Accum buffer. Rendering is dead slow?

Why rendering via accum buffer is so slow? Does it depends on video card you possess? I have Radeon9200SE and it runs pretty fast in double-buff, 24bit, RGBA OpenGL mode. But when Im trying using motion blur etc. via accum buffer, rendering speed falls down as thou you dont have accelerator at all (I render just a couple of cubes etc. ‘Red Book 1.1 accanti.c’ sample like code)

Originally posted by 9ine:
Does it depends on video card you possess?
Yes! You need at least a Radeon 9500++ or a GeforceFX for that.

I have a ATi Radeon 9600XT (GeCube GC-R96XT-C3 Encore Edition), and i have NO accumulation buffer… :eek:

Can anyone explain that?

I somehow doubt that you have NO accumulation buffer , a software only accum buffer perhaps :wink:

What os and drivers are you using?


I use WinXP with SP1 and Catalysts 4.7.
And i’m quite sure, there isn’t one, because I tried to do some kind of antialiasing (i know there are better methods), and it didn’t work (but it worked on the old geforce 2, but at less then 1 fps), and i checked the accum color bits and they are all 0 and i checked with glinfo(from and it said zero accum buffers.

Anyhow… I then did it with something that worked faster then i expected. I created a texture at startup and then drew the current frame, and used glCopyTexSubImage2D to save the current frame, and then drew it 4 times in different positions.
it works at about 50 fps and 5-15 on the old one.

But i think there is some kind of a bug in ATis drivers… i have a 64x64 texture and it comes out black(when i use this AA, without it it draws normally), while it comes out normal on the nvidia geforce 2. Maybe ill post a screenshot when i come home.