Merge remote-tracking branch 'origin/master'

js/gravity-force-lab/view/ForceSoundGenerator.js

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+// Copyright 2019, University of Colorado Boulder
+
+/**
+ * sound generator for changes to the force between two masses
+ *
+ * @author John Blanco (PhET Interactive Simulations)
+ */
+define( require => {
+  'use strict';
+
+  // modules
+  const gravityForceLab = require( 'GRAVITY_FORCE_LAB/gravityForceLab' );
+  const merge = require( 'PHET_CORE/merge' );
+  const SoundClip = require( 'TAMBO/sound-generators/SoundClip' );
+
+  // constants
+  const FADE_START_DELAY = 0.2; // in seconds, time to wait before starting fade
+  const FADE_TIME = 0.15; // in seconds, duration of fade out
+  const DELAY_BEFORE_STOP = 0.1; // in seconds, amount of time from full fade to stop of sound, done to avoid glitches
+  const PITCH_RANGE_IN_SEMI_TONES = 36;
+  const PITCH_CENTER_OFFSET = 2;
+
+  // sounds
+
+  // The saturated sine loop is precisely optimized for good looping, which is why it is a .wav and not a .mp3 file
+  const forceSound = require( 'sound!GRAVITY_FORCE_LAB/saturated-sine-loop-trimmed.wav' );
+
+  class ForceSoundGenerator extends SoundClip {
+
+    /**
+     * @param {GFLBModel} model
+     * @param {BooleanProperty} resetInProgressProperty
+     * @param {Object} [options]
+     * @constructor
+     */
+    constructor( model, options ) {
+
+      options = merge( {
+        initialOutputLevel: 0.7,
+        loop: true,
+        trimSilence: false
+      }, options );
+
+      // options checking
+      assert && assert( !options || !options.loop || options.loop === true, 'must be a loop to work correctly' );
+
+      super( forceSound, options );
+
+      // @private {number} - the output level before fade out starts
+      this.nonFadedOutputLevel = options.initialOutputLevel;
+
+      // @private {number} - countdown time used for fade out
+      this.fadeCountdownTime = 0;
+
+      // start with the output level at zero so that the initial sound generation has a bit of fade in
+      this.setOutputLevel( 0, 0 );
+
+      // function for starting the force sound or adjusting the volume
+      const forceListener = force => {
+
+        if ( !model.resetInProgressProperty.value ) {
+
+          // calculate the playback rate based on the amount of force, see the design document for detailed explanation
+          const normalizedForce = Math.log( force / model.getMinForce() ) / Math.log( model.getMaxForce() / model.getMinForce() );
+          const centerForce = normalizedForce - 0.5;
+          const midiNote = PITCH_RANGE_IN_SEMI_TONES / 2 * centerForce + PITCH_CENTER_OFFSET;
+          const playbackRate = Math.pow( 2, midiNote / 12 );
+
+          this.setPlaybackRate( playbackRate );
+          this.setOutputLevel( this.nonFadedOutputLevel );
+          if ( !this.playing ) {
+            this.play();
+          }
+
+          // reset the fade countdown
+          this.fadeCountdownTime = FADE_START_DELAY + FADE_TIME + DELAY_BEFORE_STOP;
+        }
+      };
+      model.forceProperty.lazyLink( forceListener );
+
+      // @private {function}
+      this.disposeForceSoundGenerator = () => { model.forceProperty.unlink( forceListener ); };
+    }
+
+    /**
+     * @public
+     */
+    dispose() {
+      this.disposeForceSoundGenerator();
+      super.dispose();
+    }
+
+    /**
+     * step this sound generator, used for fading out the sound in the absence of user interaction
+     * @param dt
+     */
+    step( dt ) {
+      if ( this.fadeCountdownTime > 0 ) {
+        this.fadeCountdownTime = Math.max( this.fadeCountdownTime - dt, 0 );
+
+        if ( this.fadeCountdownTime < FADE_TIME + DELAY_BEFORE_STOP && this.outputLevel > 0 ) {
+
+          // the sound is fading out, adjust the output level
+          const outputLevel = Math.max(
+            ( this.fadeCountdownTime - DELAY_BEFORE_STOP ) / FADE_TIME * this.nonFadedOutputLevel,
+            0
+          );
+          this.setOutputLevel( outputLevel );
+        }
+
+        // fade out complete, stop playback
+        if ( this.fadeCountdownTime === 0 && this.isPlaying ) {
+          this.stop( 0 );
+        }
+      }
+    }
+
+    /**
+     * stop any in-progress sound generation
+     * @public
+     */
+    reset() {
+      this.stop();
+      this.fadeCountdownTime = 0;
+    }
+  }
+
+  gravityForceLab.register( 'ForceSoundGenerator', ForceSoundGenerator );
+
+  return ForceSoundGenerator;
+} );

