Re: Max colour output
Posted: Sun Sep 23, 2018 4:20 am
Yeah. Even with dither the 4x4x4 picture isn't nearly as good as 5x5x5. I guess I was wrong.
NES Development and Strangulation Records message boards
The bunny picture, when scaled down to 256x224 and truncated to 15bpp, has 2k unique colors in it. Yes, that's "only" 1/16th of the full gamut. It's also 8x256.Molive wrote:However if you really wanted to show off the 4-4-4 colour space you'd have to use a really high colour image which ends up using more than 256 colours from that space. Currently the bunny one probably uses less than the one from the pallette mode.
Including everything but the most powerful arcade machines even; it's weird how feature packed the SNES was in comparison to most everything else for how starved for bandwidth it is...93143 wrote: It would probably have cost more silicon than they wanted to spend on a feature that was already way beyond anything their competition could do...
Yup; just look at how the sky gradient in the first level of DKC jitters up and down for blending. 12bit color is much better than 9bit color, but even it can be pretty ugly. Just look at how the only upgrade beside sound hardware that Capcom made with the CPS2 was upgrading the color from 12bit to 16bit. (12RGB with an additional 4bits of brightness; probably easier to implement or something...)psycopathicteen wrote:I could still can tell shades between colors in 15-bit colors most of of the time.
Tiles of 128 bytes for a machine with less than a resulting 6KB of bandwidth (6,32KB, but WRAM, OAM, CRAM), seems a little bit insufficient to me.Drew Sebastino wrote:This is hypothetical and thus not useful, but the sad thing is, if the SNES had 128KB of VRAM as originally intended, the S-PPU could have been made to support something like a 16bpp bitmap mode, as it has just enough graphics bandwidth. (Although you'd only have 8KB for sprites, assuming the bitmap is 256x224.
Edit: 16KB for sprites; I forgot that while you'd only have 1/8 of total VRAM, you would have 128KB instead of 64KB.
Yes, presumably the WRAM forces the DMA to adapt its frequency to 2,68mhz, i don't know if the DMA actually works at 3,58mhz of stock.creaothceann wrote:Wasn't the restriction to 2.68MHz because of the slow ROM chips of the day + the 8-bit data bus?
The SA-1 of the cartridges has an 16 bit bus data to comunnicate with the internal ram of the own cartridge.creaothceann wrote:A 16-bit data bus is needed, but that doesn't seem possible with a stock 65c816 CPU.
I actually got a pretty decent processor going with several days of work that does that harmonious quantization you're wondering about.93143 wrote:You can of course change up to 8 arbitrary CGRAM entries per scanline with HDMA. A few years ago I wrote a scheduler in Matlab that starts with the top 256 colours (or fewer if I need space for something else) and goes down the picture changing palette entries that aren't currently needed when out-of-palette colours show up. If it can't find a free HDMA slot, or a single line has too many colours for the palette, it fails and I have to go re-quantize to a lower total colour count and try again. Obviously it would be better to have a tool that simultaneously optimizes the image and schedules the HDMA, but that seems like a lot of work...
Code: Select all
// check if hdmaCandidate's final scanline is before our first possible scanline // this only takes into account bucket pairs that are like so: // -|||-------|||----- <- Bucket - split this along the scanline // ------|||---------- <- hdmaCandidate? // check if hdmaCandidate's first non-gap sequence (that we can see) is within // bucket's gap. this takes into account bucket pairs like so: // -|||-------|||----- <- Bucket // ------|||------|||- <- hdmaCandidate?
The 15bpp images are only provided for reference/comparison, as per lidnariq's request.Señor Ventura wrote:That 15bpp are really possible in snes?, How many KB's occupies?.
So, the two of the snes are the two of the right, right?.CypherSignal wrote:The 15bpp images are only provided for reference/comparison, as per lidnariq's request.Señor Ventura wrote:That 15bpp are really possible in snes?, How many KB's occupies?.