Really slow texture app

OpenGL OpenGL: Basic Coding
1

I am running a Geforce MX on NT4. My scene is has 244 quads each textured with a different 66x66 RGBA texture. The problem is the frame rate is about 1/2 second per frame. (No NTSC around here.) What can I do to speed things up?

I have used glBindTexture to associate each bitmap with a name.
All textures are have been loaded into residency status using
glTexParameter(GL_TEXTURE_2D,GL_TEXTURE_PRIORITY,1.0) during binding.
I have omitted PFD_GENERIC_ACCELERATED and PFD_GENERIC_FORMAT from PIXELDESCRIPTORFORMAT.dwFlags so the ICD is used.
I have implemented back-face culling so roughly half the quads are dumped.
I have also implemented some crude frustum polygon culling so more quads are dumped.

I have one light activated and most textures are subject to glAlphaFunc. Each frame is about 600x600 pixels.

After culling my code only sends about 35-60 quads to OpenGL to be rendered. That means only 1MB of textures out of a total of 4MB is actually used at any given time. I don’t think that sounds too extreme considering my card has 32MB RAM.

Any suggestions?

2

Because you say you are using a 66x66 texture, I am assuming that you are using texture borders.

Under some conditions, texture borders will force a GeForce to use software rendering, which would probably explain the low frame rate.

As an alternative to texture borders, you might try using 64x64 textures with the GL_CLAMP_TO_EDGE_EXT texture wrap mode.

j

3

You’re right! Using 64x64 textures the app ran incredibly fast. So what’s up with bordered textures anyways?

To show my appreciation I will name my next Diablo II character after you. Barbarian j

4

I don’t know what exactly bordered textures mess up, just that under some conditions, they force software rendering.

There’s a FAQ on the nVidia website that talks about how to get the most performance out of their graphics cards, as well as things to avoid doing. It’s at http://www.nvidia.com/Marketing/Developer/DevRel.nsf/FAQ_Frame?OpenPage

Barbarian j…

I like the sound of that.

j