MottZilla wrote:With PS1 you start out with 1 Megabyte of VRAM and then subtract your frame buffers from that. For a 320x240 game you lose around 307,200 bytes. So you'd lose more than a quarter of the available VRAM.
I was not trying to suggest that there was enough VRAM for all the animations. My point was that regardless of any framebuffer considerations, there was certainly enough VRAM for one frame, and that since DMA was fast enough to replace all the graphics data needed to draw one frame in much less than a frame, VRAM as such was therefore not a bottleneck.
I was attempting to demonstrate by process of elimination that the bottleneck had to be the CD interface, which then caused the game to be RAM-limited. And the PSX has nowhere near as much RAM as a SNES+S-DD1 has ROM, meaning the reason the PSX port came out choppy doesn't apply to the SNES, meaning you'd have to actually examine the problem to conclude anything about a hypothetical SNES port rather than just assuming the PSX version to be indicative.
Also, it seems my estimate of the actual likely framebuffer size ("almost 3/4 of VRAM is probably available for data") matches yours pretty closely. In fact most of your post sounds like you're agreeing with me. Was that your intention?
I'm not sure what you are talking about with triple buffering or 32-bit color. If that was in relation to PS1, I'm fairly sure there is no 32bit color and not aware of any game that would use 3 frame buffers.
What I was getting at is that even if you were to max out the amount of VRAM used by the framebuffering (triple-buffering is a thing, though I'm not sure how helpful it'd be here), there'd still be plenty left for the graphics data used to draw the frame. I was not suggesting that this was a likely approach (particularly since the Neo Geo uses 15-bit colour).
As for 32-bit, I've been reading up on the N64 lately, and I guess I just assumed that the PlayStation's true-colour mode was 32-bit. The N64 stores alpha in the framebuffer for a couple of reasons, but I guess the PSX just uses 24-bit...
The player (or players) which usually have lots of animation typically have their graphics loaded into the main work RAM and are DMAed to VRAM as needed. This sort of setup can be seen in SNES games too.
Generally that's done when software decompression is used. With uncompressed graphics, or a decompression chip like the S-DD1 that's capable of feeding DMA, there'd be no need to use WRAM for graphics.
The problem with Metal Slug (and Metal Slug X) on PS1 is obviously a lack of RAM.
Exactly. And the only reason that matters is that the CD drive is too slow and high-latency to act as proper ROM. Therefore
none of this is relevant to the SNES.
Which was my point, in opposition to TOUKO who seemed to be maintaining that the choppy animation in the PSX version somehow indicated that the game would be even worse on SNES. It very well might be, of course, but if so it would be for unrelated reasons.
But a more important question is are you thinking you'll just make your own clone of the game with modified assets? Or are you actually looking to reverse engineer the game?
The idea here would be to port the actual game as faithfully as possible; hence the talk of switching out sprite palettes with HDMA so as to be able to use more than 8.
I'm pretty sure it's a hypothetical at this point - maybe a team will come together around it someday, but I at least am certainly too busy right now. In any case I imagine Espozo would want to be involved; he started learning SNES dev with the idea of making this port himself.
There are a number of ports that could be interesting to try. This is one of them. The danmaku game I'm porting (which I won't name at this stage) is another. TIE Fighter, Thunder Force IV... psycopathicteen was poking at Gunstar Heroes at one point, but seems to be working on an original IP now... Games like Street Fighter Alpha 2 and Doom that appear to have been ported suboptimally could be interesting targets too. But these are all fairly big projects, and together with copyright issues this suggests that few would be willing to bother.
Super Road Blaster exists. It's possible it was simpler to port due to its nature as a laserdisc game with minimal interactivity, but it's at least a completed example, pulled off by one person no less...
A clone of Metal Slug with modified assets (as in real new art, not just rescaled Metal Slug art) would be massively more time-consuming than a straight port even if the art was bad.
And no matter what any SNES version of Metal Slug would pale in comparison to the original.
I'm not sure I can agree with this given the current state of the question, though I suppose it depends what you mean by "pale". Certainly it wouldn't be a perfect port. There would be far more sprite dropout as well as a lower horizontal resolution. But it's not clear to me how much worse it would need to get beyond that, because no one's tried it. With an S-DD1 there'd certainly be enough ROM...