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4.1.1 Pixel Ownership Test


The first test is to determine if the pixel at location in the framebuffer is currently owned by the GL (more precisely, by this GL context). If it is not, the window system decides the fate the incoming fragment. Possible results are that the fragment is discarded or that some subset of the subsequent per-fragment operations are applied to the fragment. This test allows the window system to control the GL's behavior, for instance, when a GL window is obscured.

David Blythe
Sat Mar 29 02:23:21 PST 1997