SDL::Mixer::Effects -- SDL_Mixer sound effect functions and bindings
+SDL::Mixer::Effects - sound effect functions
Mixer
-Note: >= 1.2.10
+SDL::Mixer::Effects::register( $channel, $effect_callback, $done_callback, $arg ); + ++
Hook a processor function into a channel for post processing effects. You may just be reading the data and displaying it, or you may be altering
+the stream to add an echo. Most processors also have state data that they allocate as they are in use, this would be stored in the $arg data
+space. When a processor is finished being used, any function passed into $done_callback will be called.
The effects are put into a linked list, and always appended to the end, meaning they always work on previously registered effects output.
+Returns: Zero on errors, such as a nonexisting channel.
+Note: Passing MIX_CHANNEL_POST will register the $effect_callback as an postmix effect.
Note: Do not use this on a threaded perl. This will crash.
+Example:
+ use SDL;
+ use SDL::Mixer;
+ use SDL::Mixer::Channels;
+ use SDL::Mixer::Effects;
+ use SDL::Mixer::Samples;
+
+ my @last_stream = ();
+ my $echo_effect_func = sub
+ {
+ my $channel = shift;
+ my $samples = shift;
+ my $position = shift;
+ my @stream = @_;
+
+ my @stream2 = @stream;
+ my $offset = $samples / 2;
+ for(my $i = 0; $i < $samples; $i+=2)
+ {
+ if($i < $offset)
+ {
+ if(scalar(@last_stream) == $samples)
+ {
+ $stream2[$i] = $stream[$i] * 0.6 + $last_stream[$samples + $i - $offset] * 0.4; # left
+ $stream2[$i + 1] = $stream[$i + 1] * 0.6 + $last_stream[$samples + $i - $offset + 1] * 0.4; # right
+ }
+ }
+ else
+ {
+ $stream2[$i] = $stream[$i] * 0.6 + $stream[$i - $offset] * 0.4; # left
+ $stream2[$i + 1] = $stream[$i + 1] * 0.6 + $stream[$i - $offset + 1] * 0.4; # right
+ }
+ }
+
+ @last_stream = @stream;
+ return @stream2;
+ };
+
+ my $effect_done = sub
+ {
+ # you may do something here
+ };
+
+ SDL::Mixer::open_audio( 44100, SDL::Constants::AUDIO_S16, 2, 1024 );
+
+ my $playing_channel = SDL::Mixer::Channels::play_channel( -1, SDL::Mixer::Samples::load_WAV('test/data/sample.wav'), -1 );
+ SDL::Mixer::Effects::register($playing_channel, $echo_effect_func, $effect_done, 0);
+ SDL::delay(2000);
+ SDL::Mixer::Effects::unregister($playing_channel, $echo_effect_func);
+
+ SDL::Mixer::close_audio();
+ SDL::quit();
+
+
+
+SDL::Mixer::Effects::unregister( $channel, $effect_callback ); + ++
Remove the registered effect function from the effect list for channel.
+If the channel is active the registered effect will have its $done_callback function called, if it was specified in
+SDL::Mixer::Effects::register.
Returns: Zero on errors, such as invalid channel, or effect function not registered on channel.
+Note: Do not use this on a threaded perl. This will crash.
+ +SDL::Mixer::Effects::unregister_all( $channel ); + ++
This removes all effects registered to $channel. If the channel is active all the registered effects will have their $done_callback
+functions called, if they were specified in SDL::Mixer::Effects::register.
Returns: Zero on errors, such as channel not existing.
+Note: Do not use this on a threaded perl. This will crash.
SDL::Mixer::Effects::set_post_mix( $effect_callback, $arg ); + ++
Hook a processor function to the postmix stream for post processing effects. You may just be reading the data and displaying it, or you may be +altering the stream to add an echo. This processor is never really finished, until you call it without arguments. +There can only be one postmix function used at a time through this method. Use SDL::Mixer::Effects::register with MIX_CHANNEL_POST to use multiple postmix processors. +This postmix processor is run AFTER all the registered postmixers set up by SDL::Mixer::Effects::register.
+Note: Do not use this on a threaded perl. This will crash.
+ +SDL::Mixer::Effects::set_distance( $channel, $distance ); + ++
This effect simulates a simple attenuation of volume due to distance. The volume never quite reaches silence, even at max distance (255).
NOTE: Using a distance of 0 will cause the effect to unregister itself from channel. You cannot unregister it any other way, unless you use
+SDL::Mixer::Effects::unregister_all on the channel.
Returns: Zero on errors, such as an invalid channel, or if Mix_RegisterEffect failed.
SDL::Mixer::Effects::set_panning( $channel, $left, $right ); + ++
This effect will only work on stereo audio. Meaning you called SDL::Mixer::open_audio with 2 channels.
+Note: Setting both left and right to 255 will unregister the effect from channel. You cannot unregister it any other way, unless you use +SDL::Mixer::Effects::unregister_all on the channel.
+Note: Using this function on a mono audio device will not register the effect, nor will it return an error status.
+Returns: Zero on errors, such as bad channel, or if SDL::Mixer::Effects::register failed.
+ +SDL::Mixer::Effects::set_position( $channel, $angle, $distance ); + ++
This effect emulates a simple 3D audio effect. It's not all that realistic, but it can help improve some level of realism. By giving it the +angle and distance from the camera's point of view, the effect pans and attenuates volumes.
+$angle is the direction in relation to forward from 0 to 360 degrees. Larger angles will be reduced to this range using angles % 360.
So you can see it goes clockwise starting at directly in front.
+$distance is 0(close/loud) to 255(far/quiet).
Note: Using angle and distance of 0, will cause the effect to unregister itself from channel. You cannot unregister it any other way,
+unless you use SDL::Mixer::Effects::unregister_all on the channel.
Returns: Zero on errors, such as an invalid channel, or if SDL::Mixer::Effects::register failed.
SDL::Mixer::Effects::set_reverse_stereo( $channel, $flip ); + ++
If you pass 1 to $flip it simple reverse stereo, swaps left and right channel sound.
Note: Using a flip of 0, will cause the effect to unregister itself from channel. You cannot unregister it any other way, unless you use
+SDL::Mixer::Effects::register on the channel.
See AUTHORS in SDL.