fix serialization of Diffusion particles, #284

js/common/view/GasPropertiesIconFactory.ts

@@ -318,14 +318,14 @@ const GasPropertiesIconFactory = {
    * Creates an icon for particle type 1 in the Diffusion screen.
    */
   createDiffusionParticle1Icon( modelViewTransform: ModelViewTransform2, options?: ParticleNodeOptions ): Node {
-    return createParticleIcon( new DiffusionParticle1(), modelViewTransform, options );
+    return createParticleIcon( DiffusionParticle1.withDefaults(), modelViewTransform, options );
   },
 
   /**
    * Creates an icon for particle type 2 in the Diffusion screen.
    */
   createDiffusionParticle2Icon( modelViewTransform: ModelViewTransform2, options?: ParticleNodeOptions ): Node {
-    return createParticleIcon( new DiffusionParticle2(), modelViewTransform, options );
+    return createParticleIcon( DiffusionParticle2.withDefaults(), modelViewTransform, options );
   },
 
   /**

js/diffusion/model/DiffusionData.ts

@@ -87,6 +87,7 @@ export default class DiffusionData {
    * Updates Properties based on the contents of the particle arrays.
    */
   public update(): void {
+    assert && this.particleSystem.verify();
 
     let numberOfParticles1 = 0;
     let numberOfParticles2 = 0;

js/diffusion/model/DiffusionParticle.ts

@@ -6,25 +6,20 @@
  * @author Chris Malley (PixelZoom, Inc.)
  */
 
-import optionize, { EmptySelfOptions } from '../../../../phet-core/js/optionize.js';
+import { EmptySelfOptions } from '../../../../phet-core/js/optionize.js';
 import Particle, { ParticleOptions } from '../../common/model/Particle.js';
-import GasPropertiesConstants from '../../common/GasPropertiesConstants.js';
 import gasProperties from '../../gasProperties.js';
-import WithOptional from '../../../../phet-core/js/types/WithOptional.js';
+import WithRequired from '../../../../phet-core/js/types/WithRequired.js';
 
 type SelfOptions = EmptySelfOptions;
 
-export type DiffusionParticleOptions = SelfOptions & WithOptional<ParticleOptions, 'mass' | 'radius'>;
+export type DiffusionParticleOptions = SelfOptions &
+  WithRequired<ParticleOptions, 'mass' | 'radius' | 'colorProperty' | 'highlightColorProperty'>;
 
 export default class DiffusionParticle extends Particle {
 
   protected constructor( providedOptions: DiffusionParticleOptions ) {
-    super( optionize<DiffusionParticleOptions, SelfOptions, ParticleOptions>()( {
-
-      // ParticleOptions
-      mass: GasPropertiesConstants.DIFFUSION_MASS_RANGE.defaultValue,
-      radius: GasPropertiesConstants.DIFFUSION_RADIUS_RANGE.defaultValue
-    }, providedOptions ) );
+    super( providedOptions );
   }
 
   /**

js/diffusion/model/DiffusionParticle1.ts

@@ -15,6 +15,7 @@ import gasProperties from '../../gasProperties.js';
 import DiffusionParticle, { DiffusionParticleOptions } from './DiffusionParticle.js';
 import { ParticleStateObject } from '../../common/model/Particle.js';
 import IOType from '../../../../tandem/js/types/IOType.js';
+import GasPropertiesConstants from '../../common/GasPropertiesConstants.js';
 
 type SelfOptions = EmptySelfOptions;
 
@@ -25,7 +26,7 @@ export type DiffusionParticle1StateObject = ParticleStateObject;
 
 export default class DiffusionParticle1 extends DiffusionParticle {
 
-  public constructor( providedOptions?: DiffusionParticle1Options ) {
+  public constructor( providedOptions: DiffusionParticle1Options ) {
     super( optionize<DiffusionParticle1Options, SelfOptions, DiffusionParticleOptions>()( {
 
       // DiffusionParticleOptions
@@ -34,6 +35,16 @@ export default class DiffusionParticle1 extends DiffusionParticle {
     }, providedOptions ) );
   }
 
