Discussion

Is LowresNX based on game consoles with CPU-based graphics?

1

SP4CEBAR 2021-11-23 21:17

I've just watched this video from computerphile about CPU-based graphics on early game consoles. Since LowresNX has raster calls, does that mean that it's based on one of those game consoles?


nathanielbabiak 2021-11-23 21:35

Yes, it's a combination of the Commodore 64 and the (original) Nintendo Game Boy.


Timo 2021-11-24 09:25

I think the Atari 2600 (see video) didn‘t have a real video chip at all, so the CPU really HAD to prepare every scanline.
That‘s not the same on LowRes NX, the Game Boy and the C64. You CAN use the CPU to modify each scanline, but you don‘t have to.


SP4CEBAR 2021-11-24 12:44

That makes sense, thanks for the answers!


moechofe 2021-11-26 23:15

The fantasy console emulated by the lowresnx program actually did simulate a PPU like in the real gameboy.

the screen is 160x128, so 20480 pixels in total for only 2 color.
LRNX has a total of 64 possibles colors, a frame buffer for all those will cost 122880 bytes (6 bits plan)
LRNX can only address 65536 bytes of memory, it will not fit.
That why the PPU exists, by grouping the pixels by block of 8x8 and by reducing the number of color per blocks to 4, and finally adding the hardware sprite and bg mechanics, it's possible to create really good game.


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