The Research And Implementation Of Real-time Shadow Algorithms In Virtual Scene

As key technology of real-time rendering, shading can add realism to the virtual scene, so this technology is widely used in 3D games, animating Movie & TV, 3D GIS systems and computer aided design and manufacture. Shadows are important to computer graphics because they add realism and help the viewer identify spatial relationship. Shadows are also crucial for the human perception of the 3D world.The techniques of rendering real-time soft shadow consist of three main parts. The first part is a short introduction for some technique about light, for example lightmap, antialiasing and fuzzy. They have an important aspect to improve the quality of shadow. We can use lightmap to simulate real illumination effect and use antialiasing to make sawtooth shadow edges straight. The second part we introduce some real-time shadow rendering algorithms and they are the basis of generating soft shadow. In this time ray tracing, shadow maps and shadow volumes are described in details. Shadow maps are computed in image space, rendering shadow with depth maps' information in scenes. Comparison to shadow maps, instead of computing in image space, shadow volumes generate shadows based on object geometry information in object space. It consider mainly light and objects intersection in ray tracing and how to reduce the potential number of intersections become a future subject.Image space algorithm and object space algorithm are become two branches of soft shadow rendering. The character of image space algorithm is ensuring real-time rendering but having the poor-quality performance, while object space algorithm brings high-quality image but low frame rates.Combining these algorithms allows for rapid previewing followed by efficient high-quality rendering. we present a real-time soft shadow algorithm which based on the shadow maps. Experiments demonstrate that the algorithm can provide visually pleasing effect for the complex objects and achieve satisfying frame rate at the same time. So we offer an effective way to generate real-time soft shadow for the complex scenes.