Mercurial > sdl-ios-xcode
annotate docs/man3/SDL_WasInit.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_WasInit" "3" "Tue 11 Sep 2001, 23:00" "SDL" "SDL API Reference" |
0 | 2 .SH "NAME" |
3 SDL_WasInit\- Check which subsystems are initialized | |
4 .SH "SYNOPSIS" | |
5 .PP | |
6 \fB#include "SDL\&.h" | |
7 .sp | |
8 \fBUint32 \fBSDL_WasInit\fP\fR(\fBUint32 flags\fR); | |
9 .SH "DESCRIPTION" | |
10 .PP | |
11 \fBSDL_WasInit\fP allows you to see which SDL subsytems have been \fIinitialized\fR\&. \fBflags\fR is a bitwise OR\&'d combination of the subsystems you wish to check (see \fI\fBSDL_Init\fP\fR for a list of subsystem flags)\&. | |
12 .SH "RETURN VALUE" | |
13 .PP | |
14 \fBSDL_WasInit\fP returns a bitwised OR\&'d combination of the initialized subsystems\&. | |
15 .SH "EXAMPLES" | |
16 .PP | |
17 .nf | |
18 \f(CW | |
19 /* Here are several ways you can use SDL_WasInit() */ | |
20 | |
21 /* Get init data on all the subsystems */ | |
22 Uint32 subsystem_init; | |
23 | |
24 subsystem_init=SDL_WasInit(SDL_INIT_EVERYTHING); | |
25 | |
26 if(subsystem_init&SDL_INIT_VIDEO) | |
27 printf("Video is initialized\&. | |
28 "); | |
29 else | |
30 printf("Video is not initialized\&. | |
31 "); | |
32 | |
33 | |
34 | |
35 /* Just check for one specfic subsystem */ | |
36 | |
37 if(SDL_WasInit(SDL_INIT_VIDEO)!=0) | |
38 printf("Video is initialized\&. | |
39 "); | |
40 else | |
41 printf("Video is not initialized\&. | |
42 "); | |
43 | |
44 | |
45 | |
46 | |
47 /* Check for two subsystems */ | |
48 | |
49 Uint32 subsystem_mask=SDL_INIT_VIDEO|SDL_INIT_AUDIO; | |
50 | |
51 if(SDL_WasInit(subsystem_mask)==subsystem_mask) | |
52 printf("Video and Audio initialized\&. | |
53 "); | |
54 else | |
55 printf("Video and Audio not initialized\&. | |
56 "); | |
57 \fR | |
58 .fi | |
59 .PP | |
60 .SH "SEE ALSO" | |
61 .PP | |
62 \fI\fBSDL_Init\fP\fR, \fI\fBSDL_Subsystem\fP\fR | |
181
e5bc29de3f0a
Updated from the SDL Documentation Project
Sam Lantinga <slouken@libsdl.org>
parents:
55
diff
changeset
|
63 ...\" created by instant / docbook-to-man, Tue 11 Sep 2001, 23:00 |