是否可以使用纹理坐标/矩阵与OpenGL点精灵？

I'm working on a particle system and point sprites would be nice to use. Unfortunately I have a constraint that I pack ALL my textures in a single texture atlas. This is a huge overall speed boost to my engine as I never have to switch texture bindings. But as a result I need to be able to specify a source texture rectangle for my particles. I'm working on a particle system and point spri