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dborth / vbagx

Visual Boy Advance GX
http://wiibrew.org/wiki/Visual_Boy_Advance_GX
299 stars 39 forks source link

Corvette issues #57

Closed GoogleCodeExporter closed 9 years ago

GoogleCodeExporter commented 9 years ago 
What steps will reproduce the problem?
1. run gba rom CORVETTE
2. at game select menu and during game play the video color display 
changes to inverse color, it looks like a negative image 
3.

What is the expected output? What do you see instead?
normal video display

Does this issue occur on VBA-M r781 (http://vba-
m.ngemu.com/vbam/vbacompiles/msvc2008/VisualBoyAdvance781.7z)? If so, 
please report the issue to the VBA-M forum.
don't know

What version of the product are you using?

Please provide any additional information below.

Original issue reported on code.google.com by katiecom...@gmail.com on 18 Jan 2009 at 11:58

GoogleCodeExporter commented 9 years ago 
ran VBA-M, video is correct in VBA-M.

Original comment by katiecom...@gmail.com on 20 Jan 2009 at 9:58

GoogleCodeExporter commented 9 years ago 
WOW that's pretty trippy in the game there...yes this is an interesting one.

Original comment by dborth@gmail.com on 21 Jan 2009 at 8:43

GoogleCodeExporter commented 9 years ago 
The whole game is in graphics mode 4, which is a double-buffered 256-colour 
bitmap 
graphics mode.

The game does NOT use "mode 7" style graphics. It is purely software-rendering.

Most games don't use this graphics mode.

The bug is also present in r61. I haven't tested any versions older than that.

Original comment by Carl.Kenner@gmail.com on 13 Mar 2009 at 6:52

GoogleCodeExporter commented 9 years ago 
The bug is caused by the game trying to write to palette memory at addresses 
higher 
than 0x5000400.

The emulator wraps these writes around to the start of the range, overwriting 
the 
palette.

I can fix the problem by adding the check that the address is < 0x5000400 in 
palette 
memory writes.

HOWEVER... VBA-M, and PC versions of VBA don't have this check, yet they still 
work!

So... Something very weird is going on with this game on vba-wii which causes 
it to 
write to memory addresses that it wouldn't normally write to. Either that, or 
the BKPT_SUPPORT behaves differently on other platforms.

I have also got crashes playing this game. So there is possibly a serious 
problem 
somewhere in the GBA CPU emulation.

Anyway, I'm going to put this in as a workaround for this game, but I think I'm 
treating the symptoms rather than the cause.

Original comment by Carl.Kenner@gmail.com on 13 Mar 2009 at 8:15

GoogleCodeExporter commented 9 years ago

Original comment by Carl.Kenner@gmail.com on 26 Apr 2009 at 8:17

GoogleCodeExporter commented 9 years ago

Original comment by dborth@gmail.com on 25 May 2009 at 6:30

GoogleCodeExporter commented 9 years ago

Original comment by Carl.Kenner@gmail.com on 27 May 2009 at 8:26

GoogleCodeExporter commented 9 years ago 
[deleted comment]
GoogleCodeExporter commented 9 years ago

Original comment by dborth@gmail.com on 19 Oct 2010 at 10:06

GoogleCodeExporter commented 9 years ago

Original comment by dborth@gmail.com on 17 Apr 2011 at 7:35