Reip MAMEWIP - Namco NA1 fixes
Reip has posted some news regarding his developments on Namco NA1 arcade hardware emulation for MAME:
30 / 03 / 2008
Namco NA1 fixes (Part II)
I’ve found how tilemaps switch from 8bpp to 4bpp, so bug (d) is completely fixed and I found that sprites can switch to 4bpp mode as well. I implemented it but it didn’t fix bug (e), it only fixed a little scroll effect in the high-score screen.
29 / 03 / 2008
Namco NA1 fixes
It’s been a while since I’ve updated this little page, indeed I haven’t had much time for MAME lately, but some days ago I noticed this bug at MAMETesters.
I decided to take a look at it, because it was probably a simple fix: a missing sprites wrap around. In fact I fixed it rewriting the sprites drawing function and simplifing it a bit.
While working on namcona1 driver I noticed that Emeraldia have some problems:
a) a hack to draw sprites with shadow bit set
b) a missing dolphin “speaking” in the demo
c) an unimplemented ROZ effect
I asked a couple of MAME-friends if they had a pcb. Luckily Stefan Lindberg has one and got a video of Emeraldia, showing all these problems plus two new ones:
d) the high-score text has wrong colors
e) text sprites in the game (the score for example) have wrong colors
f) the service mode has a lower screen resolution
I started to take a look at some of these bugs.
I got bug (a) fixed: the shadows have to be drawn only when sprites use the 16th color and not always…
before
after
…and bug (d) almost fixed: it was graphics color granularity problem, because the game can switch it (from what I can tell it can use 4bpp and 8bpp). I still have to find how to switch it and not hardcode it.
before
after
Bug (b): I know that the dolphin sprite is drawn… but it’s under the tilemaps so right now it’s not visible. I don’t know yet how to fix it. It could be related to a priority issue.
Bug (c): don’t know anything about it… there’re registers to hook it up, but I don’t know how easy or difficult it’s to implement.
Bug (e): I think it could be something related to bug (d)
Bug (f): there are probably some video registers to dinamically change screen resolution at run-time.
