Minor cleanup and var names, see #191

js/common/model/IntensitySample.js

@@ -37,7 +37,6 @@ define( require => {
       this.clear();
     }
 
-
     /**
      * Gets the intensity values of the rightmost column in the visible wave area.
      * @returns {number[]}
@@ -48,19 +47,21 @@ define( require => {
       for ( let i = 0; i < this.history[ 0 ].length; i++ ) {
         let sum = 0;
         for ( let k = 0; k < this.history.length; k++ ) {
-          sum = sum + this.history[ k ][ i ] * this.history[ k ][ i ]; // squared for intensity, see https://physics.info/intensity/
+
+          // squared for intensity, see https://physics.info/intensity/
+          sum = sum + this.history[ k ][ i ] * this.history[ k ][ i ];
         }
         intensities.push( sum / this.history.length );
       }
 
-      const result = [];
-      result.length = intensities.length;
-      result[ 0 ] = intensities[ 0 ];
-      result[ result.length - 1 ] = intensities[ result.length - 1 ];
+      const averagedIntensities = [];
+      averagedIntensities.length = intensities.length;
+      averagedIntensities[ 0 ] = intensities[ 0 ];
+      averagedIntensities[ averagedIntensities.length - 1 ] = intensities[ averagedIntensities.length - 1 ];
       for ( let i = 1; i < intensities.length - 1; i++ ) {
-        result[ i ] = ( intensities[ i - 1 ] + intensities[ i ] + intensities[ i + 1 ] ) / 3;
+        averagedIntensities[ i ] = ( intensities[ i - 1 ] + intensities[ i ] + intensities[ i + 1 ] ) / 3;
       }
-      return result;
+      return averagedIntensities;
     }
 
     /**

js/common/model/Lattice.js

@@ -31,7 +31,9 @@ define( require => {
   const LIGHT_VISIT_THRESHOLD = 0.06;
 
   // Damp more aggressively further from the edge of the visible lattice
-  window.damps = [ 0.999, 0.99, 0.98, 0.97, 0.95, 0.925, 0.9, 0.85, 0.8, 0.73, 0.66, 0.6, 0.55, 0.5, 0.45, 0.42, 0.4, 0.38, 0.36 ];
+  const DAMPING_PROFILE = [
+    0.999, 0.99, 0.98, 0.97, 0.95, 0.925, 0.9, 0.85, 0.8, 0.73, 0.66, 0.6, 0.55, 0.5, 0.45, 0.42, 0.4, 0.38, 0.36
+  ];
 
   class Lattice {
 
@@ -193,10 +195,9 @@ define( require => {
      * @private
      */
     decayVertical( i0, sign, width ) {
-
       for ( let j = 0; j < this.height; j++ ) {
         for ( let step = 0; step < width; step++ ) {
-          const damp = window.damps[ step ] || window.damps[ window.damps.length - 1 ];
+          const damp = DAMPING_PROFILE[ step ] || DAMPING_PROFILE[ DAMPING_PROFILE.length - 1 ];
           const i = i0 + sign * step;
           this.setCurrentValue( i, j, this.getCurrentValue( i, j ) * damp );
           this.setLastValue( i, j, this.getLastValue( i, j ) * damp );
@@ -212,10 +213,9 @@ define( require => {
      * @private
      */
     decayHorizontal( j0, sign, height ) {
-
       for ( let i = 0; i < this.width; i++ ) {
         for ( let step = 0; step < height; step++ ) {
-          const damp = window.damps[ step ] || window.damps[ window.damps.length - 1 ];
+          const damp = DAMPING_PROFILE[ step ] || DAMPING_PROFILE[ DAMPING_PROFILE.length - 1 ];
           const j = j0 + sign * step;
           this.setCurrentValue( i, j, this.getCurrentValue( i, j ) * damp );
           this.setLastValue( i, j, this.getLastValue( i, j ) * damp );

js/common/model/Scene.js

@@ -162,7 +162,6 @@ define( require => {
         validValues: WaveTemporalType.VALUES
       } );
 
-
       // The first button can trigger a pulse, or continuous wave, depending on the waveTemporalTypeProperty
       this.button1PressedProperty.lazyLink( isPressed => {
         if ( config.sceneType !== SceneType.WATER ) {
@@ -219,9 +218,6 @@ define( require => {
       // @public {BooleanProperty} - true when the second source is continuously oscillating
       this.continuousWave2OscillatingProperty = new BooleanProperty( false );
 
