Mercurial > sdl-ios-xcode
view docs/html/sdlmixaudio.html @ 1018:012af0b7e8e6
Date: Fri, 24 Dec 2004 23:32:06 -0500
From: Mike Frysinger
Subject: [SDL] minor fix for gcc-2.x building
in src/video/directfb/SDL_DirectFB_video.c, some variables are not declared at
the beginning of scope ... newer gcc's will accept this, but gcc-2.x does not
find attached a simple patch by Matt Taylor to resolve this
http://bugs.gentoo.org/show_bug.cgi?id=75392
author | Sam Lantinga <slouken@libsdl.org> |
---|---|
date | Mon, 27 Dec 2004 20:03:53 +0000 |
parents | 355632dca928 |
children |
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<HTML ><HEAD ><TITLE >SDL_MixAudio</TITLE ><META NAME="GENERATOR" CONTENT="Modular DocBook HTML Stylesheet Version 1.76b+ "><LINK REL="HOME" TITLE="SDL Library Documentation" HREF="index.html"><LINK REL="UP" TITLE="Audio" HREF="audio.html"><LINK REL="PREVIOUS" TITLE="SDL_ConvertAudio" HREF="sdlconvertaudio.html"><LINK REL="NEXT" TITLE="SDL_LockAudio" HREF="sdllockaudio.html"></HEAD ><BODY CLASS="REFENTRY" BGCOLOR="#FFF8DC" TEXT="#000000" LINK="#0000ee" VLINK="#551a8b" ALINK="#ff0000" ><DIV CLASS="NAVHEADER" ><TABLE SUMMARY="Header navigation table" WIDTH="100%" BORDER="0" CELLPADDING="0" CELLSPACING="0" ><TR ><TH COLSPAN="3" ALIGN="center" >SDL Library Documentation</TH ></TR ><TR ><TD WIDTH="10%" ALIGN="left" VALIGN="bottom" ><A HREF="sdlconvertaudio.html" ACCESSKEY="P" >Prev</A ></TD ><TD WIDTH="80%" ALIGN="center" VALIGN="bottom" ></TD ><TD WIDTH="10%" ALIGN="right" VALIGN="bottom" ><A HREF="sdllockaudio.html" ACCESSKEY="N" >Next</A ></TD ></TR ></TABLE ><HR ALIGN="LEFT" WIDTH="100%"></DIV ><H1 ><A NAME="SDLMIXAUDIO" ></A >SDL_MixAudio</H1 ><DIV CLASS="REFNAMEDIV" ><A NAME="AEN7107" ></A ><H2 >Name</H2 >SDL_MixAudio -- Mix audio data</DIV ><DIV CLASS="REFSYNOPSISDIV" ><A NAME="AEN7110" ></A ><H2 >Synopsis</H2 ><DIV CLASS="FUNCSYNOPSIS" ><A NAME="AEN7111" ></A ><P ></P ><PRE CLASS="FUNCSYNOPSISINFO" >#include "SDL.h"</PRE ><P ><CODE ><CODE CLASS="FUNCDEF" >void <B CLASS="FSFUNC" >SDL_MixAudio</B ></CODE >(Uint8 *dst, Uint8 *src, Uint32 len, int volume);</CODE ></P ><P ></P ></DIV ></DIV ><DIV CLASS="REFSECT1" ><A NAME="AEN7117" ></A ><H2 >Description</H2 ><P >This function takes two audio buffers of <TT CLASS="PARAMETER" ><I >len</I ></TT > bytes each of the playing audio format and mixes them, performing addition, volume adjustment, and overflow clipping. The <TT CLASS="PARAMETER" ><I >volume</I ></TT > ranges from 0 to <TT CLASS="LITERAL" >SDL_MIX_MAXVOLUME</TT > 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.</P ><DIV CLASS="NOTE" ><BLOCKQUOTE CLASS="NOTE" ><P ><B >Note: </B >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.</P ></BLOCKQUOTE ></DIV ></DIV ><DIV CLASS="REFSECT1" ><A NAME="AEN7125" ></A ><H2 >See Also</H2 ><P ><A HREF="sdlopenaudio.html" ><TT CLASS="FUNCTION" >SDL_OpenAudio</TT ></A ></P ></DIV ><DIV CLASS="NAVFOOTER" ><HR ALIGN="LEFT" WIDTH="100%"><TABLE SUMMARY="Footer navigation table" WIDTH="100%" BORDER="0" CELLPADDING="0" CELLSPACING="0" ><TR ><TD WIDTH="33%" ALIGN="left" VALIGN="top" ><A HREF="sdlconvertaudio.html" ACCESSKEY="P" >Prev</A ></TD ><TD WIDTH="34%" ALIGN="center" VALIGN="top" ><A HREF="index.html" ACCESSKEY="H" >Home</A ></TD ><TD WIDTH="33%" ALIGN="right" VALIGN="top" ><A HREF="sdllockaudio.html" ACCESSKEY="N" >Next</A ></TD ></TR ><TR ><TD WIDTH="33%" ALIGN="left" VALIGN="top" >SDL_ConvertAudio</TD ><TD WIDTH="34%" ALIGN="center" VALIGN="top" ><A HREF="audio.html" ACCESSKEY="U" >Up</A ></TD ><TD WIDTH="33%" ALIGN="right" VALIGN="top" >SDL_LockAudio</TD ></TR ></TABLE ></DIV ></BODY ></HTML >