大规模虚拟环境中实时阴影生成技术

为了解决大规模场景中阴影生成的真实性和实时性问题，通过平均分割和对数分割相结合的方法，利用平行于视觉投影面的分割面将视截体划分成不同的深度部分；然后对每个分割部分生成对应的阴影图；最后利用多个阴影图代替单个阴影图进行渲染。这种方法既减少了运行时的缓冲空间，又提高了阴影质量，尤其适合于动态大规模环境中实时阴影的生成。用VS2005和OpenSceneGraph实现了算法的绘制，达到满意的视觉效果和生成速度。

Real-time shadow rendering technology for large-scale virtual environments

In order to solve the problem of reality and real-time performance in the shadow generation of large-scale scene, the view frustum was divided into different depth ranges by using split planes parallel to the view plane, with combining uniform split scheme and logarithmic split scheme; then the paper proposed to generate multiple smaller shadow maps for these split parts; at last the scene was rendered with multiple shadow maps with smaller sizes instead of a large size one. This algorithm can produce real-time shadowing effects with less texture memory, but significant improvement of shadow qualities, especially for the dynamic and large-scale virtual environments. The algorithm was implemented in VS2005 and OpenSceneGraph, and it can satisfy the requirement of quality and real-time performance.