+  /**
+   * Creates a DiffusionParticle1 with default configuration. This is used for creating icons.
+   */
+  public static withDefaults(): DiffusionParticle1 {
+    return new DiffusionParticle1( {
+      mass: GasPropertiesConstants.DIFFUSION_MASS_RANGE.defaultValue,
+      radius: GasPropertiesConstants.DIFFUSION_RADIUS_RANGE.defaultValue
+    } );
+  }
+
   /**
    * Deserializes an instance of DiffusionParticle1.
    */
@@ -44,7 +55,9 @@ export default class DiffusionParticle1 extends DiffusionParticle {
       previousX: stateObject._previousX,
       previousY: stateObject._previousY,
       vx: stateObject.vx,
-      vy: stateObject.vy
+      vy: stateObject.vy,
+      mass: stateObject.mass,
+      radius: stateObject.radius
     } );
   }
 

js/diffusion/model/DiffusionParticle2.ts

@@ -15,6 +15,7 @@ import gasProperties from '../../gasProperties.js';
 import DiffusionParticle, { DiffusionParticleOptions } from './DiffusionParticle.js';
 import { ParticleStateObject } from '../../common/model/Particle.js';
 import IOType from '../../../../tandem/js/types/IOType.js';
+import GasPropertiesConstants from '../../common/GasPropertiesConstants.js';
 
 type SelfOptions = EmptySelfOptions;
 
@@ -25,7 +26,7 @@ export type DiffusionParticle2StateObject = ParticleStateObject;
 
 export default class DiffusionParticle2 extends DiffusionParticle {
 
-  public constructor( providedOptions?: DiffusionParticle2Options ) {
+  public constructor( providedOptions: DiffusionParticle2Options ) {
     super( optionize<DiffusionParticle2Options, SelfOptions, DiffusionParticleOptions>()( {
 
       // ParticleOptions
@@ -34,6 +35,16 @@ export default class DiffusionParticle2 extends DiffusionParticle {
     }, providedOptions ) );
   }
 
+  /**
+   * Creates a DiffusionParticle2 with default configuration. This is used for creating icons.
+   */
+  public static withDefaults(): DiffusionParticle2 {
+    return new DiffusionParticle2( {
+      mass: GasPropertiesConstants.DIFFUSION_MASS_RANGE.defaultValue,
+      radius: GasPropertiesConstants.DIFFUSION_RADIUS_RANGE.defaultValue
+    } );
+  }
+
   /**
    * Deserializes an instance of DiffusionParticle1.
    */
@@ -44,7 +55,9 @@ export default class DiffusionParticle2 extends DiffusionParticle {
       previousX: stateObject._previousX,
       previousY: stateObject._previousY,
       vx: stateObject.vx,
-      vy: stateObject.vy
+      vy: stateObject.vy,
+      mass: stateObject.mass,
+      radius: stateObject.radius
     } );
   }
 

js/diffusion/model/DiffusionParticleSystem.ts

@@ -244,6 +244,26 @@ export default class DiffusionParticleSystem extends PhetioObject {
     this.centerOfMass2Property.value = ParticleUtils.getCenterXOfMass( this.particles2, this.container.width / 2 );
   }
 
+  /**
+   * Verifies that the particles system is in a consistent state.
+   */
+  public verify(): void {
+    this.verifyParticles( this.particles1, this.particle1Settings );
+    this.verifyParticles( this.particles2, this.particle2Settings );
+  }
+
+  /**
+   * Verifies that all particles of the same type have the same mass and radius.
+   */
+  private verifyParticles( particles: DiffusionParticle[], settings: DiffusionSettings ): void {
+    if ( particles.length > 0 ) {
+      assert && assert( _.every( particles, particle => ( particle.mass === settings.massProperty.value ) ),
+        'Particles do not have consistent mass.' );
+      assert && assert( _.every( particles, particle => ( particle.radius === settings.radiusProperty.value ) ),
+        'Particles do not have consistent radius.' );
+    }
+  }
+
   /**
    * DiffusionParticleSystemIO handles serialization of the particle arrays. It implements reference-type serialization,
    * as described in https://github.com/phetsims/phet-io/blob/main/doc/phet-io-instrumentation-technical-guide.md#serialization.

js/diffusion/view/DiffusionParticleSystemNode.ts

@@ -27,14 +27,14 @@ export default class DiffusionParticleSystemNode extends ParticlesNode {
 
     // generated canvas for DiffusionParticle1 species
     const particle1CanvasProperty = new DiffusionParticleCanvasProperty(
-      new DiffusionParticle1(),
+      DiffusionParticle1.withDefaults(),
       model.modelViewTransform,
       model.particleSystem.particle1Settings.radiusProperty
     );
 
     // generated canvas for DiffusionParticle2 species
     const particle2CanvasProperty = new DiffusionParticleCanvasProperty(
-      new DiffusionParticle2(),
+      DiffusionParticle2.withDefaults(),
       model.modelViewTransform,
       model.particleSystem.particle2Settings.radiusProperty
     );