glFramebufferTexture2D performance

Question

I'm doing heavy computation using the GPU, which involves a lot of render-to-texture operations. It's an iterative computation, so there's a lot of rendering to a texture, then rendering that texture to another texture, then rendering the second texture back to the first texture and so on, passing the texture through a shader each time.

My question is: is it better to have a separate FBO for each texture I want to render into, or should I rather have one FBO and bind the target texture using glFramebufferTexture2D each time I want to change render target?

My platform is OpenGL ES 2.0 on the iPhone.

score 6 · Accepted Answer · answered Jun 19 '10 at 02:28

6

On the iPhone implementation, it is inexpensive to change the attachment, assuming the old and new textures are the same dimensions/format/etc. Otherwise, the driver has to do some additional work to reconfigure the framebuffer.

answered Jun 19 '10 at 02:28

Frogblast

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score 3 · Answer 2 · answered Jun 14 '10 at 11:43

3

AFAIK, better performance is achieved by using only one FBO, and changing the texture attachments as necessary.

answered Jun 14 '10 at 11:43

Dr. Snoopy

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Do you have any resources that support this? – nornagon Jun 14 '10 at 15:00
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http://http.download.nvidia.com/developer/presentations/2005/GDC/OpenGL_Day/OpenGL_FrameBuffer_Object.pdf Slide 28 onwards. – Dr. Snoopy Jun 14 '10 at 15:37

score 0 · Answer 3 · answered Nov 28 '16 at 07:18

0

The best way is to do benchmark.

answered Nov 28 '16 at 07:18

andrewchan2022

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glFramebufferTexture2D performance

3 Answers3