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Old 31 May 2020, 21:39   #22
VladR
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Join Date: Dec 2019
Location: North Dakota
Posts: 217
Quote:
Originally Posted by chb View Post
For a span filler and solid polygons the blitter is in clearing mode (D only)*, so the idle cycles become relevant, meaning the CPU can work at full speed in parallel to the blitter here if no other DMA is active. That might be useful for large spans - but probably the overhead to setup the blitter makes it still slower than a CPU-only routine.

* apart from the first and last word
Yeah, I reckon for something like spaceships (say, in a game like Guardian), it would be faster to use a CPU-only codepath as most of the time, the spans would be just 2-8 pixels.


Large polygons - like a floor, or a road, would use a blitter codepath and would in parallel let CPU compute endpoints of next span.


Just not fullscreen on 7 MHz at 60 fps...
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