var Easing = {
	// t: current time, b: begInnIng value, c: change In value, d: duration
	swing: function (x, t, b, c, d) {
		if (arguments.length === 1) {
			t = arguments[0]; x = 0; b = 0; c = 1; d = 1;
		}
		return Easing.easeOutQuad(x, t, b, c, d);
	},
	easeInQuad: function (x, t, b, c, d) {
		if (arguments.length === 1) {
			t = arguments[0]; x = 0; b = 0; c = 1; d = 1;
		}
		return c*(t/=d)*t + b;
	},
	easeOutQuad: function (x, t, b, c, d) {
		if (arguments.length === 1) {
			t = arguments[0]; x = 0; b = 0; c = 1; d = 1;
		}
		return -c *(t/=d)*(t-2) + b;
	},
	easeInOutQuad: function (x, t, b, c, d) {
		if (arguments.length === 1) {
			t = arguments[0]; x = 0; b = 0; c = 1; d = 1;
		}
		if ((t/=d/2) < 1) return c/2*t*t + b;
		return -c/2 * ((--t)*(t-2) - 1) + b;
	},
	easeInCubic: function (x, t, b, c, d) {
		if (arguments.length === 1) {
			t = arguments[0]; x = 0; b = 0; c = 1; d = 1;
		}
		return c*(t/=d)*t*t + b;
	},
	easeOutCubic: function (x, t, b, c, d) {
		if (arguments.length === 1) {
			t = arguments[0]; x = 0; b = 0; c = 1; d = 1;
		}
		return c*((t=t/d-1)*t*t + 1) + b;
	},
	easeInOutCubic: function (x, t, b, c, d) {
		if (arguments.length === 1) {
			t = arguments[0]; x = 0; b = 0; c = 1; d = 1;
		}
		if ((t/=d/2) < 1) return c/2*t*t*t + b;
		return c/2*((t-=2)*t*t + 2) + b;
	},
	easeInQuart: function (x, t, b, c, d) {
		if (arguments.length === 1) {
			t = arguments[0]; x = 0; b = 0; c = 1; d = 1;
		}
		return c*(t/=d)*t*t*t + b;
	},
	easeOutQuart: function (x, t, b, c, d) {
		if (arguments.length === 1) {
			t = arguments[0]; x = 0; b = 0; c = 1; d = 1;
		}
		return -c * ((t=t/d-1)*t*t*t - 1) + b;
	},
	easeInOutQuart: function (x, t, b, c, d) {
		if (arguments.length === 1) {
			t = arguments[0]; x = 0; b = 0; c = 1; d = 1;
		}
		if ((t/=d/2) < 1) return c/2*t*t*t*t + b;
		return -c/2 * ((t-=2)*t*t*t - 2) + b;
	},
	easeInQuint: function (x, t, b, c, d) {
		if (arguments.length === 1) {
			t = arguments[0]; x = 0; b = 0; c = 1; d = 1;
		}
		return c*(t/=d)*t*t*t*t + b;
	},
	easeOutQuint: function (x, t, b, c, d) {
		if (arguments.length === 1) {
			t = arguments[0]; x = 0; b = 0; c = 1; d = 1;
		}
		return c*((t=t/d-1)*t*t*t*t + 1) + b;
	},
	easeInOutQuint: function (x, t, b, c, d) {
		if (arguments.length === 1) {
			t = arguments[0]; x = 0; b = 0; c = 1; d = 1;
		}
		if ((t/=d/2) < 1) return c/2*t*t*t*t*t + b;
		return c/2*((t-=2)*t*t*t*t + 2) + b;
	},
	easeInSine: function (x, t, b, c, d) {
		if (arguments.length === 1) {
			t = arguments[0]; x = 0; b = 0; c = 1; d = 1;
		}
		return -c * Math.cos(t/d * (Math.PI/2)) + c + b;
	},
	easeOutSine: function (x, t, b, c, d) {
		if (arguments.length === 1) {
			t = arguments[0]; x = 0; b = 0; c = 1; d = 1;
		}
		return c * Math.sin(t/d * (Math.PI/2)) + b;
	},
	easeInOutSine: function (x, t, b, c, d) {
		if (arguments.length === 1) {
			t = arguments[0]; x = 0; b = 0; c = 1; d = 1;
		}
		return -c/2 * (Math.cos(Math.PI*t/d) - 1) + b;
	},
	easeInExpo: function (x, t, b, c, d) {
		if (arguments.length === 1) {
			t = arguments[0]; x = 0; b = 0; c = 1; d = 1;
		}
		return (t==0) ? b : c * Math.pow(2, 10 * (t/d - 1)) + b;
	},
	easeOutExpo: function (x, t, b, c, d) {
		if (arguments.length === 1) {
			t = arguments[0]; x = 0; b = 0; c = 1; d = 1;
		}
		return (t==d) ? b+c : c * (-Math.pow(2, -10 * t/d) + 1) + b;
	},
	easeInOutExpo: function (x, t, b, c, d) {
		if (arguments.length === 1) {
			t = arguments[0]; x = 0; b = 0; c = 1; d = 1;
		}
		if (t==0) return b;
		if (t==d) return b+c;
		if ((t/=d/2) < 1) return c/2 * Math.pow(2, 10 * (t - 1)) + b;
