Mercurial > sdl-ios-xcode
view docs/html/sdlcdstatus.html @ 3880:74e828c64315 SDL-1.2
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 15:45:37 +0000 |
parents | 355632dca928 |
children |
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<HTML ><HEAD ><TITLE >SDL_CDStatus</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="CD-ROM" HREF="cdrom.html"><LINK REL="PREVIOUS" TITLE="SDL_CDOpen" HREF="sdlcdopen.html"><LINK REL="NEXT" TITLE="SDL_CDPlay" HREF="sdlcdplay.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="sdlcdopen.html" ACCESSKEY="P" >Prev</A ></TD ><TD WIDTH="80%" ALIGN="center" VALIGN="bottom" ></TD ><TD WIDTH="10%" ALIGN="right" VALIGN="bottom" ><A HREF="sdlcdplay.html" ACCESSKEY="N" >Next</A ></TD ></TR ></TABLE ><HR ALIGN="LEFT" WIDTH="100%"></DIV ><H1 ><A NAME="SDLCDSTATUS" ></A >SDL_CDStatus</H1 ><DIV CLASS="REFNAMEDIV" ><A NAME="AEN7308" ></A ><H2 >Name</H2 >SDL_CDStatus -- Returns the current status of the given drive.</DIV ><DIV CLASS="REFSYNOPSISDIV" ><A NAME="AEN7311" ></A ><H2 >Synopsis</H2 ><DIV CLASS="FUNCSYNOPSIS" ><A NAME="AEN7312" ></A ><P ></P ><PRE CLASS="FUNCSYNOPSISINFO" >#include "SDL.h"</PRE ><P ><CODE ><CODE CLASS="FUNCDEF" >CDstatus <B CLASS="FSFUNC" >SDL_CDStatus</B ></CODE >(SDL_CD *cdrom);</CODE ></P ><PRE CLASS="FUNCSYNOPSISINFO" >/* Given a status, returns true if there's a disk in the drive */ #define CD_INDRIVE(status) ((int)status > 0)</PRE ><P ></P ></DIV ></DIV ><DIV CLASS="REFSECT1" ><A NAME="AEN7319" ></A ><H2 >Description</H2 ><P >This function returns the current status of the given drive. Status is described like so: <PRE CLASS="PROGRAMLISTING" >typedef enum { CD_TRAYEMPTY, CD_STOPPED, CD_PLAYING, CD_PAUSED, CD_ERROR = -1 } CDstatus;</PRE ></P ><P >If the drive has a CD in it, the table of contents of the CD and current play position of the CD will be stored in the SDL_CD structure.</P ><P >The macro <TT CLASS="LITERAL" >CD_INDRIVE</TT > is provided for convenience, and given a status returns true if there's a disk in the drive.</P ><DIV CLASS="NOTE" ><BLOCKQUOTE CLASS="NOTE" ><P ><B >Note: </B ><TT CLASS="FUNCTION" >SDL_CDStatus</TT > also updates the <A HREF="sdlcd.html" ><SPAN CLASS="STRUCTNAME" >SDL_CD</SPAN ></A > structure passed to it.</P ></BLOCKQUOTE ></DIV ></DIV ><DIV CLASS="REFSECT1" ><A NAME="AEN7331" ></A ><H2 >Example</H2 ><PRE CLASS="PROGRAMLISTING" >int playTrack(int track) { int playing = 0; if ( CD_INDRIVE(SDL_CDStatus(cdrom)) ) { /* clamp to the actual number of tracks on the CD */ if (track >= cdrom->numtracks) { track = cdrom->numtracks-1; } if ( SDL_CDPlayTracks(cdrom, track, 0, 1, 0) == 0 ) { playing = 1; } } return playing; }</PRE ></DIV ><DIV CLASS="REFSECT1" ><A NAME="AEN7334" ></A ><H2 >See Also</H2 ><P ><A HREF="sdlcd.html" ><TT CLASS="FUNCTION" >SDL_CD</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="sdlcdopen.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="sdlcdplay.html" ACCESSKEY="N" >Next</A ></TD ></TR ><TR ><TD WIDTH="33%" ALIGN="left" VALIGN="top" >SDL_CDOpen</TD ><TD WIDTH="34%" ALIGN="center" VALIGN="top" ><A HREF="cdrom.html" ACCESSKEY="U" >Up</A ></TD ><TD WIDTH="33%" ALIGN="right" VALIGN="top" >SDL_CDPlay</TD ></TR ></TABLE ></DIV ></BODY ></HTML >