View Full Version : Rendering to buffer for off-line storage

03-05-2007, 08:30 AM

In my application, at some point I'd like to use OpenGL to fill a framebuffer that I want to have saved. Performances doesn't matter, but I need to ensure that my scene is rendered properly and not overlapped by some other operating system window.

glReadPixels() on my regular GL context doesn't seems to ensure that, eg: on a command-line version of my tool, I often get windows garbage over my buffer. What I'd like to do eventually is to render directly into RAM.

Are PBuffer the solution?
Anything easier?
It is possible via Windows/WGL (sorry this isn't stricly a GL question, then) to create a DC that doesn't map to the screen but to RAM?

I'm running Windows XP, Radeon 9800 if that matter.


03-05-2007, 09:06 AM

PBuffer could be used but they are obsolete and replaced by the FBO extension.
Check Google for off-screen rendering.


03-05-2007, 10:34 AM
As Ido said, use the GL_EXT_framebuffer_object extension (just in case you didn't know what FBO is). The specification in the registry has a small usage example at the end that is usually enough to get started.

03-06-2007, 12:44 AM
Thanks for your answers.
How's the hardware/driver support for FBO?
Since when are those decently supported by hardware and/or drivers?
Want to make sure that 2-3 y/o hardware won't get stuck due to FBO usage.