Audio oscillator

demos/demos/audio/audioOscillator.js

@@ -0,0 +1,28 @@
+import {
+  Demo,
+  World,
+  AudioOscillator,
+  EntityCommands,
+  Cleanup
+} from 'wima'
+import { addDefaultCamera3D } from '../utils.js'
+
+export default new Demo(
+  'audio/audio oscillator',
+  [init, addDefaultCamera3D]
+)
+
+/**
+ * @param {World} world
+ */
+function init(world) {
+  const commands = world.getResource(EntityCommands)
+
+  commands
+    .spawn()
+    .insertPrefab([
+      new AudioOscillator(),
+      new Cleanup()
+    ])
+    .build()
+}

demos/demos/audio/index.js

@@ -1,2 +1,3 @@
 export { default as audioGraph } from './audioGraph.js'
-export { default as audioPlayer } from './audioPlayer.js'
+export { default as audioPlayer } from './audioPlayer.js'
+export { default as audioOscillator } from './audioOscillator.js'

demos/main.js

@@ -21,6 +21,7 @@ import {
   despawn,
   audioGraph,
   audioPlayer,
+  audioOscillator,
   keyboard,
   mouse,
   touch,
@@ -71,6 +72,7 @@ app
       touch,
       audioGraph,
       audioPlayer,
+      audioOscillator,
       lineStyle2d,
       arcs2d,
       shapes2d,

src/audio/components/audiooscillator.js

@@ -0,0 +1,89 @@
+/** @import { NodeId } from '../../datastructures/index.js' */
+/** @import { ComponentHook } from '../../ecs/index.js' */
+import { Timer } from '../../time/index.js'
+import { AudioGraph } from '../resources/index.js'
+
+export class AudioOscillator {
+
+  /**
+   * @type {NodeId | undefined}
+   */
+  sourceNode
+
+  /**
+   * @type {AudioOscillatorType}
+   */
+  type
+
+  /**
+   * @type {NodeId | undefined}
+   */
+  attach
+
+  /**
+   * @type {number}
+   */
+  detune
+
+  /**
+   * @type {number}
+   */
+  frequency
+
+  /**
+   * @type {Timer}
+   */
+  playback = new Timer({ duration:1000000 })
+
+  /**
+   * @param {AudioOscillatorOptions} [options]
+   */
+  constructor({
+    attach, 
+    type = AudioOscillatorType.Sine,
+    detune = 0,
+    frequency = 440
+  } = {}) {
+    this.attach = attach
+    this.type = type
+    this.detune = detune
+    this.frequency = frequency
+  }
+}
+
+/**
+ * @type {ComponentHook}
+ */
+export function removeOscillatorSink(entity, world) {
+  const graph = world.getResource(AudioGraph)
+  const audio = world.get(entity, AudioOscillator)
+
+  // SAFETY: The node referenced by the player is guaranteed to be a `OscillatorNode`.
+  const node = /** @type {OscillatorNode | undefined} */ (graph.graph.getNode(audio.sourceNode)?.weight)
+
+  if (node) {
+    node.stop()
+
+    // TODO: Remove the audio sink from the graph when removing nodes on a graph
+    // is available.
+  }
+}
+
+/**
+ * @readonly
+ * @enum {number}
+ */
+export const AudioOscillatorType = {
+  SawTooth: 0,
+  Sine: 1,
+  Triangle: 2,
+  Square: 3
+}
+
+/**
+ * @typedef AudioOscillatorOptions
+ * @property {NodeId} [attach]
+ * @property {AudioOscillatorType} [type]
+ * @property {number} [frequency]
+ * @property {number} [detune]
+ */

src/audio/components/index.js

@@ -1 +1,2 @@
-export * from './audioplayer.js'
+export * from './audioplayer.js'
+export * from './audiooscillator.js'

