Research And Application Of Key Technology In CUDA-Based Real-Time Shadow

Rendering of shadow plays an important role in enhancing realism of virtual scene. However, it generally requires a lot of calculation and consumes. With the development of the ability of GPU, it becomes an important research direction to use GPU for graphics acceleration. As a parallel computing hardware and software architecture of GPU, CUDA allows developers to access GPU hardware design on API level. Therefore, based on this situation, our thesis mainly researches on how to use CUDA to accelerate shadow rendering.Image-Based and Geometry-Based are two main methods of shadow rendering. Image-Based method can generate shadows quickly and it is independent of scene complexity, but it has the disadvantages of aliasing and low quality. Instead, Geometry-Based method analyzes the scene complexity, thus can generate high quality shadow, but need more resources. Compared with these two methods, our thesis researches on and tests image-based PCSS algorithm and geometry-based silhouette edge algorithm respectively.To begin with, this thesis discusses how to accelerate rendering shadow in PCSS algorithms based on CUDA parallel architecture. In this algorithm, it uses parallel computing for higher transmission frequency of vertex data, then passes these data directly to GPU rendering pipeline to avoid the computation process in the CPU.Furthermore, this thesis investigates the silhouette edge algorithm in rendering shadow volume. At first, the thesis compares two CPU-calculating modes to generate silhouette data, and then probes into and experiments on how to generate silhouette by using GPU geometry shader. At last, we improves the procedure of CPU generating silhouette date, using CUDA to attain the accelerate of silhouette computing.Finally, in order to use this technology in our project, the thesis investigates how to integrate CUDA framework with Ogre rendering engine, then using CUDA to render real-time shadow effectively.In a word, based on CUDA parallel computing architecture,this thesis researches on and implements real-time shadow rendering algorithm, and achieves the goal of improving the performance in dynamic scene and silhouette edges shadow rendering.