Mercurial > sdl-ios-xcode
annotate docs/man3/SDL_VideoInfo.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
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1 .TH "SDL_VideoInfo" "3" "Tue 11 Sep 2001, 23:01" "SDL" "SDL API Reference" |
0 | 2 .SH "NAME" |
3 SDL_VideoInfo\- Video Target information | |
4 .SH "STRUCTURE DEFINITION" | |
5 .PP | |
6 .nf | |
7 \f(CWtypedef struct{ | |
8 Uint32 hw_available:1; | |
9 Uint32 wm_available:1; | |
10 Uint32 blit_hw:1; | |
11 Uint32 blit_hw_CC:1; | |
12 Uint32 blit_hw_A:1; | |
13 Uint32 blit_sw:1; | |
14 Uint32 blit_sw_CC:1; | |
15 Uint32 blit_sw_A:1; | |
16 Uint32 blit_fill; | |
17 Uint32 video_mem; | |
18 SDL_PixelFormat *vfmt; | |
19 } SDL_VideoInfo;\fR | |
20 .fi | |
21 .PP | |
22 .SH "STRUCTURE DATA" | |
23 .TP 20 | |
24 \fBhw_available\fR | |
25 Is it possible to create hardware surfaces? | |
26 .TP 20 | |
27 \fBwm_available\fR | |
28 Is there a window manager available | |
29 .TP 20 | |
30 \fBblit_hw\fR | |
31 Are hardware to hardware blits accelerated? | |
32 .TP 20 | |
33 \fBblit_hw_CC\fR | |
34 Are hardware to hardware colorkey blits accelerated? | |
35 .TP 20 | |
36 \fBblit_hw_A\fR | |
37 Are hardware to hardware alpha blits accelerated? | |
38 .TP 20 | |
39 \fBblit_sw\fR | |
40 Are software to hardware blits accelerated? | |
41 .TP 20 | |
42 \fBblit_sw_CC\fR | |
43 Are software to hardware colorkey blits accelerated? | |
44 .TP 20 | |
45 \fBblit_sw_A\fR | |
46 Are software to hardware alpha blits accelerated? | |
47 .TP 20 | |
48 \fBblit_fill\fR | |
49 Are color fills accelerated? | |
50 .TP 20 | |
51 \fBvideo_mem\fR | |
52 Total amount of video memory in Kilobytes | |
53 .TP 20 | |
54 \fBvfmt\fR | |
55 \fIPixel format\fR of the video device | |
56 .SH "DESCRIPTION" | |
57 .PP | |
58 This (read-only) structure is returned by \fI\fBSDL_GetVideoInfo\fP\fR\&. It contains information on either the \&'best\&' available mode (if called before \fI\fBSDL_SetVideoMode\fP\fR) or the current video mode\&. | |
59 .SH "SEE ALSO" | |
60 .PP | |
61 \fI\fBSDL_PixelFormat\fR\fR, \fI\fBSDL_GetVideoInfo\fP\fR | |
181
e5bc29de3f0a
Updated from the SDL Documentation Project
Sam Lantinga <slouken@libsdl.org>
parents:
55
diff
changeset
|
62 ...\" created by instant / docbook-to-man, Tue 11 Sep 2001, 23:01 |