feat(gameObject): add angular velocity and acceleration

docs/pages/reducing-file-size.js

@@ -83,14 +83,14 @@ __Note:__ Some of the more advance classes – such as Button or Grid – requir
 
 | Name            | Functionality Enabled |
 | --------------- | ------------- |
-| `acceleration`  | `acceleration`, `ddx`, `ddy` |
+| `acceleration`  | `acceleration`, `ddx`, `ddy`, 'ddrotation' |
 | `anchor`        | `anchor` |
 | `group`         | `children`, `parent`, `addChild`, `removeChild` |
 | `opacity`       | `opacity` |
 | `rotation`      | `rotation` |
 | `scale`         | `scaleX`, `scaleY`, `setScale()` |
 | `ttl`           | `ttl`, `isAlive` |
-| `velocity`      | `velocity`, `dx`, `dy` |
+| `velocity`      | `velocity`, `dx`, `dy`, 'drotation' |
 
 #### `sprite` Options:
 

src/gameObject.js

@@ -28,6 +28,8 @@ import { noop, removeFromArray } from './utils.js';
  * @param {GameObject[]} [properties.children] - Children to add to the game object.
  * @param {Number} [properties.opacity=1] - The opacity of the game object.
  * @param {Number} [properties.rotation=0] - The rotation around the anchor in radians.
+ * @param {Number} [properties.drotation=0] - The angular velocity of the rotation in radians.
+ * @param {Number} [properties.ddrotation=0] - The angular acceleration of the rotation in radians.
  * @param {Number} [properties.scaleX=1] - The x scale of the game object.
  * @param {Number} [properties.scaleY=1] - The y scale of the game object.
  *
@@ -164,6 +166,24 @@ class GameObject extends Updatable {
      * @property {Number} rotation
      */
     rotation = 0,
+
+    // @ifdef GAMEOBJECT_VELOCITY
+    /**
+     * Angular velocity of the rotation in radians.
+     * @memberof GameObject
+     * @property {Number} drotation
+     */
+    drotation = 0,
+    // @endif
+
+    // @ifdef GAMEOBJECT_ACCELERATION
+    /**
+     * Angular acceleration of the rotation in radians.
+     * @memberof GameObject
+     * @property {Number} ddrotation
+     */
+    ddrotation = 0,
+    // @endif
     // @endif
 
     // @ifdef GAMEOBJECT_SCALE
@@ -208,6 +228,14 @@ class GameObject extends Updatable {
 
       // @ifdef GAMEOBJECT_ROTATION
       rotation,
+
+      // @ifdef GAMEOBJECT_VELOCITY
+      drotation,
+      // @endif
+
+      // @ifdef GAMEOBJECT_ACCELERATION
+      ddrotation,
+      // @endif
       // @endif
 
       // @ifdef GAMEOBJECT_SCALE
@@ -626,6 +654,21 @@ class GameObject extends Updatable {
     this._rot = value;
     this._pc();
   }
+
+  // @ifdef GAMEOBJECT_VELOCITY||GAMEOBJECT_ACCELERATION
+  advance(dt) {
+    super.advance(dt);
+
+    // @ifdef GAMEOBJECT_VELOCITY
+    // @ifdef GAMEOBJECT_ACCELERATION
+    this.drotation += this.ddrotation;
+    // @endif
+
+    this.rotation += this.drotation;
+    // @endif
+  }
+  // @endif
+
   // @endif
 
   // --------------------------------------------------

test/typings/gameObject.ts

@@ -10,6 +10,8 @@ let height: number = gameObject.height;
 let context: CanvasRenderingContext2D = gameObject.context;
 let children: kontra.GameObject[] = gameObject.children;
 let rotation: number = gameObject.rotation;
+let drotation: number = gameObject.drotation;
+let ddrotation: number = gameObject.ddrotation;
 let ttl: number = gameObject.ttl;
 let anchor: {x: number, y: number} = gameObject.anchor;
 let sx: number = gameObject.sx;
@@ -62,6 +64,8 @@ kontra.GameObject({
   ddy: 2,
   ttl: 10,
   rotation: 10,
+  drotation: 10,
+  ddrotation: 12,
   anchor: {x: 2, y: 2},
   scaleX: 2,
   scaleY: 2,

test/unit/gameObject.spec.js

@@ -2,14 +2,17 @@ import GameObject, { GameObjectClass } from '../../src/gameObject.js';
 import { _reset, init, getContext } from '../../src/core.js';
 import { noop } from '../../src/utils.js';
 import { degToRad } from '../../src/helpers.js';
+import Vector from '../../src/vector.js';
 
