Added PathFollower Game Object

Author: photonstorm

v3/src/gameobjects/index.js

@@ -12,8 +12,9 @@ var GameObjects = {
     Image: require('./image/Image'),
     ObjectPool: require('./pool/ObjectPool.js'),
     ParticleEmitter: require('./emitter/ParticleEmitter'),
-    Sprite: require('./sprite/Sprite'),
+    PathFollower: require('./pathfollower/PathFollower'),
     Sprite3D: require('./sprite3d/Sprite3D'),
+    Sprite: require('./sprite/Sprite'),
     StaticTilemap: require('./tilemap/static/StaticTilemap'),
     Text: require('./text/static/Text'),
     Tilemap: require('./tilemap/dynamic/Tilemap'),
@@ -30,6 +31,7 @@ var GameObjects = {
         Group: require('./group/GroupFactory'),
         Image: require('./image/ImageFactory'),
         ParticleEmitter: require('./emitter/ParticleEmitterFactory'),
+        PathFollower: require('./pathfollower/PathFollowerFactory'),
         Sprite: require('./sprite/SpriteFactory'),
         Sprite3D: require('./sprite3d/Sprite3DFactory'),
         StaticBitmapText: require('./bitmaptext/static/BitmapTextFactory'),

v3/src/gameobjects/pathfollower/PathFollower.js

@@ -0,0 +1,109 @@
+var Class = require('../../utils/Class');
+var Linear = require('../../math/easing/Linear');
+var Sprite = require('../sprite/Sprite');
+var Vector2 = require('../../math/Vector2');
+// GetEaseFunction
+
+var PathFollower = new Class({
+
+    Extends: Sprite,
+
+    initialize:
+
+    function PathFollower (scene, path, x, y, texture, frame)
+    {
+        Sprite.call(this, scene, x, y, texture, frame);
+
+        this.path = path;
+
+        this.pathOffset = new Vector2(x, y);
+        this.pathVector = new Vector2();
+
+        //  Path
+        //  Direction (forwards, backwards)
+        //  Speed (or is that controlled by the path?)
+        //  Rotate to face direction
+        //  Speed function (ease, default Linear)
+        //  Start from T along the path
+        //  Start from path x/y, or current x/y
+
+        this.isFollowing = false;
+        this.pathT = 0;
+        this.timeScale = 1;
+        this.elapsed = 0;
+        this.progress = 0;
+        this.duration = 0;
+        this.ease = Linear;
+    },
+
+    start: function (duration)
+    {
+        this.duration = duration;
+        this.isFollowing = true;
+        this.pathT = 0;
+        this.timeScale = 1;
+        this.elapsed = 0;
+        this.progress = 0;
+
+        //  path.startPoint
+
+        //  The starting point of the path, relative to this follower
+
+        var start = this.path.getStartPoint();
+        var diffX = this.pathOffset.x - start.x;
+        var diffY = this.pathOffset.y - start.y;
+
+        this.pathOffset.set(diffX, diffY);
+    },
+
+    preUpdate: function (time, delta)
+    {
+        this.anims.update(time, delta);
+
+        if (!this.isFollowing)
+        {
+            return;
+        }
+
+        //  Apply ease to pathT
+        delta *= this.timeScale;
+
+        this.elapsed += delta;
+        this.progress = Math.min(this.elapsed / this.duration, 1);
+
+        if (this.elapsed > this.duration)
+        {
+            var diff = this.elapsed - this.duration;
+            this.elapsed = this.duration;
+        }
+
+        var forward = true;
+
+        this.progress = this.elapsed / this.duration;
+
+        if (forward)
+        {
+            this.pathT = this.ease(this.progress);
+        }
+        else
+        {
+            this.pathT = this.ease(1 - this.progress);
+        }
+
+        this.path.getPoint(this.pathT, this.pathVector);
+
+        this.pathVector.add(this.pathOffset);
+
+        this.setPosition(this.pathVector.x, this.pathVector.y);
+
+        // this.setDepth(this.y);
+
+        if (this.progress === 1)
+        {
+            this.isFollowing = false;
+        }
+    }
+
+});
+
+module.exports = PathFollower;

v3/src/gameobjects/pathfollower/PathFollowerFactory.js

@@ -0,0 +1,20 @@
+var PathFollower = require('./PathFollower');
+var GameObjectFactory = require('../../scene/plugins/GameObjectFactory');
+
+//  When registering a factory function 'this' refers to the GameObjectFactory context.
+//  
+//  There are several properties available to use:
+//  
+//  this.scene - a reference to the Scene that owns the GameObjectFactory
+//  this.displayList - a reference to the Display List the Scene owns
+//  this.updateList - a reference to the Update List the Scene owns
+
+GameObjectFactory.register('follower', function (path, x, y, key, frame)
+{
+    var sprite = new PathFollower(this.scene, path, x, y, key, frame);
+
+    this.displayList.add(sprite);
+    this.updateList.add(sprite);
+
+    return sprite;
+});