Research Of Shadow Algorithm In 3D Graphics Engine

Nowadays, with rapid development of computer hardware and computer graphics,3D graphics engine as a branch of computer graphics applications, in today's computer applications, plays an important role in the 3D computer display, such as virtual reality Technology, military simulation, to experience the product display,3D games, and so on. The shadows in 3D graphics engine, realistic simulations, as reflected an important indicator of the degree, has been researchen on abroad for quite a long time, but in our country, the research in this area is still relatively poor.As we known, the embodiment of the shadow of occlusion relationships between objects and objects which plays a very important role in the important information displayed in the 3D realism. The shadow algorithms that more popular today, most of the existence of many problems, such as real-time rendering, which is a very good sense of interaction with the user, and some are too dependent on the outline of objects, more demanding requirements of such objects and so on. Based on programmable graphics card, this paper studies the major shadow algorithms in graphic engine, which include their strengths and weaknesses of the detailed analysis, Base on the strengths and weaknesses, We put forward a new shadow algorithm which use the programming of graphics cards The algorithm is based on pseudo-soft shadows shadow map algorithm, the shadow mapping algorithm itself exist some problems, such as the same width of the half shadow, and penumbra width consistent aliasing and other problems, so this algorithm in the following special aspects:First:Design and implement a new algorithm, from start to improve the accuracy of the shadow map to enhance the graphics realism; the second:the introduction of the PCF algorithm and woo the average depth value of the principles of thinking to solve the umbra of the aliasing problem; Third: This article uses a single light source sampling methods to improve the efficiency of shaded rendering, while the algorithm is based on programmable graphics card, and improve the efficiency of the algorithm.In the algorithm, this paper from the shadows to render quality and frame rate two standard starting the experiment proved that the improved algorithm as much from the rendering model to observe the shadow rendering frame rate and display quality, than the shadow map algorithm (shadow map), the shadow of the body algorithm (shadow volume) and the variance shadow maps have a certain increase.Finally, as this algorithm uses OpenGL graphics API, and use language as a shading language GLSL hardware accelerated computation of the programme, and eventually implement this algorithm.