sound

Checks if background music is playing, e.g. from iTunes. On non mobile platforms, this function always return false. On Android you can only get a correct reading of this state if your game is not playing any sounds itself. This is a limitation in the Android SDK. If your game is playing any sounds, even with a gain of zero, this function will return false. The best time to call this function is:

• In the init function of your main collection script before any sounds are triggered

• In a window listener callback when the window.WINDOW_EVENT_FOCUS_GAINED event is received

Both those times will give you a correct reading of the state even when your application is swapped out and in while playing sounds and it works equally well on Android and iOS.

// If music is playing, mute "master":
if (sound.is_music_playing()) {
  // mute "master"
  sound.set_group_gain("master", 0);
}

Returns

• playing: boolean — true if music is playing, otherwise false.

Get RMS (Root Mean Square) value from mixer group. This value is the square root of the mean (average) value of the squared function of the instantaneous values. For instance: for a sinewave signal with a peak gain of -1.94 dB (0.8 linear), the RMS is 0.8 × 1/sqrt(2) which is about 0.566. Note the returned value might be an approximation and in particular the effective window might be larger than specified.

// Get the RMS from the "master" group where a mono -1.94 dB sinewave is playing:
const [rms] = sound.get_rms("master", 0.1); // throw away right channel.
print(rms); // => 0.56555819511414

Parameters

• group: string | Hash — group name
• window: number — window length in seconds

Returns

• rms_l: number — RMS value for left channel
• rms_r: number — RMS value for right channel

Get peak value from mixer group. Note that gain is in linear scale, between 0 and 1. To get the dB value from the gain, use the formula 20 * log(gain). Inversely, to find the linear value from a dB value, use the formula 10db/20. Also note that the returned value might be an approximation and in particular the effective window might be larger than specified.

// Get the peak gain from the "master" group and convert to dB for displaying:
const [left_p, right_p] = sound.get_peak("master", 0.1);
const left_p_db = 20 * Math.log(left_p);
const right_p_db = 20 * Math.log(right_p);

Parameters

• group: string | Hash — group name
• window: number — window length in seconds

Returns

• peak_l: number — peak value for left channel
• peak_r: number — peak value for right channel

Set mixer group gain

// Set mixer group gain on the "soundfx" group to 50% (-30dB):
sound.set_group_gain("soundfx", 0.5);

Parameters

• group: string | Hash — group name
• gain: number — gain in range [0..1] mapped to [0 .. -60dB]

Get mixer group gain

// Get the mixer group gain for the "soundfx" and convert to dB:
const gain = sound.get_group_gain("soundfx");
const gain_db = 60 * gain;

Parameters

• group: string | Hash — group name

Returns

• gain: number — gain in [0 1] range ([-60dB.. 0dB])

Get a table of all mixer group names (hashes).

// Get the mixer groups, set all gains to 0 except for "master" and "soundfx"
// where gain is set to 1:
const groups = sound.get_groups();
for (const group of groups) {
  if (group === hash("master") || group === hash("soundfx")) {
    sound.set_group_gain(group, 1);
  } else {
    sound.set_group_gain(group, 0);
  }
}

Returns

• groups: Record<string | number, unknown> — table of mixer group names

Get a mixer group name as a string. This function is to be used for debugging and development tooling only. The function does a reverse hash lookup, which does not return a proper string value when the game is built in release mode.

// Get the mixer group string names so we can show them as labels on a dev mixer overlay:
const groups = sound.get_groups();
for (const group of groups) {
  const name = sound.get_group_name(group);
  msg.post("/mixer_overlay#gui", "set_mixer_label", { group: group, label: name });
}

Parameters

• group: string | Hash — group name

Returns

• name: string — group name

Checks if a phone call is active. If there is an active phone call all other sounds will be muted until the phone call is finished. On non mobile platforms, this function always return false.

// Test if a phone call is on-going:
if (sound.is_phone_call_active()) {
  // do something sensible.
}

Returns

• call_active: boolean — true if there is an active phone call, false otherwise.

