Real-time Dynamic Soft Shadow Technology Research And Applications

Shaodow is a piece of dark areas which is created by the opaque object blocks the light. Shaodw as the projection of object which is created by light in real life has become an indispensable part to enhance the computer garphics's rendering realism. The boundary section of shadow can help people understand the shape of objects, as well as the relative position of objects. Therefore, there is more and more study about real-time dynamic soft shadows at home and abroad. The main algorithm of shadow is shadow mappping and shadow volumes algorithm, for the expensive spending of shadow volume algorithm, the most popular algorithms is shadow mapping algorithm.In this dissertation, the study of real-time dynamic soft shadows can be divided into the following three aspects:First of all, a variety of algorithms of real-time dynamic soft shadows are researched: 1. The shadow mapping algorithm is analysied, shadow mapping algorithm is a kind of shadow generation technology base on image space.Its basic principle is do two rendering to get the shaodw. 2. The perspective shadow mapping algorithm is analysied, this algorithm generate the shadow mapping through perspective space, and provide high-resolution for near object when provide low-resolution for object which is far away the viewport. This algorithm solves the perblom of aliasing. 3. The light space perspective shadow mapping is described, this algorithm merges the shadow mapping algorithm and the perspective shadow mapping algorithm.Secondly, the algorithm of layed percentage-closer fliter which is based on the parallel split shadow mapping is proposed. First, the parallel-split shadow mapping algorithm is detailly analysied, then the percentage-closer filtering algorithm is introduced. Finally, combine the parallel-split shadow mapping algorithm with percentage-closer filtering algorithm, layed PCF based on PSSM is proposed. And two kinds of selection method of kernel size with depth map in the algorithm of layed percentage-closer fliter which is based on the parallel split shadow mapping are proposed: user select and geometric progressive based on the penumbra. Layered PCF algorithm based on PSSM can also simulate real-time soft shadows, it can render the shadow of more complex geometry while ensuring the quality and satisfying the efficiency for real-time rendering, prividing an effective solution to generate real-time shadow in virtual environment.Finally, the real-time dynamic soft shadow effect is applied to the actual scene editor. First, the function modules of the RomansStudio Scene Editor are introduced. Second, the shaodw module and the key class of the real-time dynamic soft shadow are introduced, analysed and implemented. Then the module design and application of the real-time dynamic soft shadow in the scene editor are analysed. Finally, the real-time dynamic soft shadow effect is applied to the scene editor and the result is analysed.