GL_KTX_buffer_region what is it?

not sure if this post should go in the beginners forum…

but my graphics card (ATI Radeon) supports this opengl extension, but I can’t find any information about it…

what is it?

what does it do???


Pseudo specs are here: Buffer Region Extension

Use a better search engine

[This message has been edited by Relic (edited 03-02-2001).]

You should read WGL_ARB_buffer_region at the extension registry. This extension has a real spec and is ARB approved. It is intended to legitimize the old KTX extension.

Essentially, it allows the application to do a “save this region” and “restore this region” of a depth or color buffer (stencil, too, I think) in a very optimized way. You could do the same thing with readpixels/drawpixels, but that’s pretty much the worst case for performance.

I think the Radeon only supports the Kinetix extension not the ARB one.

WGL_ARB_buffer_region as well as GL_KTX_buffer_region can save stencil regions.

I’ve got a question for you Cass (or Matt). Will the GF3 support the WGL_ARB_pbuffer extension, and can’t a pbuffer be used roughly for the same purpose as an auxiliary buffer (the question could be what’s the purpose of pbuffers)?

Our next driver release will support pbuffers on all chip architectures – TNT, GeForce, and GF3.

We have a lot of interesting plans for things we can do with pbuffers.

Pbuffers and aux buffers each have their own advantages and disadvantages. Most notably:

  • your aux buffers are always the same size as your window (convenient if you want that; a problem if you want a temp buffer larger or smaller than your window)
  • aux buffers also are always the same color depth, and if you are using multisample, are bound to the same multisample buffer as your window
  • aux buffers share your window’s depth buffer, while pbuffers can have their own
  • a pbuffer doesn’t have to have a color buffer; you can have a depth-buffer-only pbuffer

They’re different mechanisms and are used for different things.

[Hmm, maybe I should go ahead and implement those aux buffers…]

  • Matt