Performance of GL_ARB_depth_texture on Radeon 9700

OpenGL OpenGL: Advanced Coding
1

Hello,

I’m copying the depth buffer to a texture using glCopyTexImage*, and GL_ARB_depth_texture, GL_ARB_shadow extensions on a Radeon 9700 Pro card.

However, my very simple app runs at 6fps! What is the expected performance of using these extensions on this video card?

The system is a P4 2.4 GHz, with 1GB memory.

Thanks.

2

Turn off FSAA. I’ve had the same problem and reported it to ATI dev relations. They responded, but didn’t give any explanation.

3

I have discovered the same “problem” in my own shadowmap-demo some time ago (also posted it here).It runs awfully slow when turning on FSAA if you use simple Render-To-Texture.
Change your application to use PBuffers instead of simple Render-To-Texture, and you should get better performance.

4

Thanks for the advice.

Just so people know, using Catylyst 3.2 in display properties, I set the Anti-Aliasing to ‘Application Preference’ (which for my application disables FSAA), and now get 900fps.

Before, it was set at 4xAA.

Thanks again for the help.

5

Just to let you know : ‘Application Preference’ means that AA is turned off.

6

Sorry for digging this topic up, but as it seems, ATI have fixed this problem with their latest Catalyst 3.7!
I just tested it with my own shadowmap-demo, that now runs with active 4xAA at about 80fps, whereas the same AA-setting under Catalyst 3.6 would cause it to crawl down to about 3-4fps!

7

Originally posted by PanzerSchreck:
Sorry for digging this topic up, but as it seems, ATI have fixed this problem with their latest Catalyst 3.7!
I just tested it with my own shadowmap-demo, that now runs with active 4xAA at about 80fps, whereas the same AA-setting under Catalyst 3.6 would cause it to crawl down to about 3-4fps!
This may be the same “UT2k3 character shadows with AA” thing that has been mentioned in the 3.7 release notes

8

Originally posted by zeckensack:
This may be the same “UT2k3 character shadows with AA” thing that has been mentioned in the 3.7 release notes

Those shadows didn’t appear to use depth textures, though. . . Perhaps the real issue was with slow framebuffer reads. . .