Mercurial > sdl-ios-xcode
view docs/man3/SDL_CDOpen.3 @ 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 | e5bc29de3f0a |
children | 546f7c1eb755 |
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.TH "SDL_CDOpen" "3" "Tue 11 Sep 2001, 22:58" "SDL" "SDL API Reference" .SH "NAME" SDL_CDOpen\- Opens a CD-ROM drive for access\&. .SH "SYNOPSIS" .PP \fB#include "SDL\&.h" .sp \fBSDL_CD *\fBSDL_CDOpen\fP\fR(\fBint drive\fR); .SH "DESCRIPTION" .PP Opens a CD-ROM drive for access\&. It returns a \fI\fBSDL_CD\fR\fR structure on success, or \fBNULL\fP if the drive was invalid or busy\&. This newly opened CD-ROM becomes the default CD used when other CD functions are passed a \fBNULL\fP CD-ROM handle\&. .PP Drives are numbered starting with 0\&. Drive 0 is the system default CD-ROM\&. .SH "EXAMPLES" .PP .nf \f(CWSDL_CD *cdrom; int cur_track; int min, sec, frame; SDL_Init(SDL_INIT_CDROM); atexit(SDL_Quit); /* Check for CD drives */ if(!SDL_CDNumDrives()){ /* None found */ fprintf(stderr, "No CDROM devices available "); exit(-1); } /* Open the default drive */ cdrom=SDL_CDOpen(0); /* Did if open? Check if cdrom is NULL */ if(!cdrom){ fprintf(stderr, "Couldn\&'t open drive: %s ", SDL_GetError()); exit(-1); } /* Print Volume info */ printf("Name: %s ", SDL_CDName(0)); printf("Tracks: %d ", cdrom->numtracks); for(cur_track=0;cur_track < cdrom->numtracks; cur_track++){ FRAMES_TO_MSF(cdrom->track[cur_track]\&.length, &min, &sec, &frame); printf(" Track %d: Length %d:%d ", cur_track, min, sec); } SDL_CDClose(cdrom);\fR .fi .PP .SH "SEE ALSO" .PP \fI\fBSDL_CD\fR\fR, \fI\fBSDL_CDtrack\fR\fR, \fI\fBSDL_CDClose\fP\fR ...\" created by instant / docbook-to-man, Tue 11 Sep 2001, 22:58