src/audio/plugin.js

@@ -3,10 +3,10 @@ import { AssetParserPlugin, AssetPlugin, Assets } from '../asset/index.js'
 import { ComponentHooks } from '../ecs/index.js'
 import { typeidGeneric } from '../reflect/index.js'
 import { Audio } from './assets/index.js'
-import { AudioPlayer, removeAudioPlayerSink } from './components/index.js'
+import { AudioPlayer, AudioOscillator, removeAudioPlayerSink, removeOscillatorSink } from './components/index.js'
 import { AudioAdded, AudioDropped, AudioModified } from './events/index.js'
 import { AudioCommands, AudioParser, AudioAssets, AudioGraph } from './resources/index.js'
-import { playAudio, updatePlayers } from './systems/index.js'
+import { playAudio, updatePlayers, playOscillators, updateOscillators } from './systems/index.js'
 
 export class AudioPlugin extends Plugin {
 
@@ -23,6 +23,11 @@ export class AudioPlugin extends Plugin {
         null,
         removeAudioPlayerSink
       ))
+      .registerType(AudioOscillator)
+      .setComponentHooks(AudioOscillator, new ComponentHooks(
+        null,
+        removeOscillatorSink
+      ))
       .setResource(new AudioGraph())
       .setResource(handler)
       .registerPlugin(new AssetPlugin({
@@ -38,7 +43,9 @@ export class AudioPlugin extends Plugin {
         parser: new AudioParser()
       }))
       .registerSystem(AppSchedule.Update, playAudio)
+      .registerSystem(AppSchedule.Update, playOscillators)
       .registerSystem(AppSchedule.Update, updatePlayers)
+      .registerSystem(AppSchedule.Update, updateOscillators)
 
     window.addEventListener('pointerdown', resumeAudio)
 

src/audio/systems/index.js

@@ -1,7 +1,7 @@
 import { Query, World } from '../../ecs/index.js'
 import { VirtualClock, TimerMode } from '../../time/index.js'
 import { AudioAssets, AudioGraph } from '../resources/index.js'
-import { AudioPlayer } from '../components/index.js'
+import { AudioPlayer, AudioOscillator, AudioOscillatorType } from '../components/index.js'
 
 
 /**
@@ -48,6 +48,42 @@ export function playAudio(world) {
   })
 }
 
+/**
+ * @param {World} world
+ */
+export function playOscillators(world) {
+  const graph = world.getResource(AudioGraph)
+  const oscillators = new Query(world, [AudioOscillator])
+  const ctx = graph.getContext()
+  const root = graph.getRoot()
+
+
+  oscillators.each(([oscillator]) => {
+    const { type, frequency, sourceNode, detune, playback, attach } = oscillator
+
+    if (sourceNode) {
+
+      // update node if a playback is requested
+    } else {
+      const node = new OscillatorNode(ctx, {
+        detune,
+        frequency,
+        type: mapType(type)
+      })
+      const id = graph.add(node)
+
+      if (attach) {
+        graph.connect(id, attach)
+      } else {
+        graph.connect(id, root)
+      }
+
+      node.start(playback.elapsed())
+      oscillator.sourceNode = id
+    }
+  })
+}
+
 /**
  * @param {World} world
  */
@@ -61,6 +97,19 @@ export function updatePlayers(world) {
   })
 }
 
+/**
+ * @param {World} world
+ */
+export function updateOscillators(world) {
+  const oscillators = new Query(world, [AudioOscillator])
+  const clock = world.getResource(VirtualClock)
+  const delta = clock.getDelta()
+
+  oscillators.each(([oscillator]) => {
+    oscillator.playback.update(delta)
+  })
+}
+
 /**
  * @param {TimerMode} playbackMode
  */
@@ -75,4 +124,28 @@ function looped(playbackMode) {
     default:
       return false
   }
+}
+
+/**
+ * @param {AudioOscillatorType} type
+ * @throws {string}
+ * @returns {OscillatorType}
+ */
+function mapType(type) {
+  switch (type) {
+    case AudioOscillatorType.SawTooth:
+      return 'sawtooth'
+
+    case AudioOscillatorType.Sine:
+      return 'sine'
+
+    case AudioOscillatorType.Square:
+      return 'square'
+
+    case AudioOscillatorType.Triangle:
+      return 'triangle'
+
+    default:
+      throw 'No such `AudioOscillatorType` exists.'
+  }
 }