diffuse + specular lighting shader for xna4

Silverlight 5的3D引擎开源项目,基于Silverlight 5平台。 支持以下功能： Collisions Diffuse channel Ambient channel Textures (including light maps) Per-pixel per-vertex shader Models/cameras and lights 项目开源，可自行修改！-Silverlight 5 3D engine open source project, based on Sil