Hello, I'm studying modern OpenGL for a project (I always used ancient immediate mode when I needed it) and one of my task is to manage some particle emitters.

I discovered about Transform Feedback and the process seems quite clear but I have two doubts to specific questions: can I attach a geometry shader AFTER the transform feedback phase (and just when rasterizing). I ask this because it seemed efficient to have points which are moved and managed by the TF, these points then become quads thanks to a shader so that I can apply a texture to them. I know about point sprites but they seem some what limited so I would like to avoid them.

The second question is related to using the transform feedback with a vertex array object: is there any limitation or drawback in using a VAO in this context?

Thanks in advance!

Note: forgot to mention, since I'm currently working on OS X my target is core 3.2 until 10.9 ships