Make the sound component play its sound. Multiple voices are supported. The limit is set to 32 voices per sound component. A sound will continue to play even if the game object the sound component belonged to is deleted. You can call sound.stop() to stop the sound.

// Assuming the script belongs to an instance with a sound-component with id
// "sound", this will make the component play its sound after 1 second:
sound.play("#sound", { delay: 1, gain: 0.9, pan: -1.0 });

// Using the callback argument, you can chain several sounds together:
function sound_done(self, message_id, message, sender) {
  // play 'boom' sound fx when the countdown has completed
  if (message_id === hash("sound_done") && message.play_id === self.countdown_id) {
    sound.play("#boom", undefined, sound_done);
  }
}

export default defineScript({
  init(self) {
    self.countdown_id = sound.play("#countdown", undefined, sound_done);
  },
});

Parameters

• url: string | Hash | Url — the sound that should play
• play_properties?: Record<string | number, unknown> — optional table with properties: delay number delay in seconds before the sound starts playing, default is 0. gain number sound gain between 0 and 1, default is 1. The final gain of the sound will be a combination of this gain, the group gain and the master gain. pan number sound pan between -1 and 1, default is 0. The final pan of the sound will be an addition of this pan and the sound pan. speed number sound speed where 1.0 is normal speed, 0.5 is half speed and 2.0 is double speed. Valid range is 0.0 to 50.0. The final speed of the sound will be a multiplication of this speed and the sound speed. start_time number start playback offset (seconds). Optional, mutually exclusive with start_frame. start_frame number start playback offset (frames/samples). Optional, mutually exclusive with start_time. If both are provided, start_frame is used.
• complete_function?: function(self, message_id, message, sender) — function to call when the sound has finished playing or stopped manually via sound.stop.

self object The current object. message_id hash The name of the completion message, which can be either "sound_done" if the sound has finished playing, or "sound_stopped" if it was stopped manually. message table Information about the completion:

• number play_id - the sequential play identifier that was given by the sound.play function.

sender url The invoker of the callback: the sound component.

Returns

• play_id: number — The identifier for the sound voice

Stop playing all active voices or just one voice if play_id provided

// Assuming the script belongs to an instance with a sound-component with id
// "sound", this will make the component stop all playing voices:
sound.stop("#sound");
const id = sound.play("#sound");
sound.stop("#sound", { play_id: id });

Parameters

• url: string | Hash | Url — the sound component that should stop
• stop_properties?: Record<string | number, unknown> — optional table with properties: play_id number the sequential play identifier that should be stopped (was given by the sound.play() function)

Pause all active voices

// Assuming the script belongs to an instance with a sound-component with id
// "sound", this will make the component pause all playing voices:
sound.pause("#sound", true);

Parameters

• url: string | Hash | Url — the sound that should pause
• pause: boolean — true if the sound should pause

Set gain on all active playing voices of a sound.

// Assuming the script belongs to an instance with a sound-component with id
// "sound", this will set the gain to 0.9
sound.set_gain("#sound", 0.9);

Parameters

• url: string | Hash | Url — the sound to set the gain of
• gain?: number — sound gain between 0 and 1 [-60dB .. 0dB]. The final gain of the sound will be a combination of this gain, the group gain and the master gain.

Set panning on all active playing voices of a sound. The valid range is from -1.0 to 1.0, representing -45 degrees left, to +45 degrees right.

// Assuming the script belongs to an instance with a sound-component with id
// "sound", this will set the gain to 0.5
sound.set_pan("#sound", 0.5); // pan to the right

Parameters

• url: string | Hash | Url — the sound to set the panning value to
• pan?: number — sound panning between -1.0 and 1.0

The gain on the sound-component. Note that gain is in linear scale, between 0 and 1.

The pan on the sound-component. The valid range is from -1.0 to 1.0, representing -45 degrees left, to +45 degrees right.

The speed on the sound-component where 1.0 is normal speed, 0.5 is half speed and 2.0 is double speed. Valid range is 0.0 to 50.0.

The sound data used when playing the sound. The type of the property is hash.