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_ConvertSurface" "3" "Tue 11 Sep 2001, 23:01" "SDL" "SDL API Reference" 
.SH "NAME"
SDL_ConvertSurface\- Converts a surface to the same format as another surface\&.
.SH "SYNOPSIS"
.PP
\fB#include "SDL/SDL\&.h"
.sp
\fBSDL_Surface *\fBSDL_ConvertSurface\fP\fR(\fBSDL_Surface *src, SDL_PixelFormat *fmt, Uint32 flags\fR);
.SH "DESCRIPTION"
.PP
Creates a new surface of the specified format, and then copies and maps the given surface to it\&. If this function fails, it returns \fBNULL\fP\&.
.PP
The \fBflags\fR parameter is passed to \fI\fBSDL_CreateRGBSurface\fP\fR and has those semantics\&.
.PP
This function is used internally by \fI\fBSDL_DisplayFormat\fP\fR\&.
.PP
This function can only be called after SDL_Init\&.
.SH "RETURN VALUE"
.PP
Returns either a pointer to the new surface, or \fBNULL\fP on error\&.
.SH "SEE ALSO"
.PP
\fI\fBSDL_CreateRGBSurface\fP\fR, \fI\fBSDL_DisplayFormat\fP\fR, \fI\fBSDL_PixelFormat\fR\fR, \fI\fBSDL_Surface\fR\fR
...\" created by instant / docbook-to-man, Tue 11 Sep 2001, 23:01