17 December 2020, 23:23 | #381 |
Pixelglass/Reimagine
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Just note that C2P can also be done with the Blitter, as KK/Altair demonstrated with his recent a500 Doom engine. With quite an impressive performance output as well.
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18 December 2020, 11:20 | #382 | |
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There used to be an option for that in the form of the Graffiti card that plugged into the video output of the Amiga, but being a 3rd party and external device it sadly saw rather low use. Apparently, Commodore was offered a license to include Graffiti as an on-board chip around the time AGA was being designed, but they didn't want to pay the license fee/production costs so it didn't happen.
I've defended the A1200/AGA in the past (mostly because the A1200 is by far my favourite Amiga ), but it's hard to deny that not including any form of chunky mode in AGA was a really foolish move by Commodore. Quote:
Don't know how fast, but it's one of the reasons that DoomAttack runs better than say ADoom on my A1200/030. |
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18 December 2020, 12:20 | #383 |
Lemon. / Core Design
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Not sure if c2p is any benefit for just flat shaded polygons? The 030 should be able to render these pretty quickly to bitplanes? or am I missing something here....
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18 December 2020, 12:53 | #384 |
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Like DanScott said, what do you do with a c2p, if the plan was to make a flatshaded polygon game? Even on a 68000 system, the CPU is not much slower than the blitter in drawing filled polygons on screen, when we are not talking about special cases (like just one large polygon on screen, no background gfx, where blitter will win easily, just look at some demos).
There is no advantage in filling scanlines with chunky pixels in fast ram and then transfer that into chip ram with a slow c2p, when you can fill directly into chip ram with CPU, and even hide the latency of slow chip ram writes with some code coming after chip ram writes. Of course, doing the scanline fill with CPU in planar mode requires some special code that is highly optimized, but it has been done before even on 68000 systems. |
18 December 2020, 13:16 | #385 |
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I could see a benefit for a scene with lots of smaller polygons, those are quite inconvenient in planar modes - e.g. a 10 pix wide polygon needs 16-32 memory accesses per horizontal span in 8 bit planar mode, compared to 3 to 5(?) in chunky mode. But probably you would be limited by the 3D transformation throughput way before you reach such a level of detail.
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18 December 2020, 13:17 | #386 |
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I wonder if there's a way to use the Blitter such that faster CPU's benefit more (for instance, clear the screen using the Blitter while your CPU is busy in fast memory doing calculations to prep the drawing). It seems to me you might be able to increase concurrency that way.
Similarly, perhaps (though I'm not too clear on this) it may be faster to draw say 1BPL polygons in buffers in fast ram and transferring these over. Though that would require some creative way to prevent copying a full rectangle when only part is filled. Then again, I have little experience with 3D on the Amiga. Just considering how you might reach better CPU usage. |
18 December 2020, 14:10 | #387 |
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Dan and the other ^demogroup people are probably best placed to answer this.
DAN: You could always use 'celebrandil mode' |
18 December 2020, 14:10 | #388 | |
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Quote:
Yes, small polygons are faster to render with chunky pixels, but there is also a problem of color wasting, you don't need a 8 bit palette, and on the Amiga the c2p is going to cost a lot to per frame. Plus the problem that you can't use the blitter for the clearing of previous frame with a c2p. With a planar renderer, you're also not going to see 8 planes being used, but rather half of that or less (even 2-3). With larger polygons, planar rendering should be faster than with chunky pixels, because of the more efficient color usage. |
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22 December 2020, 20:57 | #389 |
J.M.D - Bedroom Musician
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Ok so just to be on the same page, are you telling me that a base 500 cannot do a game like Ballz? After all the vectorball stuff shown by demos? (i know that one thing is rotate something on screen and another is having interact in a 3D space but pleez!)
There is also the Ellipsoid route, used on this sorta-Alone in the dark on Dos in 1994 hence still on a viable calculation window [ Show youtube player ] |
24 December 2020, 18:42 | #390 | ||
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Quote:
If you have to hold Akiko's hand every 32 pixels then the Host CPU cost is quite ridiculously enormous and as Samurai Crow pointed out, 030 is faster (unsurprising, given the 32-px inner loop). Quote:
I was merely curious what kind of 3D scene is possible at 60 fps - mostly from Jaguar perspective - where I can initiate ClearScreen call on a Blitter, in parallel with GPU rasterizing last frame's polygons, in parallel with DSP doing 3D transform and clipping and writing to the double buffered polygon list, in parallel with 68000 handling input,AI and everything else. This way you can actually get some useable 3D scene at 60 fps. Of course, on Amiga, you only have one CPU and a Blitter and you must switch bitplanes, so you can't really get a fullscreen refresh 60 fps 3D on slower CPUs like 030. Probably with 2-3 bitplanes, and just a partial screen redraw, it might work on 030 - say a driving game where half screen is a cockpit and only about 40% is 3D viewport. I'm wondering if 040 is fast enough for that (060 is, for sure)... |
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24 December 2020, 18:44 | #391 | |
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Quote:
I think it can - it doesn't have to run at 50fps. Ballz is ok but better to try to emulate Super FX Fighter on the SNES. That's a step towards Virtua Fighter at least. |
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24 December 2020, 18:56 | #392 | |
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Quote:
I have a flatshader codebase running on 5 different HW platforms across multiple different resolutions, but sadly none of them has bitplanes, like Amiga. Technically, I have a flatshader running on Amiga / Vampire (dev against 040 WinUAE config) it's just framebuffer-based and relies on CyberGraphX methods to display my framebuffer. I suppose, I could just implement a C2P instead and not have to rely on CGX. I would have to first implement it and then extensively benchmark to see where exactly is the threshold of the scene complexity between C2P and bitplane switch. Last edited by VladR; 24 December 2020 at 18:57. Reason: Typos |
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31 December 2020, 05:58 | #393 |
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Forget VF... who needs it when we have IK+ ? If you can't drop your trousers, then it's not a proper fighting game! ??
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21 May 2021, 06:35 | #394 |
J.M.D - Bedroom Musician
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Getting for one moment back in the subject of Motion Capture, this demo came out last Revision and uses it properly on OCS/ECS
[ Show youtube player ] |
30 November 2021, 17:50 | #395 |
J.M.D - Bedroom Musician
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