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View Full Version : overlay a semi-transparent window on an OpenGL window



Coconut
02-13-2002, 12:29 PM
We are working on an application which has floating windows.
Since Windows 2000 supports semi-transparent windows, we are thinking to have windows floating on top of the main OpenGL window.
It works fine with the generic implemention but has some crappy flickering when running with hardware OpenGL.
Is it a driver's issue? I have a GeForce2 card.

jmathies
02-15-2002, 10:35 AM
Drivers tend to punch a hole through the desktop vs. the generic renderer which uses GDI. I think your going to have some problems getting this to work reliably in all cases.

dorbie
02-17-2002, 06:01 AM
Considering there's no mux and no blended mux, the flicker is probably the overlay getting rendered & blended against the frontbuffer.

In windowed rendering swap copies the image to the display buffer, boom, you're overlay is gone, presumably this then triggers some king of blend of the overlay with the display buffer.

Unless you have more support in hardware this kind of problem it's almost inevitable.