How are NES graphics laid out?
I assume you mean in the CHR ROM, right? NES CHR graphics are 2 bitplanes deep. That means that all graphics can be made up of a total of 4 colours. Each tile takes up 16 bytes of data: 8 bytes for the first plane, and 8 for the second. The layout for each plane is the same as any bitmapped 8×8 image: the first byte is a binary representation of the 8 pixels in the first line of graphics; the second byte the same for the second line, and so on. The two bitplanes for each character are stored sequentially, but are combined by the NES to produce a 4-colour tile. • How does palette mirroring work? Palette entry 0 is GOD. It is the most important entry because it determines the background colour, defines transparency for background and sprites, and is mirrored across the palette table. The PPU’s palette table goes from $3F00-$3F1F in its memory. Palette entry 0 is $3F00. But because of mirroring, any changes that you make to $3F00 also directly change $3F10, and vice-versa. Every 4 bytes i
