PDA

View Full Version : pixel ownership and the backbuffer



ExWired
03-20-2001, 10:21 PM
Relevant to FAQ topic 14.070 - If I render to the backbuffer, are pixel ownership tests still performed? Or is that a implementation dependant detail?

Relic
03-20-2001, 10:46 PM
The SPEC and the FAQ are very clear about that. Pixel data in unexposed window areas is not defined.
Imagine the per pixel informations as a big bitfield. Ownership test is over all buffers then.

Serge K
03-23-2001, 08:11 PM
Originally posted by ExWired:
If I render to the backbuffer, are pixel ownership tests still performed? Or is that a implementation dependant detail?
This test is always performed by 3D cards with shared backbuffer.
Most of the consumer-level 3D cards uses separate backbuffer for each rendering context. In this case ownership test is ignored.

Relic
03-26-2001, 01:53 AM
>>Most of the consumer-level 3D cards uses separate backbuffer for each rendering context. In this case ownership test is ignored.

But that doesn't help, because you'll never know.
E.g. lets say rendering to the backbuffer does not do pixel ownership. What about glReadPixels, glCopyPixels, glCopyTexture etc.

The only valid assumption is, that it's undefined.