Mercurial > sdl-ios-xcode
view docs/html/sdlmixaudio.html @ 1012:f14e3059e138
Date: Mon, 13 Dec 2004 21:28:18 -0500
From: Jonathan Atkins
Subject: [SDL] SDL_SaveBMP width bugfix
this fixes the pitch versus width difference that can happen
(especially for 8bit and 24bit (with the exact RGBAmasks) surfaces)
when you use SDL_SaveBMP. The problem was the pitch was used
instead of the width, which in some cases is much wider than the
screen area you really want to save...making for ugly crud on the
saved image borders.
This code has been tested with & without pitch overhangs...and
with the right masks for 24 bit surfaces.
I tested 8,15,16,24,32-0RGB,32-RGBA(with no SDL_SRCALPHA flag).
author | Sam Lantinga <slouken@libsdl.org> |
---|---|
date | Tue, 14 Dec 2004 06:20:49 +0000 |
parents | 355632dca928 |
children |
line wrap: on
line source
<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 >