Clip dirty rects to surface rects in surface coordinate space.
Dispatch vertices in surface coordinates and let the graphics hardware
handle the transformations. Clipping in global coordinate space
implies a useless roundtrip on the CPU to get the clipped polygons
back in surface coordinates for the buffer transformation. Clipping in
surface coordinate space prevents that.
This might seem counter-intuitive at first because in surface space
it's the dirty rects that are clipped to axis-aligned surface rects,
while it's the opposite in global space.
The projection matrix now combines the view and the output transforms.
Signed-off-by: Loïc Molinari <loic.molinari@gmail.com>
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