tepples wrote:
But then the GBC has a sh*tload more RAM than the NES and most mappers provide, namely 32 KB CPU RAM (four banks of 8 KB) and 16 KB of VRAM (two banks of 8 KB). With that much memory, it can copy the dictionary from one bank to RAM, switch to the bank with the map, and then decompress using that.
That'd typically be thinkable with a RPG using SRAM at $6000-$7fff. Also, it would allow dynamic tables and dictionnaries, possibly adding more depht. Tough, most of the SRAM space should be left for un-compressed maps and gamaplay variables that may be saved.
Quote:
The perceived GBC advantage may be a function of one or more the following:
- GBC video has a sh*tload of hblank time into which to fit writes to VRAM.
- GBC video is only 160x144 out of a 256x256 single-screen-mirrored plane, meaning that there's a lot of offscreen space in each nametable, so there isn't as much to worry about with effects at the seam.
- The GBC video model resembles MMC5 ExGrafix with CHR RAM, so there's little need for monkeying around with bitwise operations on attribute tables.
- The Game Boy has a hardware "window" to a second nametable and a scanline interrupt that resembles that of MMC5, allowing for versatile splits.
- The GBC CPU is roughly twice as fast as the NES CPU. (An 8 MHz Z80 is roughly as powerful as a 4 MHz 6502.)
- Updating palettes in hblank is easy, giving some programs almost Super NES-like backgrounds.
Wow ! I didn't know all of theese. I asked myself many many times why GBC games have so, so much better graphics than NES games with the same bitdepht.
I think GBC also can hanldle the sprite priority bit on background map instead of just spries as the NES does, so this makes layering much easier to handle, isn't it ?
Unfortunately there is much less doccuments available on Game Boy (not Advance) hardware for an unknow reason. There is general purpose doccuments, but none of theese goes in detail.
Also, lot of GBC games (the ones wich aren't in a transparent cartcase) are backward compatible with older monochrome Game Boys, and so they have less VRAM and stuff.