		return c/2 * (-Math.pow(2, -10 * --t) + 2) + b;
	},
	easeInCirc: function (x, t, b, c, d) {
		if (arguments.length === 1) {
			t = arguments[0]; x = 0; b = 0; c = 1; d = 1;
		}
		return -c * (Math.sqrt(1 - (t/=d)*t) - 1) + b;
	},
	easeOutCirc: function (x, t, b, c, d) {
		if (arguments.length === 1) {
			t = arguments[0]; x = 0; b = 0; c = 1; d = 1;
		}
		return c * Math.sqrt(1 - (t=t/d-1)*t) + b;
	},
	easeInOutCirc: function (x, t, b, c, d) {
		if (arguments.length === 1) {
			t = arguments[0]; x = 0; b = 0; c = 1; d = 1;
		}
		if ((t/=d/2) < 1) return -c/2 * (Math.sqrt(1 - t*t) - 1) + b;
		return c/2 * (Math.sqrt(1 - (t-=2)*t) + 1) + b;
	},
	easeInElastic: function (x, t, b, c, d) {
		if (arguments.length === 1) {
			t = arguments[0]; x = 0; b = 0; c = 1; d = 1;
		}
		var s=1.70158;var p=0;var a=c;
		if (t==0) return b;  if ((t/=d)==1) return b+c;  if (!p) p=d*.3;
		if (a < Math.abs(c)) { a=c; var s=p/4; }
		else var s = p/(2*Math.PI) * Math.asin (c/a);
		return -(a*Math.pow(2,10*(t-=1)) * Math.sin( (t*d-s)*(2*Math.PI)/p )) + b;
	},
	easeOutElastic: function (x, t, b, c, d) {
		if (arguments.length === 1) {
			t = arguments[0]; x = 0; b = 0; c = 1; d = 1;
		}
		var s=1.70158;var p=0;var a=c;
		if (t==0) return b;  if ((t/=d)==1) return b+c;  if (!p) p=d*.3;
		if (a < Math.abs(c)) { a=c; var s=p/4; }
		else var s = p/(2*Math.PI) * Math.asin (c/a);
		return a*Math.pow(2,-10*t) * Math.sin( (t*d-s)*(2*Math.PI)/p ) + c + b;
	},
	easeInOutElastic: function (x, t, b, c, d) {
		if (arguments.length === 1) {
			t = arguments[0]; x = 0; b = 0; c = 1; d = 1;
		}
		var s=1.70158;var p=0;var a=c;
		if (t==0) return b;  if ((t/=d/2)==2) return b+c;  if (!p) p=d*(.3*1.5);
		if (a < Math.abs(c)) { a=c; var s=p/4; }
		else var s = p/(2*Math.PI) * Math.asin (c/a);
		if (t < 1) return -.5*(a*Math.pow(2,10*(t-=1)) * Math.sin( (t*d-s)*(2*Math.PI)/p )) + b;
		return a*Math.pow(2,-10*(t-=1)) * Math.sin( (t*d-s)*(2*Math.PI)/p )*.5 + c + b;
	},
	easeInBack: function (x, t, b, c, d) {
		if (arguments.length === 1) {
			t = arguments[0]; x = 0; b = 0; c = 1; d = 1;
		}
		if (s == undefined) s = 1.70158;
		return c*(t/=d)*t*((s+1)*t - s) + b;
	},
	easeOutBack: function (x, t, b, c, d) {
		if (arguments.length === 1) {
			t = arguments[0]; x = 0; b = 0; c = 1; d = 1;
		}
		if (s == undefined) s = 1.70158;
		return c*((t=t/d-1)*t*((s+1)*t + s) + 1) + b;
	},
	easeInOutBack: function (x, t, b, c, d) {
		if (arguments.length === 1) {
			t = arguments[0]; x = 0; b = 0; c = 1; d = 1;
		}
		if (s == undefined) s = 1.70158; 
		if ((t/=d/2) < 1) return c/2*(t*t*(((s*=(1.525))+1)*t - s)) + b;
		return c/2*((t-=2)*t*(((s*=(1.525))+1)*t + s) + 2) + b;
	},
	easeInBounce: function (x, t, b, c, d) {
		if (arguments.length === 1) {
			t = arguments[0]; x = 0; b = 0; c = 1; d = 1;
		}
		return c - Easing.easeOutBounce (x, d-t, 0, c, d) + b;
	},
	easeOutBounce: function (x, t, b, c, d) {
		if (arguments.length === 1) {
			t = arguments[0]; x = 0; b = 0; c = 1; d = 1;
		}
		if ((t/=d) < (1/2.75)) {
			return c*(7.5625*t*t) + b;
		} else if (t < (2/2.75)) {
			return c*(7.5625*(t-=(1.5/2.75))*t + .75) + b;
		} else if (t < (2.5/2.75)) {
			return c*(7.5625*(t-=(2.25/2.75))*t + .9375) + b;
		} else {
			return c*(7.5625*(t-=(2.625/2.75))*t + .984375) + b;
		}
	},
	easeInOutBounce: function (x, t, b, c, d) {
		if (arguments.length === 1) {
			t = arguments[0]; x = 0; b = 0; c = 1; d = 1;
		}
		if (t < d/2) return Easing.easeInBounce (x, t*2, 0, c, d) * .5 + b;
		return Easing.easeOutBounce (x, t*2-d, 0, c, d) * .5 + c*.5 + b;
	}
};

