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Roms

PostPosted: Tue Aug 25, 2020 9:39 am
by Ian
Was talking with Bart a while ago about the Japanese version of scud race which has corrupted 2d graphics. Was too lazy to load it and make a screenshot but here is mame

Image

Interestingly it has the same bug. But I would assume the mame tilegen code is very mature because its used for system32/model2 etc?

Was wondering is the rom bad? Removing the patches they seem to fail the CRC check

Image

Magical truck adventure also blows up in attract mode. I had long suspected it could have been also corrupted.

Might it be worth trying to get some of these games re-dumped?

Re: Roms

PostPosted: Tue Aug 25, 2020 11:26 am
by Bart
Scud Race does not have a CROM3. :) I'm not sure what is supposed to be reflected in those addresses or whether Scud Race even accesses them. I would expect it to return all 1's but filling the memory with 0xFF neither fixes the ROM test nor changes what happens with the tile maps, so I don't think the ROMs are involved.

I wish nuexzz could explain his rationale for developing that patch and how he deduced the value. That would help a lot. My best guess is that the game is reading some sort of register somewhere and indexing the wrong palette.