Z-Buffers on Radeon 8500

OpenGL OpenGL: Advanced Coding
1

I know this is very specific to that card and this usage, but I would like to know if I can explicitly create a depth pbuffer (using WGL) rather than having to request a colour buffer as well?

Thanks for any help.

2

There’s no mechanism in OpenGL that allows you to do this on a Radeon 8500 or any other card. Z-Buffers (as with the color buffer and stencil buffer) are attached to the pixel format.

D3D has this capability. Hopefully OpenGL 2.0 will have it, but right now it isn’t possible.

3

Thanks for this info. It was probably expecting a bit much anyway to cast a 32-bit Z-buffer to a color bitmap I could use as a shadow depth texture. I’ll have to have a rethink…

4

We support pbuffer pixel formats without color buffers. These are primarily useful for rendering to and then copying to a shadow map (lets you use a shadow map larger than your window), but they can be used for other things as well.

  • Matt