module Eagle::Audio

Overview

The mixer: global volume, named buses, and the list of playing voices.

Eagle mixes audio in Crystal and sends it to the device, SDL on desktop and WebAudio in the browser. Browsers only allow sound after the first click or key press.

Buses group voices so players can set music and effects volume separately:

Audio.bus("music").volume = 0.5
Audio.bus("sfx").muted = true
Audio.volume = 0.8 # master volume, applies to everything
Audio.stop_all

Defined in:

eagle/audio/audio.cr

Constant Summary

SAMPLE_RATE = 48000

Output sample rate requested from the device.

TARGET_LATENCY = 0.06

Seconds of audio kept queued ahead of the device. Lower means more responsive sound but a higher risk of crackles.

Class Method Summary

• .add_stream(s : AudioStream) : AudioStream

  Starts mixing a stream.

• .bus(name : String) : Bus

  The bus called name, created on first use.

• .enabled? : Bool

  True when an audio device is open.

• .init(platform : Platform::Base) : Nil

  Opens the audio device.

• .master : Bus

  The master bus.

• .max_voices=(n : Int32)

  Caps simultaneous voices (64 by default).

• .play(sound : Sound, volume : Number = 1, pitch : Number = 1, pan : Number = 0, loop : Bool = false, bus : String = "master") : Voice

  Plays a sound and returns its voice.

• .remove_stream(s : AudioStream) : Nil

  Stops mixing a stream.

• .render(frames : Int32) : Slice(Float32)

  Mixes frames stereo frames and returns them, without touching the device.

• .sample_rate : Int32

  The actual output sample rate.

• .shutdown : Nil

  Closes the audio device.

• .stop_all : Nil

  Stops every voice and stream.

• .voice_count : Int32

  Number of voices currently playing.

• .voices : Array(Voice)

  Every voice currently playing.

• .volume : Float32

  Master volume.

• .volume=(v : Number)

  Sets the master volume.

Class Method Detail