CPS video emulation

I don't really know anything about how CPS1/2/3 work, but you can always check the MAME source or ask a MAME dev

EDIT: Stupid me, you just said you looked at MAME's code aperbag:

AamirM said:

Hello all,

I am writing my own Neogeo, CPS1/2 emulator. A beta version is available at:

http://www.mytempdir.com/2022594

Neogeo core is finished(almost) and all the games except encrypted ones run fine. Now I am starting the CPS1 core. I have figured out most of the stuff(thanks to MAME) but I am somwhat confused about the video stuff. I don't understand the follwoing:

1) How to find the total number of sprites, and scroll1/2/3 tiles?

2) Whats the difference between a scroll base and scroll base code?(which is used in Callice drv files)

3) Can someone give me a general overview of the tilemap(scrolls) drawing or point me to some doc?

stay safe,

AamirM

Click to expand...

I haven't done anything with CPS but I found this:

http://arcadedev.emuvibes.com/documents/cps1.html

Also, this is sourcecode to a couple CPS games/demos:

http://frogfeast.rastersoft.net/CPS1Src.html
http://arcadedev.emuvibes.com/files/cps1demo.zip

This is what I could gather with regard to your quetsions...

1) 256 sprites maximum, last sprite will have an 0xFF00 attribute field. I think that the scrolls have fixed tile sizes and tile map dimensions each. scroll 1 seems to be 64 tiles wide (8x8 large tiles), scroll 2 32 tiles wide (16x16 large tiles), so maybe scroll 3 is 16 tiles wide (32x32 large tiles). That'd make them all 512 pixels wide, and the height seems to be the same.

2) No idea >_> I only see scroll base in the docs/sourcecode which is of course the location of where the scroll maps start in VRAM.

3) Apparently it's stored in planar format (as usual for this). 16 colors per tile/sprite and 32 palettes, so you get 512 colors each - scroll1, scroll2, scroll3, and the sprites each have their own palette of 512 colors. So 2048 colors total. The exact storage of the tiles I'm not really sure about, something about banks... unfortunately all of the tile data in the code is hardcoded and not dynamically created so it's difficult to tell.

The tilemap appears to consist of 2 bytes per tile entry, the docs I linked don't tell you this but those other bits are for the tile number. At the very least it works this way for scroll 1. Again, I don't know where the actual tiles are stored :/ There may only be 256 of them (or 512, or 128 for scroll 2) It's possible that it's stored after the tilemap in the scroll* RAM offset. I speculate this because in the source I've seen they're spaced out much further than they have to be for just the map.

I'm sure emu source code will fill in all the details. There's one CPS emulator for handhelds by someone named NJ, that has source available.. maybe that could help you more. Good luck.

Hello, your link went offline.

I'd like to try out your emulator, how far have you come?

very interested in working cpu cores

Thanks,
Michael