-      this.timeProperty.reset();
-      this.phase = 0;
-
       // When frequency changes, choose a new phase such that the new sine curve has the same value and direction
       // for continuity
       const phaseUpdate = ( newFrequency, oldFrequency ) => {
@@ -273,7 +269,7 @@ define( require => {
             // See setSourceValues
             const frequency = this.frequencyProperty.get();
             const wavelength = this.wavelength;
-            const k = Math.PI * 2 / wavelength;
+            const k = Math.PI * 2 / wavelength; // k is the wave number in sin(k*x-wt)
             const angularFrequency = frequency * Math.PI * 2;
             const x = this.modelToLatticeTransform.viewToModelX( this.lattice.dampX );
 
@@ -340,22 +336,22 @@ define( require => {
 
           // Point source
           if ( this.continuousWave1OscillatingProperty.get() || this.pulseFiringProperty.get() ) {
-            const j1 = latticeCenterJ + distanceAboveAxis;
-            lattice.setCurrentValue( WaveInterferenceConstants.POINT_SOURCE_HORIZONTAL_COORDINATE, j1, waveValue );
+            const j = latticeCenterJ + distanceAboveAxis;
+            lattice.setCurrentValue( WaveInterferenceConstants.POINT_SOURCE_HORIZONTAL_COORDINATE, j, waveValue );
             this.oscillator1Property.value = waveValue;
           }
 
           // Secondary source (note if there is only one source, this sets the same value as above)
           if ( this.continuousWave2OscillatingProperty.get() ) {
-            const j2 = latticeCenterJ - distanceAboveAxis;
-            lattice.setCurrentValue( WaveInterferenceConstants.POINT_SOURCE_HORIZONTAL_COORDINATE, j2, waveValue );
+            const j = latticeCenterJ - distanceAboveAxis;
+            lattice.setCurrentValue( WaveInterferenceConstants.POINT_SOURCE_HORIZONTAL_COORDINATE, j, waveValue );
             this.oscillator2Property.value = waveValue;
           }
         }
       }
       else {
-        // plane waves
 
+        // plane waves
         const lattice = this.lattice;
 
         // Round this to make sure it appears at an integer cell column
@@ -374,6 +370,7 @@ define( require => {
         const frequency = this.frequencyProperty.get();
         const wavelength = this.wavelength;
 
+        // Solve for the wave number
         // lambda * k = 2 * pi
         // k = 2pi/lambda
         const k = Math.PI * 2 / wavelength;

js/common/model/SoundParticle.js

@@ -17,11 +17,17 @@ define( require => {
 
     /**
      * @param {number} i - horizontal lattice coordinate of the particle
-     * @param {number} k - vertical lattice coordinate of the particle
+     * @param {number} j - vertical lattice coordinate of the particle
      * @param {number} x - initial x coordinate of the particle, in model coordinates
      * @param {number} y - initial y coordinate of the particle, in model coordinates
      */
-    constructor( i, k, x, y ) {
+    constructor( i, j, x, y ) {
+
+      // @public {number} - horizontal lattice coordinate of the particle
+      this.i = i;
+
+      // @public {number} - vertical lattice coordinate of the particle
+      this.j = j;
 
       // @public - x coordinate
       this.x = x;
@@ -34,17 +40,11 @@ define( require => {
       this.initialY = y;
       this.vx = 0;
       this.vy = 0;
-
-      // @public {number} - horizontal lattice coordinate of the particle
-      this.i = i;
-
-      // @public {number} - vertical lattice coordinate of the particle
-      this.k = k;
     }
 
     /**
      * Applies a force toward the given point with the given strength;
-     * @param {number } fx - sum of applied forces in the x direction
+     * @param {number} fx - sum of applied forces in the x direction
      * @param {number} fy - sum of applied forces in the y direction
      * @param {number} dt - time to integrate
      * @param {SoundScene} soundScene - to get the frequency range and value

js/common/view/SoundParticleLayer.js

@@ -64,7 +64,7 @@ define( require => {
     paintCanvas( context ) {
       context.transform( 1 / RESOLUTION, 0, 0, 1 / RESOLUTION, 0, 0 );
       this.model.soundScene.soundParticles.forEach( soundParticle => {
-        const isRed = ( soundParticle.i % 4 === 2 && soundParticle.k % 4 === 2 );
+        const isRed = ( soundParticle.i % 4 === 2 && soundParticle.j % 4 === 2 );
         const image = isRed ? this.redSphereImage : this.whiteSphereImage;
         context.drawImage(
           image,