Cone Tracking Algorithm And Adaptive Light-cut Sampling Algorithm Based On Chessboard Rendering

Global illumination has been a difficult and hot research field of graphics and games,but also because of the difficulty associated technological breakthroughs of the larger,higher value so that it has been a hot topic in the field of computer graphics and 3D games.Reality and real-time are the two major goals pursued by rendering technology,and it is difficult to have both.Different algorithms often achieve the best balance between the two according to the rendering scene and the focus of the target.This article mainly focuses on the real-time global illumination algorithm based on voxel-based cone tracing technology and the many-lights rendering algorithm based on light cut.The main research work includes the following three parts:1.There is a dynamic real-time global illumination algorithm based on the voxel-based cone tracing algorithm.It is very common to use local lighting in real-time rendering,The surface points of the object are only calculated when they are visible.Global illumination calculations use information from other objects,and this is the most difficult point to simulate.Therefore,in real-time rendering will be willing to sacrifice some quality for efficiency and accuracy,the most common way is to simplify and precomputed.The algorithm can quickly render and achieve better results in complex environments through pre-filtered geometric representations and friendly GPU data structures.2.An improvement to the voxel-based cone tracing algorithm is proposed.On the basis of the algorithm mentioned in the first part,an improved measure combining checkerboard rendering is proposed for time efficiency.Through the sampling mode at quarter resolution which reduces the rendering time by restoring the original resolution image with the least loss of visual quality.3.An adaptive light-cut sampling global illumination algorithm is proposed.The difficulty of many-lights rendering is that there are too many light sources in the scene,and it is impossible to naively calculate the contribution of each light source to the shading point.Traditional light sampling will sample the light source contributed by the lack of light under the line of sight.The sampling based on the bidirectional reflectance distribution function will generate a lot of noise due to insufficient sampling,the general light-based sampling algorithm does not work well on glossy objects.This paper approximates the projection of the enclosing sphere of the light node on the hemisphere of the shading point as the projection of a polygon,plus the calculation of the angle which gives a new algorithm for selecting the light node,and combines traditional sampling algorithms to implement an adaptive algorithm.The effect of this algorithm on glossy objects is better than that of traditional methods,and it is also acceptable in terms of time,achieving a balance between efficiency and quality.