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Bug 3000

Summary: [OS X 10.6] change 9622 causes 8-bit color modes to be used for fullscreen
Product: SDL Reporter: Eric Wasylishen <ewasylishen>
Component: videoAssignee: Ryan C. Gordon <icculus>
Status: RESOLVED FIXED QA Contact: Sam Lantinga <slouken>
Severity: normal    
Priority: P2 CC: icculus, sezeroz
Version: HG 2.0Keywords: target-2.0.4
Hardware: x86   
OS: Other   

Description Eric Wasylishen 2015-06-03 22:52:31 UTC 
Hi,
With this change, I'm getting 8-bit color in fullscreen mode on OS X 10.6:
https://hg.libsdl.org/SDL/rev/fb91c22f656b

Can be reproduced with the 'testgl2' sample. When you enter fullscreen with Ctrl+Enter, there are strong dithering artifacts that look like 8-bit.

It doesn't happen on 10.7 or newer.



What appears to be happening is, in GetDisplayMode:
- 'fmt' is IO8BitIndexedPixels
- bpp is set to 0 on line 155: "bpp = 0;  /* ignore 8-bit and such for now. */"
- Then in the switch below, bpp 0 hits the /* Totally unrecognizable format */ case, and is reported falsely as SDL_PIXELFORMAT_ARGB8888.


I haven't debugged outside of this function, but presumably SDL is deciding to use this fake SDL_PIXELFORMAT_ARGB8888 mode that is actually 8-bit paletted.


I would either revert change 9622, or add the following on line 151:

else if (CFStringCompare(fmt, CFSTR(IO8BitIndexedPixels), kCFCompareCaseInsensitive) == kCFCompareEqualTo) {
   bpp = 8;
}

However, with that fix, I worry that another unusual format listed in IOGraphicsTypes.h might come up and trigger the same kind of bug.
Comment 1 Ryan C. Gordon 2015-06-04 00:38:58 UTC 
Crap.

--ryan.
Comment 2 Ryan C. Gordon 2015-06-04 06:13:26 UTC 
Backed out the problem changes in https://hg.libsdl.org/SDL/rev/1c0e96906974

--ryan.