view 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
line wrap: on
line source

.TH "SDL_VideoInfo" "3" "Tue 11 Sep 2001, 23:01" "SDL" "SDL API Reference" 
.SH "NAME"
SDL_VideoInfo\- Video Target information
.SH "STRUCTURE DEFINITION"
.PP
.nf
\f(CWtypedef struct{
  Uint32 hw_available:1;
  Uint32 wm_available:1;
  Uint32 blit_hw:1;
  Uint32 blit_hw_CC:1;
  Uint32 blit_hw_A:1;
  Uint32 blit_sw:1;
  Uint32 blit_sw_CC:1;
  Uint32 blit_sw_A:1;
  Uint32 blit_fill;
  Uint32 video_mem;
  SDL_PixelFormat *vfmt;
} SDL_VideoInfo;\fR
.fi
.PP
.SH "STRUCTURE DATA"
.TP 20
\fBhw_available\fR
Is it possible to create hardware surfaces?
.TP 20
\fBwm_available\fR
Is there a window manager available
.TP 20
\fBblit_hw\fR
Are hardware to hardware blits accelerated?
.TP 20
\fBblit_hw_CC\fR
Are hardware to hardware colorkey blits accelerated?
.TP 20
\fBblit_hw_A\fR
Are hardware to hardware alpha blits accelerated?
.TP 20
\fBblit_sw\fR
Are software to hardware blits accelerated?
.TP 20
\fBblit_sw_CC\fR
Are software to hardware colorkey blits accelerated?
.TP 20
\fBblit_sw_A\fR
Are software to hardware alpha blits accelerated?
.TP 20
\fBblit_fill\fR
Are color fills accelerated?
.TP 20
\fBvideo_mem\fR
Total amount of video memory in Kilobytes
.TP 20
\fBvfmt\fR
\fIPixel format\fR of the video device
.SH "DESCRIPTION"
.PP
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\&.
.SH "SEE ALSO"
.PP
\fI\fBSDL_PixelFormat\fR\fR, \fI\fBSDL_GetVideoInfo\fP\fR
...\" created by instant / docbook-to-man, Tue 11 Sep 2001, 23:01