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;

.TH "SDL_CreateYUVOverlay" "3" "Tue 11 Sep 2001, 23:01" "SDL" "SDL API Reference" 
.SH "NAME"
SDL_CreateYUVOverlay\- Create a YUV video overlay
.SH "SYNOPSIS"
.PP
\fB#include "SDL\&.h"
.sp
\fBSDL_Overlay *\fBSDL_CreateYUVOverlay\fP\fR(\fBint width, int height, Uint32 format, SDL_Surface *display\fR);
.SH "DESCRIPTION"
.PP
\fBSDL_CreateYUVOverlay\fP creates a YUV overlay of the specified \fBwidth\fR, \fBheight\fR and \fBformat\fR (see \fI\fBSDL_Overlay\fR\fR for a list of available formats), for the provided \fBdisplay\fR\&. A \fI\fBSDL_Overlay\fR\fR structure is returned\&.
.PP
The term \&'overlay\&' is a misnomer since, unless the overlay is created in hardware, the contents for the display surface underneath the area where the overlay is shown will be overwritten when the overlay is displayed\&.
.SH "SEE ALSO"
.PP
\fI\fBSDL_Overlay\fR\fR, \fI\fBSDL_DisplayYUVOverlay\fP\fR, \fI\fBSDL_FreeYUVOverlay\fP\fR
...\" created by instant / docbook-to-man, Tue 11 Sep 2001, 23:01