D3D实现的雾效，效果很酷，很有参考价值

The Volume Fog sample shows the per-pixel density volumetric rendering technique. The fog volume is modeled as a polygonal mesh, and the density of the fog at every pixel is computed by subtracting the front side of the fog volume from the

在opengl中用c++实现的体积纹理渲染-In opengl texture with c++ achieve volume rendering