SDL::Mixer::Music

Section: User Contributed Perl Documentation (3)
Updated: 2020-07-28
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NAME

SDL::Mixer::Music - functions for music  

CATEGORY

Mixer  

METHODS

 

load_MUS

 my $music = SDL::Mixer::Music::load_MUS( $file );

"load_MUS" loads a music file into a "SDL::Mixer::MixMusic" structure. This can be passed to play_music.  

load_MUS_RW

 my $music = SDL::Mixer::Music::load_MUS_RW( $rwops );

"load_MUS_RW" does the same like "load_MUS" except that it accepts an SDL::RWOps-object rather than a filename.

Example for loading music from a variable:

 use SDL;
 use SDL::Mixer;
 use SDL::Mixer::Music;
 use SDL::RWOps;
 
 [...]
 
 my $rwops = SDL::RWOps->new_const_mem( $scalar_holding_music );
 my $music = SDL::Mixer::Music::load_MUS_RW( $rwops );

Note: You need at least libSDL_mixer 1.2.7 for this feature.  

hook_music

 SDL::Mixer::Music::hook_music( $callback, $position );

This sets up a custom music player function, so you can pass your own audio stream data into the SDL::Mixer. The function will be called with "position" passed into the first parameter when the "callback" is called. The audio stream buffer has to be filled with length bytes of music (2nd parameter). The music player will then be called automatically when the mixer needs it. Music playing will start as soon as this is called. All the music playing and stopping functions have no effect on music after this. Pause and resume will work. Using a custom music player and the internal music player is not possible, the custom music player takes priority.

To stop the custom music player call "hook_music()" without arguments.

Note: NEVER call "SDL::Mixer" functions, nor SDL::Audio::lock, from a callback function.

Note: At program termination also call "SDL::Mixer::Music::hook_music()" to stop this callback.

Example:

 sub callback
 {
     my $position = shift; # position (first time its 0, on each call $length is added)
     my $length   = shift; # length of bytes we have to put in stream
     my @stream   = '';
 
     printf("position=%8d, stream length=%6d\n", $position, $length);
 
     for(my $i = 0; $i < $length; $i++)
     {
         push(@stream, (($i + $position) & 0xFF));
     }
 
     return @stream;
 }
 
 SDL::Mixer::Music::hook_music( 'main::callback', 0 );

 

hook_music_finished

 SDL::Mixer::Music::hook_music_finished( 'main::callback' );

This callback is called when music called by e.g. SDL::Mixer::Music::play_music or SDL::Mixer::Music::fade_in_music stops naturally. This happens when the music is over or is fading out.

Note: If you play music via SDL::Mixer::Music::hook_music, this callback will never be called.

Example:

 my $music_is_playing = 0;
 my @music            = qw(first.mp3 next.mp3 other.mp3 last.mp3);
 sub callback
 {
     $music_is_playing = 0;
 }
 
 SDL::Mixer::Music::hook_music_finished( 'main::callback' );
 
 foreach my $this_song ( @music )
 {
     SDL::Mixer::Music::play_music( $this_song, 0 );
     $music_is_playing = 1;
 
     SDL::delay( 100 ) while( $music_is_playing );
 }
 
 SDL::Mixer::Music::hook_music_finished(); # cleanup

 

get_music_hook_data

 my $position = SDL::Mixer::Music::get_music_hook_data();

Returns the "position" (first) parameter that will be passed to SDL::Mixer::Music::hook_music's callback.  

play_music

 my $play_music = SDL::Mixer::Music::play_music( $mix_music, $loops );

"play_music" plays a given "SDL::Mixer::MixMusic". Passing -1 to $loops will loop the music infinitely.

Example:

 my $music = SDL::Mixer::Music::load_MUS( 'music.mp3' );
 
 unless(SDL::Mixer::Music::play_music($sample_music, -1))
 {
     print("Something went wrong!\n");
 }

 

fade_in_music

 my $music = SDL::Mixer::Music::fade_in_music( $mix_music, $loops, $ms );

Same as SDL::Mixer::Music::play_music but you can specify the fade-in time by $ms.  

fade_out_music

 my $fading_music = SDL::Mixer::Music::fade_out_music( $ms );

"fade_out_music" fades out the music with a duration specified in "ms" in milliseconds.

Returns the the number of channels that will be faded out.  

fading_music

 my $fading_music = SDL::Mixer::Music::fading_music();

Returns one of the following:

MIX_NO_FADING
MIX_FADING_OUT
MIX_FADING_IN
 

volume_music

 my $volume_before = SDL::Mixer::Music::volume_music( $new_volume );

"volume_music" set the volume in $new_volume and returns the volume that was set before. Passing "-1" as argument causes only to return the current volume.

Volume is between 0 (silence) and "MIX_MAX_VOLUME = 128".

Example:

 # set the music volume to 1/2 maximum, and then check it
 printf( "volume was    : %d\n", SDL::Mixer::Music::volume_music( MIX_MAX_VOLUME / 2 ) );
 printf( "volume is now : %d\n", SDL::Mixer::Music::volume_music( -1 ) );

 

halt_music

 SDL::Mixer::Music::halt_music();

Halts the music.  

pause_music

 SDL::Mixer::Music::pause_music();

Pauses the music.  

resume_music

 SDL::Mixer::Music::resume_music();

Resumes the music.  

rewind_music

 SDL::Mixer::Music::rewind_music();

Rewinds the music.  

set_music_position

 SDL::Mixer::Music::set_music_position( $position );

Set the position of the currently playing music. The position takes different meanings for different music sources. It only works on the music sources listed below.

MOD
The double is cast to Uint16 and used for a pattern number in the module. Passing zero is similar to rewinding the song.
OGG
Jumps to position seconds from the beginning of the song.
MP3
Jumps to position seconds from the current position in the stream. So you may want to call SDL::Mixer::Music::rewind_music before this. Does not go in reverse... negative values do nothing.

Returns: 0 on success, or "-1" if the codec doesn't support this function.  

paused_music

 my $paused = SDL::Mixer::Music::paused_music();

Returns 1 if the music is paused, otherwise 0.  

playing_music

 my $playing_music = SDL::Mixer::Music::playing_music();

Returns 1 if the music is playing sound, otherwise 0. It doesn't check if the music is paused.  

AUTHORS

See ``AUTHORS'' in SDL.


 

Index

NAME
CATEGORY
METHODS
load_MUS
load_MUS_RW
hook_music
hook_music_finished
get_music_hook_data
play_music
fade_in_music
fade_out_music
fading_music
volume_music
halt_music
pause_music
resume_music
rewind_music
set_music_position
paused_music
playing_music
AUTHORS