 12 is not described in detail. For details, please refer to FIGS. 1A-1B, 2-3, 4A-4B, 5-6, and 7A- Fig. 7D, Fig. 8, Fig. 9A-Fig. 9B, Fig. 10-Fig. 11 and related descriptions, which are not further described here.

Referring to FIG. 13 , FIG. 13 is a flowchart interaction diagram of a rendering method provided by the present application. The rendering method of this embodiment can be applied to the rendering system shown in FIG. 1B , and the method includes:

S201: The management device sends the first view angle to the network device. Correspondingly, the network device receives the first view angle sent by the management device.

In a specific embodiment of the present application, the first viewing angle may be a single viewing angle or multiple viewing angles. For example, the first viewing angle may be the current viewing angle of the game by the user of the rendering application client of the terminal device, or the terminal The device's rendering of multiple angles of the game path played by the user of the application client, etc.

S202: The network device sends the first perspective to the rendering application server of the remote rendering platform. Correspondingly, the rendering application server of the remote rendering platform receives the first perspective sent by the network device.

S203: The rendering application server of the remote rendering platform invokes the rendering engine according to the first view angle to search for the valid grid corresponding to the first view angle in the valid grid set.

S204: The rendering application server of the remote rendering platform invokes the rendering engine to generate a rendered image according to the light intensity of the effective grid corresponding to the first viewing angle.

S205: The rendering application server of the remote rendering platform sends the rendered image to the network device. Correspondingly, the network device receives the rendered image sent by the rendering application server of the remote rendering platform.

S206: The network device sends the rendered image to the rendering application client of the terminal device. Correspondingly, the rendering application client of the terminal device receives the rendered image sent by the network device.

For the sake of simplicity, the embodiment shown in FIG. 12 is not described in detail. For details, please refer to FIGS. 1A-1B, 2-3, 4A-4B, 5-6, and 7A- Fig. 7D, Fig. 8, Fig. 9A-Fig. 9B, Fig. 10-Fig. 11 and related descriptions, which are not further described here.

Referring to FIG. 14, FIG. 14 is a schematic structural diagram of a rendering application server provided by the present application. The rendering application server in this embodiment includes: a receiving module 710 , a rendering module 720 and a sending module 730 .

The receiving module 710 is configured to receive the first viewing angle.

The rendering module 720 is configured to call the rendering engine according to the first viewing angle to search for the valid grid corresponding to the first viewing angle in the valid grid set, and generate a rendering according to the light intensity of the valid grid corresponding to the first viewing angle. The image, wherein the valid grid set is a set of valid grids corresponding to a preset viewing angle set, and the first viewing angle belongs to the viewing angle set.

The sending module 730 is configured to send the rendered image to the rendering application client.

For the sake of simplicity, the embodiment shown in FIG. 12 is not described in detail. For details, please refer to FIGS. 1A-1B, 2-3, 4A-4B, 5-6, and 7A- Fig. 7D, Fig. 8, Fig. 9A-Fig. 9B, Fig. 10-Fig. 11 and related descriptions, which are not further described here.

In the above-mentioned embodiments, it may be implemented in whole or in part by software, hardware, firmware or any combination thereof. When implemented in software, it can be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, all or part of the processes or functions described in the embodiments of the present application are generated. The computer may be a general purpose computer, special purpose computer, computer network, or other programmable device. The computer instructions may be stored in or transmitted from one computer-readable storage medium to another computer-readable storage medium, for example, the computer instructions may be downloaded from a website site, computer, server, or data center Transmission to another website site, computer, server, or data center by wire (eg, coaxial cable, optical fiber, digital subscriber line) or wireless (eg, infrared, wireless, microwave, etc.). The computer-readable storage medium may be any available medium that can be accessed by a computer or a data storage device such as a server, data center, etc. that includes an integration of one or more available media. The usable media may be magnetic media (eg, floppy disks, storage disks, magnetic tapes), optical media (eg, DVD), or semiconductor media (eg, Solid State Disk (SSD)), among others.

