mipmapping with FBO's
Author
Has anyone here seen a huge slow down in FPS when using glGenerateMipmapEXT? I am not happy with the fps drop when I use mipmaps with my FBO's. Anyone else seen this behavior? and if not what are you doing that I am not! :) Thanks
I'm not sure what I'm doing that you're not doing, but I've never seen this behavior. In fact, my code speeds up when I use glGenerateMipmapEXT (as it should, because mipmapped textures fit into cache better). If I could gander a guess, I'd say you might not be using a square power of two framebuffer.
Author
void FBO::ShutdownBuffer(void){ glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, 0); if(mipmapping) { for(unsigned int x = 0; x < numColorTextures; x++) { glBindTexture(texture_target, colortextures[x]); glGenerateMipmapEXT(texture_target); } glBindTexture(texture_target, depthtexture); glGenerateMipmapEXT(texture_target); }}thats the rendering code... and the sizes are 1024x1024
u should see a slowdown, so how much of a slowdown (5-20% i expect is normal) how much are u seeing? is it major eg ~10x if so post your texture type
Author
well I drop from 40-45 to 0-4 fps...
settings
if I use GL_LINEAR_MIPMAP_LINEAR or GL_NEAREST_MIPMAP_LINEAR no difference.
GL_LINEAR is GL_TEXTURE_MAG_FILTER. So I am unsure what is going on.
settings
if I use GL_LINEAR_MIPMAP_LINEAR or GL_NEAREST_MIPMAP_LINEAR no difference.
GL_LINEAR is GL_TEXTURE_MAG_FILTER. So I am unsure what is going on.
Sounds like a drop to software. Are you sure your card supports the extension? It might be software emulated for some bizarre reason..
Quote:Original post by MARS_999
well I drop from 40-45 to 0-4 fps...
ok, thats a hell of a hit...
How about trying it sans mipmaps first, then add colour mipmap generation back, one at a time, then remove and do depth only and finally put them all back and see where your fps bombs out.
This topic is closed to new replies.
Advertisement
Popular Topics
Advertisement
