View Full Version : hidden window crouching acceleration

06-07-2004, 06:25 AM
Do you happen to know whether there is any guarantee of hardware acceleration for OpenGL contexts which have been created using the hdc of a hidden window?

Also, if you are rendering to a window which is not hidden, and then hide it, will the hardware acceleration continue to work?

06-07-2004, 09:12 AM
As a general rule there is no guarantee at all for hardware acceleration. Once you have a rendering context from a proper implementation (ie from your card's vendor, not the generic MS software 'thing'), you can very well fall on a software path, depending on the features you use (the imaging subset comes to mind).

Regarding the particular case of a hidden window, the problem is more that its framebuffer content is undefined. For (safe) offscreen rendering, you have to use pbuffers.

06-07-2004, 10:41 AM
The problem I am having is that I would like to write a library of functions which use OpenGL to perform different calculations. The only features that I am using so far are below the 1.1 spec. In order to have such a library which must work in any program unbtrousively, even if the program itself does not use OpenGL at all I am forced to create a hidden window, initialize OpenGL's context to use it as a source and then perform whatever rendering is necessary using that context.

Do you know of any other way of handling this problem? (Writing a library that does computations using OpenGL with hardware acceleration while not creating a visible window)

06-07-2004, 02:43 PM
Pbuffers. Or software acceleration :)

06-10-2004, 04:44 AM
Except that PBuffers require windows. You cannot get to the WGL extensions without first creating a windowed accelerated GL context. PBuffers won't help.