Does SDL_DisplayFormatAlpha() not work for you?
-bill!
I haven’t got around to try it yet (I have all the stuff wrapped in my OO
engine) but one defenite improvement was converting all 24-bit images to
32-bit imaes with ->format>Amask set to zero. This presumably allows the
hw/sw blitter to execute faster as it does not need to deal with 3-btye
alignments for every pixel (my theory at least).
My next plan is to have a 3rd software buffer to use as a temporary
destination before sending to the hardware buffers for flipping. I’m
basically counting on software rendering as I have implemented some custom
blitting like rippled blits, al-alpha-channel based background displacement,
blurred blits etc. If this isn’t enough I’ll consider dirty rectangle /
dirty zone blitting next.