15 November 2018, 14:28 | #1 |
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New Blitter cp2
I all,
I dont' know if this technique was investingated before, and maybe left down. I only was looking to find out an new way to do so. This way is not meant to be fast, maybe it'll be, who knows. As we know cp2 is a matter of rotation, and we can do it with blitter very easily. In my humble opinion the real "problem" is porelly design hw, that are only capable to works in x direction: Why they did design hw able to work good even in y direction? Anyway, fisrt we have to set our planes pointer to interleaved way, which is some sort of y chuncky buffer, and then we have to map into them our chuncky pixel into the same direction: how to do that? With blitter, we can map 4,(4bits planes) pixels at ones, or 2, (8bits planes) pixel, just by using line drawing! Since blitter is able to map a patter into line, we have to load BLTADAT with our chuncky pixels, ad draw vertical line 16 pixels height. That's all! I dont' know if this way can be fast, maybe by using blitter + cpu + copper, someone could get the fastest possible cp2, or maybe we can do it with only cpu. Like I said, this technique it's meant only yo explore new way to do c2p Just my 2 cents |
15 November 2018, 14:41 | #2 |
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15 November 2018, 14:49 | #3 |
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15 November 2018, 14:56 | #4 | |
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Quote:
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15 November 2018, 14:57 | #5 |
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My fault, was BLTBDAT. Like I said, just to try an exotic way to do cp2!
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15 November 2018, 16:41 | #6 |
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IIRC, somebody has mentioned doing chunky->planar conversion using blitter line mode here on EAB before..
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16 November 2018, 08:04 | #7 |
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16 November 2018, 08:12 | #8 |
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16 November 2018, 09:45 | #9 |
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Especially when using the CPU you don't want to be setting individual bits at a time, but rather use large chunks (like the cpu c2p's are already doing).
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16 November 2018, 12:31 | #10 |
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16 November 2018, 12:56 | #11 |
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16 November 2018, 16:23 | #12 |
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16 November 2018, 16:28 | #13 |
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16 November 2018, 16:49 | #14 |
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Which is way too slow. For a 160x100 pixels screen this would already amount to 512000 cycles, which is over 3 frames, and this is just the conversion. So unfortunately it's way slower than currently used methods.
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03 December 2018, 09:32 | #15 |
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Just uploaded in the zone! my demo. Feel free to use it, and if someone need help, I'm here!
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03 December 2018, 15:02 | #16 |
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03 December 2018, 15:36 | #17 |
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03 December 2018, 15:42 | #18 |
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03 December 2018, 20:01 | #19 |
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Alright, only tried it in WinUAE, and the executable crashes on a standard A500-configuration. It did work with an expanded conf though, so I was able to run it. I must admit I was hoping to see at least something move
I hope this was a good exercise for you, as you probably now see why this isn't a very efficient way of doing a c2p conversion. You should probably leave this approach alone now, and for example try making a more traditional blitter c2p next. |
03 December 2018, 22:16 | #20 | |
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Quote:
Last edited by sandruzzo; 03 December 2018 at 22:27. |
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