nesdev.org

So how does the PPU actually convert sprites and background into pixels? Does it directly loop through each individual pixel on each line, then loop through tiles/sprites to calculate the final pixel that should end up in that spot? Or does it loop through each tile or sprite, draw a row of pixels a...

I'm writing a software renderer to work veeeery similar (nearly the same) to the SNES ppu but slightly(?) simpler. Indexed color graphics, 8x8 tile-based, multiple modes etc. But I am wondering for the purposes of writing this SNES like renderer, how does it actually rotate tiles? Mine draws to the ...

Yes, that was it, thank you! I'm guessing the [] means "final memory address" or something like that. I didn't know SNES had a D register as I mostly just know ASM carried over from NES...

I was trying to debug a SNES game to figure out how it worked, I set a breakpoint for the when $000BAA is read or written. When the breakpoint happened this is what I got: $81/99D7 A5 02 LDA $02 [$00:0BAA] A:0000 X:00FF Y:0040 P:envMXdiZc I'm a bit confused; how does A5 02 / LDA $02 relate to the me...

What happens if NMI code doesn't finish in time when the PPU actually starts to draw the next frame?

So if the cpu runs normal code while the ppu renders then how does it stay in sync? For example if only half of all "objects" or sprites are updated to their new positions in the cpu and then it comes time for the PPU to collect sprites to draw them then will half of the sprites be at thei...

What I meant is does the CPU run while the PPU draws the frame or what? Because the way I know lots of newer games work is by first taking input then doing game logic then rendering and then repeating that as fast as possible, the idea of cpu beginning execution when something on the gpu/ppu happens...

So the NMI is just a piece of code that automatically triggers at vblank right? If thats the case I have 2 questions: 1: Does that mean normal asm code runs asynchronously as the last or current frame is being drawn? Otherwise, wouldn't it only be able to be running during vblank as that's when it's...

Thanks guys, I got it to work by messing with Kasumi's code for 7 hours...

I got that information by using a hex editor, messing in YY-CHR, and saving over and over. Because on a blank CHR when I set pixel 0,0 to color 1 the first byte became 01, when I set pixel 0,1 to color 1 the first byte became 2, and when I set 0,0 and 0,1 to color 1 it became 3. Then I figured out t...

What I (think I) understand about the basic CHR format, not counting setting colors, for the standard 2BPP NES format, from hex viewing: Each byte acts like a vertical bitflag, e.g. 0 = nothing there, 1 = pixel on 1st row, 2 = pixel on 2nd row, 3 = pixel on 1st and 2nd row etc... And it is repeated ...

There is only one palette (read: "set/choice of colours") on the NES. The colours depicted under the "Palettes" section are all you get. Background tiles and sprites get separate palettes, but the "set/choice of colours" (that you have to choose from) are the same acro...

If one wants to swap palettes in a modern game, one would use either GLSL shaders or create multiple images with different colors. But on the NES, they obviously didn't have shaders. So how did they do it during actual rendering then? If one was to replace color pixel by pixel during drawing or draw...

dougeff wrote:What kind of game do you want to make?

I really think us SNES 'newbs' should collaborate more.

My aim isn't to make a game (at least not yet) but to reverse engineer, understand, and hack Mega Man X.

I would really like to but 65816 is gibberish to me right now I can't imagine myself understanding a decent amount it anytime soon. Hopefully within the next 5 or 6 months if I'm lucky.