From 98a6ee5f78fbdb732f1aae5c7d5f6827b67b3977 Mon Sep 17 00:00:00 2001
From: jbphet <john.blanco@colorado.edu>
Date: Tue, 5 Nov 2019 11:37:37 -0700
Subject: [PATCH] consolidated boundary sound generation, consolidated into a
 sound generator, see https://github.com/phetsims/gravity-force-lab/issues/181

---
 .../view/BoundarySoundGenerator.js            | 64 +++++++++++++++++++
 .../view/GravityForceLabScreenView.js         | 10 +++
 2 files changed, 74 insertions(+)
 create mode 100644 js/gravity-force-lab/view/BoundarySoundGenerator.js

diff --git a/js/gravity-force-lab/view/BoundarySoundGenerator.js b/js/gravity-force-lab/view/BoundarySoundGenerator.js
new file mode 100644
index 00000000..7f4063b9
--- /dev/null
+++ b/js/gravity-force-lab/view/BoundarySoundGenerator.js
@@ -0,0 +1,64 @@
+// Copyright 2019, University of Colorado Boulder
+
+/**
+ * BoundarySoundGenerator generates the sounds that indicate when the masses have reached their inner and outer motion
+ * limits.
+ *
+ * @author John Blanco (PhET Interactive Simulations)
+ */
+define( require => {
+  'use strict';
+
+  // modules
+  const gravityForceLab = require( 'GRAVITY_FORCE_LAB/gravityForceLab' );
+  const SoundClip = require( 'TAMBO/sound-generators/SoundClip' );
+  const SoundGenerator = require( 'TAMBO/sound-generators/SoundGenerator' );
+
+  // sounds
+  const innerBoundarySoundInfo = require( 'sound!GRAVITY_FORCE_LAB/scrunched-mass-collision-sonic-womp.mp3' );
+  const outerBoundarySoundInfo = require( 'sound!TAMBO/boundary-reached.mp3' );
+
+  class BoundarySoundGenerator extends SoundGenerator {
+
+    /**
+     * @param {ISLCObject} movableObject
+     * @param {ISLCModel} model
+     * @param {Object} [options]
+     */
+    constructor( movableObject, model, options ) {
+
+      super( options );
+
+      const innerBoundarySoundClip = new SoundClip( innerBoundarySoundInfo );
+      innerBoundarySoundClip.connect( this.masterGainNode );
+      const outerBoundarySoundClip = new SoundClip( outerBoundarySoundInfo );
+      outerBoundarySoundClip.connect( this.masterGainNode );
+
+      // function for starting the force sound or adjusting the volume
+      const positionListener = position => {
+        if ( position === model.getObjectMinPosition( movableObject ) ) {
+          innerBoundarySoundClip.play();
+        }
+        else if ( position === model.getObjectMaxPosition( movableObject ) ) {
+          outerBoundarySoundClip.play();
+        }
+      };
+      movableObject.positionProperty.link( positionListener );
+
+      // @private {function}
+      this.disposeBoundarySoundGenerator = () => { movableObject.positionProperty.unlink( positionListener ); };
+    }
+
+    /**
+     * @public
+     */
+    dispose() {
+      this.disposeBoundarySoundGenerator();
+      super.dispose();
+    }
+  }
+
+  gravityForceLab.register( 'BoundarySoundGenerator', BoundarySoundGenerator );
+
+  return BoundarySoundGenerator;
+} );
\ No newline at end of file
diff --git a/js/gravity-force-lab/view/GravityForceLabScreenView.js b/js/gravity-force-lab/view/GravityForceLabScreenView.js
index b6f7c2b8..ad9fa320 100644
--- a/js/gravity-force-lab/view/GravityForceLabScreenView.js
+++ b/js/gravity-force-lab/view/GravityForceLabScreenView.js
@@ -12,6 +12,7 @@ define( require => {
 
   // modules
   const AccessiblePeer = require( 'SCENERY/accessibility/AccessiblePeer' );
+  const BoundarySoundGenerator = require( 'GRAVITY_FORCE_LAB/gravity-force-lab/view/BoundarySoundGenerator' );
   const Bounds2 = require( 'DOT/Bounds2' );
   const DefaultDirection = require( 'INVERSE_SQUARE_LAW_COMMON/view/DefaultDirection' );
   const ForceSoundGenerator = require( 'GRAVITY_FORCE_LAB/gravity-force-lab/view/ForceSoundGenerator' );
@@ -68,6 +69,7 @@ define( require => {
   const OBJECT_ONE = ISLCObjectEnum.OBJECT_ONE;
   const OBJECT_TWO = ISLCObjectEnum.OBJECT_TWO;
   const CHECKBOX_TEXT_SIZE = 15;
+  const BOUNDARY_SOUNDS_LEVEL = 1;
 
   function GravityForceLabScreenView( model, tandem ) {
 
@@ -348,6 +350,14 @@ define( require => {
       resetAllButton.buttonModel.isFiringProperty,
       { initialOutputLevel: 0.7, lockoutTime: 0.2 }
     ) );
+
+    // sound generation for masses reaching the inner or outer motion boundaries
+    soundManager.addSoundGenerator( new BoundarySoundGenerator( model.object1, model, {
+      initialOutputLevel: BOUNDARY_SOUNDS_LEVEL
+    } ) );
+    soundManager.addSoundGenerator( new BoundarySoundGenerator( model.object2, model, {
+      initialOutputLevel: BOUNDARY_SOUNDS_LEVEL
+    } ) );
   }
 
   gravityForceLab.register( 'GravityForceLabScreenView', GravityForceLabScreenView );