github.com/atsaki/terraform@v0.4.3-0.20150919165407-25bba5967654/website/source/assets/javascripts/app/Engine.Point.Puller.js (about)

     1  (function(
     2  	Engine,
     3  	Vector
     4  ){
     5  
     6  Engine.Point.Puller = function(id, x, y, shapeSize){
     7  	this.id = id;
     8  
     9  	this.shapeSize = shapeSize;
    10  	this.ref = new Vector(x, y);
    11  
    12  	this.pos = new Vector(
    13  		x * shapeSize.x,
    14  		y * shapeSize.y
    15  	);
    16  
    17  	this.home  = this.pos.clone();
    18  	this.accel = Vector.coerce(this.accel);
    19  	this.vel   = Vector.coerce(this.vel);
    20  };
    21  
    22  Engine.Point.Puller.prototype = {
    23  
    24  	fillStyle: null,
    25  	defaultFillstyle: '#b976ff',
    26  	chasingFillstyle: '#ff6b6b',
    27  
    28  	radius: 1,
    29  
    30  	maxSpeed: 160,
    31  	maxForce: 50,
    32  
    33  	pos: {
    34  		x: 0,
    35  		y: 0
    36  	},
    37  
    38  	accel: {
    39  		x: 0,
    40  		y: 0
    41  	},
    42  
    43  	vel: {
    44  		x: 0,
    45  		y: 0
    46  	},
    47  
    48  	aRad: 200,
    49  
    50  	safety: 0.25,
    51  
    52  	resize: function(){
    53  		this.home.x = this.pos.x = this.ref.x * this.shapeSize.x;
    54  		this.home.y = this.pos.y = this.ref.y * this.shapeSize.y;
    55  
    56  		return this;
    57  	},
    58  
    59  	update: function(engine){
    60  		var target = Vector.coerce(engine.mouse),
    61  			distanceToMouse, toHome, mag, safety;
    62  
    63  		target.x += (this.shapeSize.x - engine.width)  / 2;
    64  		target.y += (this.shapeSize.y - engine.height) / 2;
    65  
    66  		distanceToMouse = this.distanceTo(target);
    67  
    68  		this.accel.mult(0);
    69  
    70  		if (distanceToMouse < this.aRad) {
    71  			this._chasing = true;
    72  			this.toChase(target);
    73  			this.fillStyle = this.chasingFillstyle;
    74  		} else {
    75  			this._chasing = false;
    76  			this.fillStyle = this.defaultFillstyle;
    77  		}
    78  
    79  		this.toChase(this.home, this.maxForce / 2);
    80  
    81  		this.vel.add(this.accel);
    82  		this.pos.add(
    83  			Vector.mult(this.vel, engine.tick)
    84  		);
    85  
    86  		toHome = Vector.sub(this.home, this.pos);
    87  		mag = toHome.mag();
    88  		safety = this.aRad * (this.safety * 3);
    89  		if (mag > this.aRad - safety) {
    90  			toHome.normalize();
    91  			toHome.mult(this.aRad - safety);
    92  			this.pos = Vector.sub(this.home, toHome);
    93  		}
    94  
    95  		target = null;
    96  		toHome = null;
    97  		return this;
    98  	},
    99  
   100  	toChase: function(target, maxForce){
   101  		var desired, steer, distance, mult, safety;
   102  
   103  		maxForce = maxForce || this.maxForce;
   104  
   105  		target = Vector.coerce(target);
   106  		desired = Vector.sub(target, this.pos);
   107  		distance = desired.mag();
   108  		desired.normalize();
   109  
   110  		safety = this.aRad * this.safety;
   111  
   112  		if (distance < safety) {
   113  			mult = Engine.map(distance, 0, safety, 0, this.maxSpeed);
   114  		} else if (distance > this.aRad - safety){
   115  			mult = Engine.map(this.aRad - distance, 0, safety, 0, this.maxSpeed);
   116  		} else {
   117  			mult = this.maxSpeed;
   118  		}
   119  
   120  		desired.mult(mult);
   121  
   122  		steer = Vector.sub(desired, this.vel);
   123  		steer.limit(maxForce);
   124  		this.accel.add(steer);
   125  
   126  		target = null;
   127  		desired = null;
   128  		steer = null;
   129  	},
   130  
   131  	draw: function(ctx, scale){
   132  		ctx.fillStyle = this.fillStyle;
   133  		ctx.fillRect(
   134  			(this.pos.x - this.radius / 2) * scale >> 0,
   135  			(this.pos.y - this.radius / 2) * scale >> 0,
   136  			this.radius * scale,
   137  			this.radius * scale
   138  		);
   139  
   140  		return this;
   141  	},
   142  
   143  	distanceTo: function(target) {
   144  		var xd = this.home.x - target.x;
   145  		var yd = this.home.y - target.y;
   146  		return Math.sqrt(xd * xd + yd * yd );
   147  	}
   148  };
   149  
   150  })(
   151  	window.Engine,
   152  	window.Vector
   153  );