Mercurial > sdl-ios-xcode
annotate docs/man3/SDL_GLattr.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 |
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181
e5bc29de3f0a
Updated from the SDL Documentation Project
Sam Lantinga <slouken@libsdl.org>
parents:
55
diff
changeset
|
1 .TH "SDL_GLattr" "3" "Tue 11 Sep 2001, 23:01" "SDL" "SDL API Reference" |
0 | 2 .SH "NAME" |
3 SDL_GLattr\- SDL GL Attributes | |
4 .SH "ATTRIBUTES" | |
5 .TP 20 | |
6 \fBSDL_GL_RED_SIZE\fP | |
7 Size of the framebuffer red component, in bits | |
8 .TP 20 | |
9 \fBSDL_GL_GREEN_SIZE\fP | |
10 Size of the framebuffer green component, in bits | |
11 .TP 20 | |
12 \fBSDL_GL_BLUE_SIZE\fP | |
13 Size of the framebuffer blue component, in bits | |
14 .TP 20 | |
15 \fBSDL_GL_ALPHA_SIZE\fP | |
16 Size of the framebuffer alpha component, in bits | |
17 .TP 20 | |
18 \fBSDL_GL_DOUBLEBUFFER\fP | |
19 0 or 1, enable or disable double buffering | |
20 .TP 20 | |
21 \fBSDL_GL_BUFFER_SIZE\fP | |
22 Size of the framebuffer, in bits | |
23 .TP 20 | |
24 \fBSDL_GL_DEPTH_SIZE\fP | |
25 Size of the depth buffer, in bits | |
26 .TP 20 | |
27 \fBSDL_GL_STENCIL_SIZE\fP | |
28 Size of the stencil buffer, in bits | |
29 .TP 20 | |
30 \fBSDL_GL_ACCUM_RED_SIZE\fP | |
31 Size of the accumulation buffer red component, in bits | |
32 .TP 20 | |
33 \fBSDL_GL_ACCUM_GREEN_SIZE\fP | |
34 Size of the accumulation buffer green component, in bits | |
35 .TP 20 | |
36 \fBSDL_GL_ACCUM_BLUE_SIZE\fP | |
37 Size of the accumulation buffer blue component, in bits | |
38 .TP 20 | |
39 \fBSDL_GL_ACCUM_ALPHA_SIZE\fP | |
40 Size of the accumulation buffer alpha component, in bits | |
41 .SH "DESCRIPTION" | |
42 .PP | |
43 While you can set most OpenGL attributes normally, the attributes list above must be known \fIbefore\fP SDL sets the video mode\&. These attributes a set and read with \fI\fBSDL_GL_SetAttribute\fP\fR and \fI\fBSDL_GL_GetAttribute\fP\fR\&. | |
44 .SH "SEE ALSO" | |
45 .PP | |
46 \fI\fBSDL_GL_SetAttribute\fP\fR, \fI\fBSDL_GL_GetAttribute\fP\fR | |
181
e5bc29de3f0a
Updated from the SDL Documentation Project
Sam Lantinga <slouken@libsdl.org>
parents:
55
diff
changeset
|
47 ...\" created by instant / docbook-to-man, Tue 11 Sep 2001, 23:01 |