view docs/html/guidecdromexamples.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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>CDROM Examples</H1
><P
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><DIV
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><H2
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><A
NAME="AEN393"
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>Listing CD-ROM drives</H2
><P
><PRE
CLASS="PROGRAMLISTING"
>    #include "SDL.h"

    /* Initialize SDL first */
    if ( SDL_Init(SDL_INIT_CDROM) &#60; 0 ) {
        fprintf(stderr, "Couldn't initialize SDL: %s\n",SDL_GetError());
        exit(1);
    }
    atexit(SDL_Quit);

    /* Find out how many CD-ROM drives are connected to the system */
    printf("Drives available: %d\n", SDL_CDNumDrives());
    for ( i=0; i&#60;SDL_CDNumDrives(); ++i ) {
        printf("Drive %d:  \"%s\"\n", i, SDL_CDName(i));
    }</PRE
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><DIV
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><H2
CLASS="SECT2"
><A
NAME="AEN397"
></A
>Opening the default drive</H2
><P
><PRE
CLASS="PROGRAMLISTING"
>    SDL_CD *cdrom;
    CDstatus status;
    char *status_str;

    cdrom = SDL_CDOpen(0);
    if ( cdrom == NULL ) {
        fprintf(stderr, "Couldn't open default CD-ROM drive: %s\n",
                        SDL_GetError());
        exit(2);
    }

    status = SDL_CDStatus(cdrom);
    switch (status) {
        case CD_TRAYEMPTY:
            status_str = "tray empty";
            break;
        case CD_STOPPED:
            status_str = "stopped";
            break;
        case CD_PLAYING:
            status_str = "playing";
            break;
        case CD_PAUSED:
            status_str = "paused";
            break;
        case CD_ERROR:
            status_str = "error state";
            break;
    }
    printf("Drive status: %s\n", status_str);
    if ( status &#62;= CD_PLAYING ) {
        int m, s, f;
        FRAMES_TO_MSF(cdrom-&#62;cur_frame, &#38;m, &#38;s, &#38;f);
        printf("Currently playing track %d, %d:%2.2d\n",
        cdrom-&#62;track[cdrom-&#62;cur_track].id, m, s);
    }</PRE
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><H2
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><A
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></A
>Listing the tracks on a CD</H2
><P
><PRE
CLASS="PROGRAMLISTING"
>    SDL_CD *cdrom;          /* Assuming this has already been set.. */
    int i;
    int m, s, f;

    SDL_CDStatus(cdrom);
    printf("Drive tracks: %d\n", cdrom-&#62;numtracks);
    for ( i=0; i&#60;cdrom-&#62;numtracks; ++i ) {
        FRAMES_TO_MSF(cdrom-&#62;track[i].length, &#38;m, &#38;s, &#38;f);
        if ( f &#62; 0 )
            ++s;
        printf("\tTrack (index %d) %d: %d:%2.2d\n", i,
        cdrom-&#62;track[i].id, m, s);
    }</PRE
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>Play an entire CD</H2
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><PRE
CLASS="PROGRAMLISTING"
>    SDL_CD *cdrom;          /* Assuming this has already been set.. */

    // Play entire CD:
    if ( CD_INDRIVE(SDL_CDStatus(cdrom)) )
        SDL_CDPlayTracks(cdrom, 0, 0, 0, 0);

        // Play last track:
        if ( CD_INDRIVE(SDL_CDStatus(cdrom)) ) {
            SDL_CDPlayTracks(cdrom, cdrom-&#62;numtracks-1, 0, 0, 0);
        }

        // Play first and second track and 10 seconds of third track:
        if ( CD_INDRIVE(SDL_CDStatus(cdrom)) )
            SDL_CDPlayTracks(cdrom, 0, 0, 2, CD_FPS * 10);</PRE
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