Mercurial > sdl-ios-xcode
annotate docs/man3/SDL_CD.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_CD" "3" "Tue 11 Sep 2001, 22:58" "SDL" "SDL API Reference" |
0 | 2 .SH "NAME" |
3 SDL_CD\- CDROM Drive Information | |
4 .SH "STRUCTURE DEFINITION" | |
5 .PP | |
6 .nf | |
7 \f(CWtypedef struct{ | |
8 int id; | |
9 CDstatus status; | |
10 int numtracks; | |
11 int cur_track; | |
12 int cur_frame; | |
13 SDL_CDtrack track[SDL_MAX_TRACKS+1]; | |
14 } SDL_CD;\fR | |
15 .fi | |
16 .PP | |
17 .SH "STRUCTURE DATA" | |
18 .TP 20 | |
19 \fBid\fR | |
20 Private drive identifier | |
21 .TP 20 | |
22 \fBstatus\fR | |
23 Drive \fIstatus\fR | |
24 .TP 20 | |
25 \fBnumtracks\fR | |
26 Number of tracks on the CD | |
27 .TP 20 | |
28 \fBcur_track\fR | |
29 Current track | |
30 .TP 20 | |
31 \fBcur_frame\fR | |
32 Current frame offset within the track | |
33 .TP 20 | |
34 \fBtrack\fR[SDL_MAX_TRACKS+1] | |
35 Array of track descriptions\&. (see \fI\fBSDL_CDtrack\fR\fR) | |
36 .SH "DESCRIPTION" | |
37 .PP | |
38 An \fBSDL_CD\fR structure is returned by \fI\fBSDL_CDOpen\fP\fR\&. It represents an opened CDROM device and stores information on the layout of the tracks on the disc\&. | |
39 .PP | |
40 A frame is the base data unit of a CD\&. \fBCD_FPS\fP frames is equal to 1 second of music\&. SDL provides two macros for converting between time and frames: \fBFRAMES_TO_MSF(f, M,S,F)\fP and \fBMSF_TO_FRAMES\fP\&. | |
41 .SH "EXAMPLES" | |
42 .PP | |
43 .nf | |
44 \f(CWint min, sec, frame; | |
45 int frame_offset; | |
46 | |
47 FRAMES_TO_MSF(cdrom->cur_frame, &min, &sec, &frame); | |
48 printf("Current Position: %d minutes, %d seconds, %d frames | |
49 ", min, sec, frame); | |
50 | |
51 frame_offset=MSF_TO_FRAMES(min, sec, frame);\fR | |
52 .fi | |
53 .PP | |
54 .SH "SEE ALSO" | |
55 .PP | |
56 \fI\fBSDL_CDOpen\fP\fR, \fI\fBSDL_CDtrack\fR\fR | |
181
e5bc29de3f0a
Updated from the SDL Documentation Project
Sam Lantinga <slouken@libsdl.org>
parents:
55
diff
changeset
|
57 ...\" created by instant / docbook-to-man, Tue 11 Sep 2001, 22:58 |