把你们的力量联合起来！
先搬运下Projective Texture Mapping的简介[from wiki: http://en.wikipedia.org/wiki/Projective_texture_mapping]：
Projective texture mapping is a method of texture mapping that allows a textured image to be projected onto a scene as if by a slide projector. Projective texture mapping is useful in a variety of lighting techniques and it is the starting point for shadow mapping.
Projective texture mapping is essentially a special matrix transformation which is performed per-vertex and then linearly interpolated as standard texture mapping.
PTM既指生成纹理坐标给顶点的过程，也指在光栅化过程中的纹理坐标的计算。[background: 1.OpenGL Pipeline 2.纹理坐标生成全过程]。笼统地，可认为是由texture image到primitive的计算过程。
Rasterization Details:
最简单的使用纹理的过程是: [to add].
【待续…】