 // test-context:start
 let testContext = {
   GAMEOBJECT_ANCHOR: true,
   GAMEOBJECT_GROUP: true,
   GAMEOBJECT_OPACITY: true,
   GAMEOBJECT_ROTATION: true,
-  GAMEOBJECT_SCALE: true
+  GAMEOBJECT_SCALE: true,
+  GAMEOBJECT_VELOCITY: true,
+  GAMEOBJECT_ACCELERATION: true
 };
 // test-context:end
 
@@ -177,7 +180,7 @@ describe(
       }
 
       if (testContext.GAMEOBJECT_ROTATION) {
-        it('should set default camera', () => {
+        it('should set default rotation', () => {
           expect(gameObject.rotation).to.equal(0);
         });
 
@@ -187,13 +190,51 @@ describe(
           expect(gameObject.rotation).to.equal(0.5);
         });
       } else {
-        it('should not default camera', () => {
+        it('should not default rotation', () => {
           expect(gameObject.rotation).to.not.exist;
         });
       }
 
+      if (
+        testContext.GAMEOBJECT_ROTATION &&
+        testContext.GAMEOBJECT_VELOCITY
+      ) {
+        it('should set default drotation', () => {
+          expect(gameObject.drotation).to.equal(0);
+        });
+
+        it('should set drotation property', () => {
+          gameObject = GameObject({ drotation: 0.5 });
+
+          expect(gameObject.drotation).to.equal(0.5);
+        });
+      } else {
+        it('should not default drotation', () => {
+          expect(gameObject.drotation).to.not.exist;
+        });
+      }
+
+      if (
+        testContext.GAMEOBJECT_ROTATION &&
+        testContext.GAMEOBJECT_ACCELERATION
+      ) {
+        it('should set default ddrotation', () => {
+          expect(gameObject.ddrotation).to.equal(0);
+        });
+
+        it('should set ddrotation property', () => {
+          gameObject = GameObject({ ddrotation: 0.5 });
+
+          expect(gameObject.ddrotation).to.equal(0.5);
+        });
+      } else {
+        it('should not default ddrotation', () => {
+          expect(gameObject.ddrotation).to.not.exist;
+        });
+      }
+
       if (testContext.GAMEOBJECT_SCALE) {
-        it('should set default camera', () => {
+        it('should set default scale', () => {
           expect(gameObject.scaleX).to.equal(1);
           expect(gameObject.scaleY).to.equal(1);
         });
@@ -205,7 +246,7 @@ describe(
           expect(gameObject.scaleY).to.equal(20);
         });
       } else {
-        it('should not default camera', () => {
+        it('should not default scale', () => {
           expect(gameObject.scaleY).to.not.exist;
           expect(gameObject.scaleY).to.not.exist;
         });
@@ -692,6 +733,66 @@ describe(
       }
     });
 
+    // --------------------------------------------------
+    // advance
+    // --------------------------------------------------
+    describe('advance', () => {
+      if (
+        (testContext.GAMEOBJECT_ROTATION &&
+          testContext.GAMEOBJECT_VELOCITY) ||
+        testContext.GAMEOBJECT_ACCELERATION
+      ) {
+        it('should call parent advance', () => {
+          gameObject.position = Vector(5, 10);
+          gameObject.velocity = Vector(15, 20);
+
+          gameObject.advance();
+
+          expect(gameObject.position.x).to.equal(20);
+          expect(gameObject.position.y).to.equal(30);
+        });
+      }
+
+      if (
+        testContext.GAMEOBJECT_ROTATION &&
+        testContext.GAMEOBJECT_VELOCITY &&
+        testContext.GAMEOBJECT_ACCELERATION
+      ) {
+        it('should add the angular acceleration to the angular velocity', () => {
+          gameObject.drotation = 0.5;
+          gameObject.ddrotation = 0.5;
+
+          gameObject.advance();
+
+          expect(gameObject.drotation).to.equal(1);
+        });
+      }
+
+      if (
+        testContext.GAMEOBJECT_ROTATION &&
+        testContext.GAMEOBJECT_VELOCITY
+      ) {
+        it('should add the angular velocity to the rotation', () => {
+          gameObject.rotation = 0.5;
+          gameObject.drotation = 0.5;
+
+          gameObject.advance();
+
+          expect(gameObject.rotation).to.equal(1);
+        });
+      } else {
+        it('should not modify the rotation', () => {
+          gameObject.rotation = 0;
+          gameObject.drotation = 0.5;
+          gameObject.ddrotation = 0.5;
+
+          gameObject.advance();
+
+          expect(gameObject.rotation).to.equal(0);
+        });
+      }
+    });
+
     // --------------------------------------------------
     // group
     // --------------------------------------------------