js/gravity-force-lab/view/MassSoundGenerator.js

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+// Copyright 2019, University of Colorado Boulder
+
+/**
+ * sound generator for mass changes
+ *
+ * @author John Blanco (PhET Interactive Simulations)
+ */
+define( require => {
+  'use strict';
+
+  // modules
+  const SoundClip = require( 'TAMBO/sound-generators/SoundClip' );
+  const gravityForceLab = require( 'GRAVITY_FORCE_LAB/gravityForceLab' );
+
+  // sounds
+  const massSound = require( 'sound!GRAVITY_FORCE_LAB/rubber-band-v3.mp3' );
+
+  // constants
+  const PITCH_RANGE_IN_SEMI_TONES = 30;
+
+  class MassSoundGenerator extends SoundClip {
+
+    /**
+     * @param {NumberProperty} massProperty
+     * @param {Range} massRange
+     * @param {BooleanProperty} resetInProgressProperty
+     * @param {Object} [options]
+     * @constructor
+     */
+    constructor( massProperty, massRange, resetInProgressProperty, options ) {
+
+      // Rate changes should never affect the mass sound that is already playing.
+      options.rateChangesAffectPlayingSounds = false;
+
+      super( massSound, options );
+
+      // function for playing the mass sound
+      const massListener = mass => {
+
+        // range checking
+        assert && assert( massRange.contains( mass ), 'mass value out of range' );
+
+        if ( !resetInProgressProperty.value ) {
+
+          // convert the mass to a playback rate, see the design document for an explanation
+          const normalizedMass = ( mass - massRange.min ) / ( massRange.max - massRange.min );
+          const centerAndFlippedNormMass = ( ( 1 - normalizedMass ) - 0.5 );
+          const midiNote = PITCH_RANGE_IN_SEMI_TONES / 2 * centerAndFlippedNormMass;
+          const playbackSpeed = Math.pow( 2, midiNote / 12 );
+          this.setPlaybackRate( playbackSpeed );
+          this.play();
+        }
+      };
+      massProperty.lazyLink( massListener );
+
+      // @private {function}
+      this.disposeMassSoundGenerator = () => { massProperty.unlink( massListener ); };
+    }
+
+    /**
+     * @public
+     */
+    dispose() {
+      this.disposeMassSoundGenerator();
+      super.dispose();
+    }
+  }
+
+  gravityForceLab.register( 'MassSoundGenerator', MassSoundGenerator );
+
+  return MassSoundGenerator;
+} );

sounds/license.json

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+{
+  "rubber-band-v3.mp3": {
+    "text": [
+      "Copyright 2002-2019 University of Colorado Boulder"
+    ],
+    "projectURL": "http://phet.colorado.edu",
+    "license": "contact [email protected]",
+    "notes": "created by Ashton Morris (PhET Interactive Simulations)"
+  },
+  "saturated-sine-loop-trimmed.wav": {
+    "text": [
+      "Copyright 2002-2019 University of Colorado Boulder"
+    ],
+    "projectURL": "http://phet.colorado.edu",
+    "license": "contact [email protected]",
+    "notes": "created by Ashton Morris (PhET Interactive Simulations), edited by John Blanco"
+  },
+  "scrunched-mass-collision-sonic-womp.mp3": {
+    "text": [
+      "Copyright 2002-2019 University of Colorado Boulder"
+    ],
+    "projectURL": "http://phet.colorado.edu",
+    "license": "contact [email protected]",
+    "notes": "created by Ashton Morris (PhET Interactive Simulations)"
+  }
+}