Claims (10)

1. A rendering method, characterized in that it is applied to a rendering application server of a rendering system, the rendering system further includes a rendering application client, the rendering application client is deployed on a terminal device, and the rendering application server is deployed on a remote rendering a node, the method includes:

   The rendering application server receives the first perspective;

   The rendering application server calls the rendering engine according to the first viewing angle to search for the valid grid corresponding to the first viewing angle in the valid grid set, and generates a rendered image according to the light intensity of the valid grid corresponding to the first viewing angle , wherein the valid grid set is a set of valid grids corresponding to a preset viewing angle set, and the first viewing angle belongs to the viewing angle set;

   The rendering application server sends the rendering image to the rendering application client.
2. The method according to claim 1, wherein the effective grid corresponding to the first viewing angle is specifically: a grid that can be observed from a viewpoint corresponding to the first viewing angle, wherein the grid is a pair of It is obtained by dividing the surface of the 3D model in the target scene.
3. The method according to claim 2, wherein the valid grid set is a set composed of valid grids corresponding to each view in the view set.
4. The method according to any one of claims 1 to 3, characterized in that:

   The perspective set is preset by the user on the rendering application server;

   The perspective set is obtained by the rendering application server according to historical perspective statistics of the rendering application;

   The perspective set is predicted and obtained by the rendering application server according to historical perspectives of the rendering application.
5. The method according to any one of claims 1 to 4, wherein the material of the effective grid comprises a diffuse reflection material and an optical material,

   In the case where the material of the effective mesh is a diffuse reflection material, the light intensity of the effective mesh includes the light intensity obtained by performing forward ray tracing on the effective mesh;

   In the case where the material of the effective grid is an optical material, the light intensity of the effective grid includes the light intensity obtained by reverse ray tracing from a specific angle that is the same as the angle of the first viewing angle.
6. A rendering application server, characterized in that the rendering application server comprises: a receiving module, a rendering module and a sending module;

   The receiving module is configured to receive the first perspective sent by the rendering application client;

   The rendering module is configured to call the rendering engine according to the first viewing angle to search for the valid grid corresponding to the first viewing angle in the valid grid set, and generate a rendered image according to the light intensity of the valid grid corresponding to the first viewing angle , wherein the valid grid set is a set of valid grids corresponding to a preset viewing angle set, and the first viewing angle belongs to the viewing angle set;

   The sending module is configured to send the rendered image to the rendering application client.
7. A rendering method, characterized in that it is applied to a rendering system, the rendering system includes a rendering application client and a rendering application server, the rendering application client is deployed on a terminal device, and the rendering application server is deployed in a remote rendering node, the method includes:

   The rendering application client sends the first perspective

   The rendering application server receives the first viewing angle; according to the first viewing angle, the rendering engine is called to search for the valid grid corresponding to the first viewing angle in the valid grid set, and the valid grid corresponding to the first viewing angle is based on the first viewing angle. generating a rendered image based on the light intensity of the grid; sending the rendered image; wherein, the valid grid set is a set of valid grids corresponding to a preset viewing angle set, and the first viewing angle belongs to the viewing angle set;

   The rendering application client receives the rendered image.
8. A rendering system, characterized in that it includes a rendering application server, a rendering application client, and a rendering engine, the rendering application client is deployed on a terminal device, and the rendering application server and the rendering engine are deployed on a remote rendering node ;

   The rendering application server is used to receive a first view angle; according to the first view angle, the rendering engine is called to search for the valid grid corresponding to the first view angle in the valid grid set, and the valid grid corresponding to the first view angle is called according to the first view angle. generating a rendered image based on the light intensity of the grid; sending the rendered image; wherein, the valid grid set is a set of valid grids corresponding to a preset viewing angle set, and the first viewing angle belongs to the viewing angle set;

   The rendering application client is configured to send the first viewing angle and receive the rendered image.
9. A computing node, characterized in that, the computing node includes a processor and a memory, and the processor executes a program in the memory, thereby executing the method according to any one of claims 1 to 5.
10. A computer-readable storage medium, characterized by comprising instructions, which when executed on a computing node, cause the computing node to execute the method according to any one of claims 1 to 5.

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