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_BuildAudioCVT" "3" "Tue 11 Sep 2001, 22:58" "SDL" "SDL API Reference" 
.SH "NAME"
SDL_BuildAudioCVT\- Initializes a SDL_AudioCVT structure for conversion
.SH "SYNOPSIS"
.PP
\fB#include "SDL\&.h"
.sp
\fBint \fBSDL_BuildAudioCVT\fP\fR(\fBSDL_AudioCVT *cvt, Uint16 src_format, Uint8 src_channels, int src_rate, Uint16 dst_format, Uint8 dst_channels, int dst_rate\fR);
.SH "DESCRIPTION"
.PP
Before an \fI\fBSDL_AudioCVT\fR\fR structure can be used to convert audio data it must be initialized with source and destination information\&. 
.PP
\fBsrc_format\fR and \fBdst_format\fR are the source and destination format of the conversion\&. (For information on audio formats see \fI\fB SDL_AudioSpec\fR\fR)\&. \fBsrc_channels\fR and \fBdst_channels\fR are the number of channels in the source and destination formats\&. Finally, \fBsrc_rate\fR and \fBdst_rate\fR are the frequency or samples-per-second of the source and destination formats\&. Once again, see \fI\fBSDL_AudioSpec\fR\fR\&.
.SH "RETURN VALUES"
.PP
Returns \fB-1\fR if the filter could not be built or 1 if it could\&.
.SH "EXAMPLES"
.PP
See \fI\fBSDL_ConvertAudio\fP\fR\&.
.SH "SEE ALSO"
.PP
\fI\fBSDL_ConvertAudio\fP\fR, \fI\fBSDL_AudioCVT\fP\fR
...\" created by instant / docbook-to-man, Tue 11 Sep 2001, 22:58