Mercurial > sdl-ios-xcode
view src/video/Xext/extensions/panoramiXext.h @ 1544:ab1e4c41ab71
Fixed bug #33
Mike Frysinger wrote:
> with libsdl-1.2.9, some games (like bomberclone) started
> segfaulting in Gentoo
[...snip...]
> the last change in the last hunk:
[...snip...]
> if i change the statement to read:
> (table[which].blit_features & GetBlitFeatures()) == GetBlitFeatures()
> bomberclone no longer segfaults on my box
Alex Volkov wrote:
> The test "(table[which].blit_features & GetBlitFeatures()) ==
> table[which].blit_features)" is correct, and the previous
> "(table[which].cpu_mmx == SDL_HasMMX())" was actually broken.
I think there is potentially a slightly different cause of the above problem.
During the introduction of the Altivec code, the blit_table struct field
'alpha' got changed from a straightforward enum to a bitmask, which makes
perfect sense by itself. However, now the table driven blitter selection code
in SDL_CalculateBlitN() can choose the wrong blitters when searching for a
NO_ALPHA blitter because of the following code:
int a_need = 0;
...
(a_need & table[which].alpha) == a_need &&
When searching through the normal_blit_2[] table, a SET_ALPHA blitter (like
Blit_RGB565_ARGB8888) can now be selected instead of a NO_ALPHA one, causing
alpha channel bits to appear in a non-alpha destination surface. I suppose this
could theoretically be an indirect cause of the segfault mentioned above.
I *think* this can be fixed by changing to
int a_need = NO_ALPHA;
author | Sam Lantinga <slouken@libsdl.org> |
---|---|
date | Wed, 15 Mar 2006 15:47:49 +0000 |
parents | 585a7e1285ae |
children | 782fd950bd46 c121d94672cb |
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/* $Xorg: panoramiXext.h,v 1.4 2000/08/18 04:05:45 coskrey Exp $ */ /***************************************************************** Copyright (c) 1991, 1997 Digital Equipment Corporation, Maynard, Massachusetts. Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software. The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software. THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL DIGITAL EQUIPMENT CORPORATION BE LIABLE FOR ANY CLAIM, DAMAGES, INCLUDING, BUT NOT LIMITED TO CONSEQUENTIAL OR INCIDENTAL DAMAGES, OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. Except as contained in this notice, the name of Digital Equipment Corporation shall not be used in advertising or otherwise to promote the sale, use or other dealings in this Software without prior written authorization from Digital Equipment Corporation. ******************************************************************/ /* * PanoramiX definitions */ /* $XFree86: xc/include/extensions/panoramiXext.h,v 3.6 2001/01/17 17:53:22 dawes Exp $ */ #include "SDL_name.h" /* THIS IS NOT AN X PROJECT TEAM SPECIFICATION */ #define PANORAMIX_MAJOR_VERSION 1 /* current version number */ #define PANORAMIX_MINOR_VERSION 1 typedef struct { Window window; /* PanoramiX window - may not exist */ int screen; int State; /* PanroamiXOff, PanoramiXOn */ int width; /* width of this screen */ int height; /* height of this screen */ int ScreenCount; /* real physical number of screens */ XID eventMask; /* selected events for this client */ } SDL_NAME(XPanoramiXInfo); extern SDL_NAME(XPanoramiXInfo) *SDL_NAME(XPanoramiXAllocInfo) ( #if NeedFunctionPrototypes void #endif );