kulor wrote: ↑Wed May 11, 2022 1:38 pm
Wanted to elaborate on this, because after doing some more investigation, I'm definitely convinced VRAM is not a concern for mode 5. Something to consider is that character addressing still works in 8x8 tile chunks with 16x16 tiles, so the VRAM consumption of all the unique tiles you can address per-layer is actually the same regardless of if you use 8x8 tiles or 16x16 tiles, high-res or low-res.
For example, in mode 1, let's say you want as many unique tiles as possible for each layer. For each of the 4bpp layers, you need 1024x 8x8 tiles, which are 32 bytes each, for a total of 32KB VRAM, multiplied by two for the two layers. For the 2bpp layer, the tiles are 16 bytes each, so you need 16KB for that. Grand total is 80KB of VRAM use, which is more than you actually have, so you can't actually have the maximum number of unique tiles for all layers in mode 1.
In mode 5, because it's 16x16 tiles, you only get 256 unique tiles, as well as the probably-useless half-steps between unique tiles. For the 4bpp layer, you need 256x 16x16 tiles, which are 128 bytes each, for 32KB. For the 2bpp layer, they're 64 bytes each, so it's 16KB. Grand total is just 48KB, which is actually less than mode 1!
In fact, if you had 64x32 tilemaps for each of the layers, you could theoretically fill up your VRAM with 256 unique 16x16 tiles for the 4bpp layer, 128 unique 16x16 tiles for the 2bpp layer, and have your 8KB tilemaps and 16KB sprite space too. I think it's fair to say that "mode 5 uses too much VRAM" is a myth.
Well, you can actually use 16x8 tiles in mode 5, so you can get 512 unique tiles, provided you're using a converter that doesn't mess up 16x8 tilemaps(or make the tilemap manually or run something to correct the generated tilemap).
But anyways, since mode 1 with as many unique tiles as possible (AMUTAP) takes up around 80 kiB, most games don't do all-unique tiles, though I'm not sure how much games typically spend on VRAM for background graphics in gameplay, it depends on what kind of graphics the genre and art style of the game calls for I guess. A lot of artists that worked on SNES games generally already worked on games for other tile-based consoles, so they're typically going to think in terms of making a tileset to build tilemaps out of more than in terms of cramming a bitmap into a tileset.
If no layers share tilesets with each other, and you used 16x16 for both modes, mode 5 would certainly use less VRAM than mode 1 because there's only 1 4BPP layer in the former and there's 2 4BPP layers in the latter. But this would be if you're using the same set across both modes (as in different tilesets between layers, but same tilesets between modes), so the same tiles would be bigger on mode 1 and smaller on mode 5.
I guess you could say those who argue about mode 5's VRAM usage per layer aren't coming from the perspective of an artist used to drawing tilesets, more thinking like artists used to drawing bitmaps. If someone isn't familiar with drawing art, they're probably less familiar with drawing tilesets and constructing tilemaps out of it.
93143 wrote: ↑Wed May 11, 2022 8:17 pm
Counterpoint: BG character namebase is writable during HBlank.
This doesn't
completely solve the problem, but it could be useful in certain scenarios, and it would be a lot
more useful if the SNES had more VRAM.
I've seen the Shock diskmag on SNES do this in order to fit more unique tiles in mode 5.
It is mostly text, after all.
Though I haven't tried to read it on a real console, but the diskmag went on for 2 issues.
kulor wrote: ↑Wed May 11, 2022 7:50 pm
But a battle screen background? I'm a little surprised nobody attempted it, given how many RPGs are on the thing.
I bet it'd look like RPG Maker XP but with mixels.
At least somebody in the 21st century did attempt using mode 5 for dialogue boxes, with hi-res portraits, years ago. I think the RPG it was for was fluffy.
People at the forum thread criticised it because the resolution of the dialogue boxes (especially with the portraits) did not match the resolution of the rest of the screen. If it was 1995, I'm sure people would not make these same criticisms so long as the font was still easy to read even in RF, as modern retro gamers do look at it differently with their emulators running on their crisp, sharp monitors and their consoles hooked up through RGB SCART and external $calers hooked up to HDTVs.
I have an ASD, so empathy is not natural for me. If I hurt you, I apologise.