Great write-up! Pondering this question is the thing that brought my into software development in the first place. are actually designed, and graphics were drawn by an artist, they aren't using some arbitrarily picked mathematical function chosen because it looked cool. The way demoscene works is that most things are using procedural generation, meanwhile the levels in Super Mario Bros. Some tricks are used to reduce the number of necessary tiles - for instance, clouds are the same thing as bushes, just with a different palette applied.Ĥ. Palettes are used to not restrict the entire game to 2bpp - note that 16x16 blocks have different color palettes. However, as the graphics are 2bpp, they don't use as much space. Graphics aren't compressed as they are stored in CHR ROM, and are directly accessed by the PPU (PPU cannot access RAM). Y positions bigger than 0b1011 are used for special commands (as such parameters would be rendered out of bounds).ģ. uses two bytes per object, representing the following information: XXXXYYYY PSSSVVVV, where X is horizontal position within the page, Y is vertical position within the page, P moves to the next page, S is a command, and V is its parameter (length or number of an extended object).
Rather, the game uses commands like "from now on, use this ground fill pattern", "draw pipe here", "put a staircase", "put a goal".
Levels don't use RLE or LZ77, that would use too much space. That said, I suppose if you were to compress the ROM, you probably would end up with value like 31KB.Ģ. is 40KB (PRG ROM is 32KB, and CHR ROM is 8KB).
0 kommentar(er)
