I'm using FBO to render to several textures. Now I need to readback some states of rendering buffer(FBO textures) to host memory (PC RAM) when I'm rendering. I have read some brief from nvidia (Fast Texture Downloads and Readbacks using Pixel Buffer Object in OpenGL) how to use Pixel Buffers to faster read out the frame buffer and download data to texture.
My question is, if it is usefull use FBO and PBO TOGETHER to download and readback textures data. And what is better to use glGetTexImage or glReadPixels to read out FBO texture?