function getRandomInt(min, max) {
		return Math.floor(Math.random() * (max - min + 1)) + min;
}
function Tween ($config) {
	this.start = Date.now();
	this.duration = $config.duration;
	this.data = $config.data;
}
Tween.prototype.isFinished = function () {
	return Date.now() > this.start + this.duration;
};
Tween.prototype.getPercent = function () {
	return ((this.start + this.duration) - Date.now()) / this.duration; 
};

var canvas = document.createElement('canvas'),
	context = canvas.getContext('2d');

canvas.width = window.innerWidth;
canvas.height = window.innerHeight;

document.body.appendChild(canvas);

var tweens = [];

function draw () {
	requestAnimationFrame(draw);

	context.clearRect(0, 0, canvas.width, canvas.height);

	tweens.forEach(function (tween, index, array) {
		if (tween.isFinished()) {
			tweens.splice(tweens.indexOf(tween), 1);
		} else {
			var percent = Easing.easeInOutQuad(tween.getPercent()).toFixed(3),
				size = Math.floor((16 * tween.data.scale) * percent);
      
      		if (size < .5) return;
			
			context.font = size + 'px Arial';
			var text = tween.data.text;
      context.fillStyle = '#ff4742';

			context.fillText(text, (canvas.width/2 + ((percent) * tween.data.x) - (context.measureText(text).width/2)).toFixed(3), (canvas.height/2 + ((percent)  * tween.data.y) - (size/2)).toFixed(3));
			//context.fillRect((canvas.width/2 + ((percent) * tween.data.x) - (size/2)), (canvas.height/2 + ((percent)  * tween.data.y) - (size/2)), size, size);
		}
	});
}

function addParticle () {
  var x,
      y,
      scale = 1 + Math.random() * 3,
    side = getRandomInt(0, 3);

	if (side === 0) {
		// left
		x = -window.innerWidth/2 - 50;
		y = getRandomInt(-window.innerHeight/2 - 1, window.innerHeight/2 - 1);
	} else if (side === 1) {
		// top
		x = getRandomInt(-window.innerWidth/2 - 1, window.innerWidth/2 - 1);
		y = -window.innerHeight/2 - 50;
	} else if (side === 2) {
		// right
		x = window.innerWidth/2 + 50;
		y = getRandomInt(-window.innerHeight/2 - 1, window.innerHeight/2 - 1);
	} else if (side === 3) {
		// bottom
		x = getRandomInt(-window.innerWidth/2 - 1, window.innerWidth/2 - 1);
		y = window.innerHeight/2 + 50;
	}
  
  tweens.push(new Tween({
    duration: 800 + (Math.random() * 500),
    data: {x: x, y: y, scale: scale, text: 'hello'}
  }));
}


setInterval(function () {
  for (var i = 0; i < 10; i++) addParticle();
}, 200);
//addParticle();
draw();