FDS or not to FDS

Discuss technical or other issues relating to programming the Nintendo Entertainment System, Famicom, or compatible systems. See the NESdev wiki for more information.

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lidnariq
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Re: FDS or not to FDS

Post by lidnariq »

NTSC is 8:7 PAR, moderately close to square.

PAL is ~7:5 PAR, closest to NTSC VIC20 narrow/C64 wide pixels.

edit: braino
Last edited by lidnariq on Wed May 10, 2017 12:46 am, edited 1 time in total.
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rainwarrior
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Re: FDS or not to FDS

Post by rainwarrior »

lidnariq wrote:NTSC is 8:7 PAR, moderately close to square.

PAL is ~8:5 PAR, closest to NTSC VIC20 narrow/C64 wide pixels.
8:5? I didn't think it was quite that wide. The wiki says ~1.3862:1 ?
AWJ
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Re: FDS or not to FDS

Post by AWJ »

The NES pixel clock is ~5.3 MHz, the C64 pixel clock is ~8 MHz. One NES pixel is almost exactly 1.5 times the width of a C64 hires pixel.
tepples
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Re: FDS or not to FDS

Post by tepples »

NTSC NES PAR is 8:7; NTSC C64 PAR is 3:4. Compare to about any other 240p platform you can think of
Oziphantom
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Re: FDS or not to FDS

Post by Oziphantom »

NDS 6328125:5767168
snort...

Nice link, tepples.
If only it covered 288p as well ;)
AWJ
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Re: FDS or not to FDS

Post by AWJ »

PAL NES and PAL C64 both have slightly fatter pixels than the respective NTSC machines, but the ratio between them is nearly the same. 2 NES pixels = 3 hires C64 pixels on both NTSC and PAL.

For your VRAM blitting, you can improve on Tepples' generic stack-based blitter by using two specialized, fully-unrolled blitters: one that always blits 24 nametable and 6 attribute bytes for scrolling, and one variable-length blitter for moving platforms, optimized for whatever range of lengths those platforms come in.
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