Mercurial > sdl-ios-xcode
annotate docs/man3/SDL_CDStatus.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 |
rev | line source |
---|---|
181
e5bc29de3f0a
Updated from the SDL Documentation Project
Sam Lantinga <slouken@libsdl.org>
parents:
55
diff
changeset
|
1 .TH "SDL_CDStatus" "3" "Tue 11 Sep 2001, 22:58" "SDL" "SDL API Reference" |
0 | 2 .SH "NAME" |
3 SDL_CDStatus\- Returns the current status of the given drive\&. | |
4 .SH "SYNOPSIS" | |
5 .PP | |
6 \fB#include "SDL\&.h" | |
7 .sp | |
8 \fBCDstatus \fBSDL_CDStatus\fP\fR(\fBSDL_CD *cdrom\fR); | |
9 \fB/* Given a status, returns true if there\&'s a disk in the drive */ | |
10 #define CD_INDRIVE(status) ((int)status > 0) | |
11 .SH "DESCRIPTION" | |
12 .PP | |
13 This function returns the current status of the given drive\&. Status is described like so: | |
14 .PP | |
15 .nf | |
16 \f(CWtypedef enum { | |
17 CD_TRAYEMPTY, | |
18 CD_STOPPED, | |
19 CD_PLAYING, | |
20 CD_PAUSED, | |
21 CD_ERROR = -1 | |
22 } CDstatus;\fR | |
23 .fi | |
24 .PP | |
25 .PP | |
26 If the drive has a CD in it, the table of contents of the CD and current play position of the CD will be stored in the SDL_CD structure\&. | |
27 .PP | |
28 The macro \fBCD_INDRIVE\fP is provided for convenience, and given a status returns true if there\&'s a disk in the drive\&. | |
29 .PP | |
30 .RS | |
31 \fBNote: | |
32 .PP | |
33 \fBSDL_CDStatus\fP also updates the \fI\fBSDL_CD\fR\fR structure passed to it\&. | |
34 .RE | |
35 .SH "EXAMPLE" | |
36 .PP | |
37 .nf | |
38 \f(CWint playTrack(int track) | |
39 { | |
40 int playing = 0; | |
41 | |
42 if ( CD_INDRIVE(SDL_CDStatus(cdrom)) ) { | |
43 /* clamp to the actual number of tracks on the CD */ | |
44 if (track >= cdrom->numtracks) { | |
45 track = cdrom->numtracks-1; | |
46 } | |
47 | |
48 if ( SDL_CDPlayTracks(cdrom, track, 0, 1, 0) == 0 ) { | |
49 playing = 1; | |
50 } | |
51 } | |
52 return playing; | |
53 }\fR | |
54 .fi | |
55 .PP | |
56 .SH "SEE ALSO" | |
57 .PP | |
58 \fI\fBSDL_CD\fP\fR | |
181
e5bc29de3f0a
Updated from the SDL Documentation Project
Sam Lantinga <slouken@libsdl.org>
parents:
55
diff
changeset
|
59 ...\" created by instant / docbook-to-man, Tue 11 Sep 2001, 22:58 |