view docs/man3/SDL_MixAudio.3 @ 4223:63fd67e17705 SDL-1.2

Fixed bug #727 Lorenzo Desole 2009-04-19 07:36:10 PDT I am one of the developers of a multimedia application (My Media System MMS), which uses SDL. MMS is normally running in fullscreen mode but it switches it off before launching external applications (mplayer, xine, etc.). The problem with fullscreen is that when the latter is switched off either via SDL_WM_ToggleFullScreen() or SDL_SetVideoMode(), SDL compares the current screen sizes with the ones saved when the video system was initted, and if they don't match, it calls XF86VidModeSwitchToMode() to switch to the old modeline. This makes it impossible for external programs and for MMS itself to use RandR to change the screen size, because next time fullscreen mode is turned off, it bombs out with the following error: X Error of failed request: BadValue (integer parameter out of range for operation) Major opcode of failed request: 136 (XFree86-VidModeExtension) Minor opcode of failed request: 10 (XF86VidModeSwitchToMode) [...] Obviously this happens only if the new screen resolution is smaller than the original one and XF86VidModeSwitchToMode() can't succeed. I couldn't find any way to inform SDL that the screen resolution it uses as reference is no longer valid. This can be fixed by adding "save_mode(this)" to ./src/video/x11/SDL_x11modes.c, API X11_EnterFullScreen(_THIS), like this: int X11_EnterFullScreen(_THIS) { int okay; + save_mode(this); I can't rule out possible side effects, but I don't see any. While I admit this is a minor issue for the general users, it is a major showstopper for our program where the ability to change screen resolution and refresh rate according to the movie being played, is very important. Thanks in advance.
author Sam Lantinga <slouken@libsdl.org>
date Mon, 21 Sep 2009 11:14:36 +0000
parents 4e3b250c950e
children 1238da4a7112
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.TH "SDL_MixAudio" "3" "Tue 11 Sep 2001, 22:58" "SDL" "SDL API Reference" 
.SH "NAME"
SDL_MixAudio \- Mix audio data
.SH "SYNOPSIS"
.PP
\fB#include "SDL\&.h"
.sp
\fBvoid \fBSDL_MixAudio\fP\fR(\fBUint8 *dst, Uint8 *src, Uint32 len, int volume\fR);
.SH "DESCRIPTION"
.PP
This function takes two audio buffers of \fBlen\fR bytes each of the playing audio format and mixes them, performing addition, volume adjustment, and overflow clipping\&. The \fBvolume\fR ranges from 0 to \fBSDL_MIX_MAXVOLUME\fP and should be set to the maximum value for full audio volume\&. Note this does not change hardware volume\&. This is provided for convenience -- you can mix your own audio data\&.
.PP
.RS
\fBNote:  
.PP
Do not use this function for mixing together more than two streams of sample data\&. The output from repeated application of this function may be distorted by clipping, because there is no accumulator with greater range than the input (not to mention this being an inefficient way of doing it)\&. Use mixing functions from SDL_mixer, OpenAL, or write your own mixer instead\&.
.RE
.SH "SEE ALSO"
.PP
\fI\fBSDL_OpenAudio\fP\fR
...\" created by instant / docbook-to-man, Tue 11 Sep 2001, 22:58