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Demos Amiga Demoscene Archive Forum / Coding / Polygon filling - CPU vs. Blitter

 

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jar
Member
#1 - Posted: 30 Oct 2008 09:24
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IIRC chaos wrote in Arte/Sanity that the vector part at the end was using the CPU to draw the flatshaded polygons instead of the blitter in order to benefit from faster machines.

I was thinking about trying out an edgebuffer-based filler.
Does anyone have experience how fast/slow this is compared to blitter filling on a stock A500? What about the A1200?
jar
Member
#2 - Posted: 30 Oct 2008 16:48
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or would a CPU XOR filler be a better solution than the edgebuffer? I don't want to use a chunky buffer..
Kalms
Member
#3 - Posted: 1 Nov 2008 01:41
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Well, speaking from the A1200 perspective: If you are using the blitter or a CPU XOR solution, overlapping polygons will cause you a lot of headache. So when rendering a scene with realtime calculated 3D polygons (so it is not a 2D animation where all occluded surfaces have already been removed), I would expect a CPU solution that relies on edgebuffers (or better yet, handling all the edge stepping in registers while rendering scanlines) to perform better than a "draw all edges, then fill buffer" approach.

caveat emptor: it was more than 10 years since I did any actual coding for the plain a1200.
jar
Member
#4 - Posted: 3 Nov 2008 09:58
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Thanks Kalms. I think I will try the edgebuffer first then. But would be really interesting to know how chaos' routine worked back then.

 

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A.D.A. Amiga Demoscene Archive, Version 3.0