render texture..

OpenGL OpenGL: Advanced Coding
1

I got terrible framerates when i try render_texture on an nvidia card… much worse than render to a pbuffer and copy to a texture, like on a 1024*1024 texture i got 2fps for render_texture, and >50 for a copy to texture on the same scene… am i doning anything wrong or is the drivers not optimized yet? (gf3, 28.32 drivers, RGBA texture)

/Mikael

2

I have made a slightly upset post about the same thing.

I really want some answers on this. I want to say it is really a big driver issue but I really don’t see how. I could get a 3 or 4 fold increase in framerate by using glCopySubImage2d instead of binding the pBuffer using render_to_texture. Even the nvidia simple render to texture exhibits the exact same fps increases so I am quite sure it is not something I am doing in my code.

I really don’t know what to tell ya. It is pissing me off too.

Devulon

3

Don’t say that, they’ll only make glCopySubImage2d() slower…

4

I’ve discussed this with NVidia a few weeks ago. I sent them my test app, and they agreed that it was a driver problem. If it’s of any use to you, the slowdowns only seem to occur if you glClear() the pbuffer every frame.

Fortunately, the problem has since been fixed, and I’ve been told that the next driver release should perform as expected, i.e. WGL_ARB_render_texture is faster than glCopyTexSubImage2D()…

– Tom

5

Anyone has a code(or fragment) that builds/update
a mipmap from framebuffer using glCopyTexImage2D / glCopyTexSubImage2D?

I can’t set mipmap levels using glCopyTexImage2d. Level 0 is currupted as
I set the other mipmap levels. Don’t know
if it is a nvidia driver problem or not.

I really need some help.I’m stuck with this problem for more than 1 1/2 week.

Thank you all for any help.

6

The SGIS_generate_mipmap extension?

7

your not alone. I’ve been trying to figure out the same problem. I set up a 1024x1024 pbuffer for refraction, glCopyTexSubImage2D() runs at 70fps, binding the pbuffer using the render_texture extension yields 12fps.

I am calling glClear(GL_DEPTH_BUFFER_BIT) in the pbuffer, but i dont think that that is the source of the slowdown