GlFramebufferTexture2D Performance

Question

I am doing heavy calculations using a GPU, which includes many rendering texture operations. This is an iterative calculation, so there is a lot of rendering the texture, then rendering that texture to another texture, and then rendering the second texture back to the first texture, etc., Passing the texture through the shader every time.

My question is: is it better to have a separate FBO for each texture I want to display, or do I need to have one FBO and bind the target texture with glFramebufferTexture2Devery time I want to change the rendering target?

My platform is OpenGL ES 2.0 on the iPhone.

Answer 1

In the iPhone implementation, it is inexpensive to change the attachment, assuming that the old and new textures have the same size / format / etc. Otherwise, the driver must do additional work to reconfigure the framebuffer.

Answer 2

AFAIK, the best performance is achieved by using only one FBO and changing texture embeddings if necessary.

Answer 3

The best way is to do a quiz.