Mercurial > sdl-ios-xcode
view src/video/xbios/SDL_xbios_sb3.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 | d910939febfa |
| children | 782fd950bd46 c121d94672cb a1b03ba2fcd0 |
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/* SDL - Simple DirectMedia Layer Copyright (C) 1997-2004 Sam Lantinga This library is free software; you can redistribute it and/or modify it under the terms of the GNU Library General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version. This library is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Library General Public License for more details. You should have received a copy of the GNU Library General Public License along with this library; if not, write to the Free Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA Sam Lantinga slouken@libsdl.org */ #include "SDL_config.h" /* ScreenBlaster 3 definitions Patrice Mandin */ #ifndef _SDL_xbios_sb3_h_ #define _SDL_xbios_sb3_h_ /*--- Defines ---*/ #ifndef C_SCPN #define C_SCPN 0x5343504EL #endif #define SCPN_DEV_1BPP 0 #define SCPN_DEV_2BPP 1 #define SCPN_DEV_4BPP 2 #define SCPN_DEV_8BPP 3 #define SCPN_DEV_16BPP 4 extern const int SDL_XBIOS_scpn_planes_device[]; /*--- Types ---*/ typedef struct { unsigned short virtual_width; /* Virtual screen width */ unsigned short virtual_height; /* Virtual screen height */ unsigned short visible_width; /* Visible width */ unsigned short visible_height; /* Visible height */ unsigned short h_pos; /* Horizontal position in virtual screen */ unsigned short v_pos; /* Vertical position in virtual screen */ unsigned short dummy; unsigned long size; /* Size of screen in bytes */ unsigned short device; /* Device number to find planes = getRez() */ /* = Index in scpn_planes_device[] */ } __attribute__((packed)) scpn_screeninfo_t; typedef struct { unsigned long magic; /* just a BRA assembler jump */ unsigned short version; void *dummy1; unsigned short ptsout0_1; unsigned short ptsout0_2; unsigned short dummy3; unsigned char date[8]; /* Date of program build */ unsigned char asm_string[30]; /* 10 times the 'ASM' string */ unsigned short dummy4; scpn_screeninfo_t *screen_info; unsigned short dummy6; } __attribute__((packed)) scpn_cookie_t; /*--- Function prototypes ---*/ int SDL_XBIOS_SB3Usable(scpn_cookie_t *cookie_scpn); void SDL_XBIOS_SB3Init(_THIS, scpn_cookie_t *cookie_scpn); #endif /* _SDL_xbios_sb3_h_ */