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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><TITLE
>SDL_CDStatus</TITLE
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><H1
><A
NAME="SDLCDSTATUS"
></A
>SDL_CDStatus</H1
><DIV
CLASS="REFNAMEDIV"
><A
NAME="AEN7308"
></A
><H2
>Name</H2
>SDL_CDStatus&nbsp;--&nbsp;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 &#62; 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 &#62;= cdrom-&#62;numtracks) {
      track = cdrom-&#62;numtracks-1;
    }

    if ( SDL_CDPlayTracks(cdrom, track, 0, 1, 0) == 0 ) {
      playing = 1;
    }
  }
  return playing;
}</PRE
></DIV
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><A
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></A
><H2
>See Also</H2
><P
><A
HREF="sdlcd.html"
><TT
CLASS="FUNCTION"
>SDL_CD</TT
></A
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