[Note: I discovered this bug while testing with the i965 driver, but
it's certainly possible that it's actually a general bug in mesa.]
The OpenGL specification indicates that the glBitmap operation should
generate fragments. It says:
Bitmaps are rectangles of zeros and ones specifying a
particular pattern of fragments to be produced. [OpenGL 3.0 §
I recently added the occlusion_query_meta_fragments test to piglit to
ensure this behavior. It executes a glBitmap operation within an
occlusion query, expecting a result of the same number as pixels as
set in the bitmap.
This test currently fails, (the occlusion query reports 0 fragments
rather than the expected 8 fragments for a 4x4 bitmap with 8 of the 16
Author: Eric Anholt <email@example.com>
Date: Tue May 21 16:20:18 2013 -0700
intel: Count fragments in our blitter-based glBitmap() path.
Reviewed-by: Ian Romanick <firstname.lastname@example.org>
Reviewed-by: Kenneth Graunke <email@example.com>
on Jan 24, 2017 at 09:02:53.
(provided by the Example extension).