Mercurial > sdl-ios-xcode
view docs/html/sdlwasinit.html @ 2042:3908e1f808e1
Fixed bug #292
I might be on crack here.
It looks like SDL_ConvertMono() in src/audio/SDL_audiocvt.c adds the left and
right channels of a stereo stream together, and clamps the new mono channel if
it would overflow.
Shouldn't it be dividing by 2 to average the two sample points instead of
clamping? Otherwise the mono sample point's volume doubles in the conversion.
This would also make the conversion faster, as it replaces two branches per
sample frame with a bitwise shift.
--ryan.
author | Sam Lantinga <slouken@libsdl.org> |
---|---|
date | Sun, 24 Sep 2006 15:56:36 +0000 |
parents | 355632dca928 |
children |
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<HTML ><HEAD ><TITLE >SDL_WasInit</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="General" HREF="general.html"><LINK REL="PREVIOUS" TITLE="SDL_Quit" HREF="sdlquit.html"><LINK REL="NEXT" TITLE="SDL_GetError" HREF="sdlgeterror.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="sdlquit.html" ACCESSKEY="P" >Prev</A ></TD ><TD WIDTH="80%" ALIGN="center" VALIGN="bottom" ></TD ><TD WIDTH="10%" ALIGN="right" VALIGN="bottom" ><A HREF="sdlgeterror.html" ACCESSKEY="N" >Next</A ></TD ></TR ></TABLE ><HR ALIGN="LEFT" WIDTH="100%"></DIV ><H1 ><A NAME="SDLWASINIT" ></A >SDL_WasInit</H1 ><DIV CLASS="REFNAMEDIV" ><A NAME="AEN617" ></A ><H2 >Name</H2 >SDL_WasInit -- Check which subsystems are initialized</DIV ><DIV CLASS="REFSYNOPSISDIV" ><A NAME="AEN620" ></A ><H2 >Synopsis</H2 ><DIV CLASS="FUNCSYNOPSIS" ><A NAME="AEN621" ></A ><P ></P ><PRE CLASS="FUNCSYNOPSISINFO" >#include "SDL.h"</PRE ><P ><CODE ><CODE CLASS="FUNCDEF" >Uint32 <B CLASS="FSFUNC" >SDL_WasInit</B ></CODE >(Uint32 flags);</CODE ></P ><P ></P ></DIV ></DIV ><DIV CLASS="REFSECT1" ><A NAME="AEN627" ></A ><H2 >Description</H2 ><P ><TT CLASS="FUNCTION" >SDL_WasInit</TT > allows you to see which SDL subsytems have been <A HREF="sdlinit.html" >initialized</A >. <TT CLASS="PARAMETER" ><I >flags</I ></TT > is a bitwise OR'd combination of the subsystems you wish to check (see <A HREF="sdlinit.html" ><TT CLASS="FUNCTION" >SDL_Init</TT ></A > for a list of subsystem flags).</P ></DIV ><DIV CLASS="REFSECT1" ><A NAME="AEN635" ></A ><H2 >Return Value</H2 ><P ><TT CLASS="FUNCTION" >SDL_WasInit</TT > returns a bitwised OR'd combination of the initialized subsystems.</P ></DIV ><DIV CLASS="REFSECT1" ><A NAME="AEN639" ></A ><H2 >Examples</H2 ><PRE CLASS="PROGRAMLISTING" > /* Here are several ways you can use SDL_WasInit() */ /* Get init data on all the subsystems */ Uint32 subsystem_init; subsystem_init=SDL_WasInit(SDL_INIT_EVERYTHING); if(subsystem_init&SDL_INIT_VIDEO) printf("Video is initialized.\n"); else printf("Video is not initialized.\n"); /* Just check for one specfic subsystem */ if(SDL_WasInit(SDL_INIT_VIDEO)!=0) printf("Video is initialized.\n"); else printf("Video is not initialized.\n"); /* Check for two subsystems */ Uint32 subsystem_mask=SDL_INIT_VIDEO|SDL_INIT_AUDIO; if(SDL_WasInit(subsystem_mask)==subsystem_mask) printf("Video and Audio initialized.\n"); else printf("Video and Audio not initialized.\n"); </PRE ></DIV ><DIV CLASS="REFSECT1" ><A NAME="AEN642" ></A ><H2 >See Also</H2 ><P ><A HREF="sdlinit.html" ><TT CLASS="FUNCTION" >SDL_Init</TT ></A >, <A HREF="sdlinitsubsystem.html" ><TT CLASS="FUNCTION" >SDL_Subsystem</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="sdlquit.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="sdlgeterror.html" ACCESSKEY="N" >Next</A ></TD ></TR ><TR ><TD WIDTH="33%" ALIGN="left" VALIGN="top" >SDL_Quit</TD ><TD WIDTH="34%" ALIGN="center" VALIGN="top" ><A HREF="general.html" ACCESSKEY="U" >Up</A ></TD ><TD WIDTH="33%" ALIGN="right" VALIGN="top" >SDL_GetError</TD ></TR ></TABLE ></DIV ></BODY ></HTML >