| [AD] OpenGL and upside down |
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If you lock the OpenGL back-buffer, it currently reads the pixels and
then reverses the order of the rows (because OpenGL bitmaps start from
the bottom up and Allegro start from the top down). When you unlock,
the opposite process occurs. This reversing is done by a load of
memcpy-ing.
Would it be possible to avoid this by returning a locked region with
data pointing to the last row of the region but with a negative pitch?
Pete