/**
	Easing functions for various usage

		var coord = window.ease.sineOut(time, 0, 1);
		myDom.style.left = 500 * coord + "px";

	@method ease
	@for window

	@param {Number} t The time value while being eased
	@param {Number} c The start value to be eased from
	@param {Number} b The destination value to ease
	
	@return {Number} Result value
**/

window.ease = (function() {
	var PI = Math.PI, PIH = PI * 0.5;

	return {
		linear: function(t, c, b) {
			return b * t + c;
		},
		backIn: function(t, c, b) {
			return b * t * t * (2.70158 * t - 1.70158) + c;
		},
		backOut: function(t, c, b) {
			t -= 1;
			return b * ( t * t * (2.70158 * t + 1.70158) + 1) + c;
		},
		backInOut: function(t, c, b) {
			t *= 2;

			if (t < 1) {
				return 0.5 * b * t * t * (3.5949095 * t - 2.5949095) + c;
			} else {
				t -= 2;
				return 0.5 * b * (t * t * (3.70158 * t + 2.70158) + 2) + c;
			}
		},
		bounceOut: function(t, c, b) {
			if (t < 0.363636) {
				return 7.5625 * b * t * t + c;
			} else if (t < 0.727272) {
				t -= 0.545454;
				return b * (7.5625 * t * t + 0.75) + c;
			} else if (t < 0.90909) {
				t -= 0.818181;
				return b * (7.5625 * t * t + 0.9375) + c;
			} else {
				t -= 0.95454;
				return b * (7.5625 * t * t + 0.984375) + c;
			}
		},
		sineIn: function(t, c, b) {
			return -b * Math.cos(t * PIH) + b + c;
		},
		sineOut: function(t, c, b) {
			return b * Math.sin(t * PIH) + c;
		},
		sineInOut: function(t, c, b) {
			return 0.5 * -b * (Math.cos(PI * t) - 1) + c;
		},
		circleIn: function(t, c, b) {
			return -b * (Math.sqrt(1 - t * t) - 1) + c;
		},
		circleOut: function(t, c, b) {
			t -= 1;
			return b * Math.sqrt(1 - t * t) + c;
		},
		circleInOut: function(t, c, b) {
			t *= 2;
			if (t < 1) {
				return 0.5 * -b * (Math.sqrt(1 - t * t) - 1) + c;
			} else {
				t -= 2;
				return 0.5 * b * (Math.sqrt(1 - t * t) + 1) + c;
			}
		},
		quadraticIn: function(t, c, b) {
			return b * t * t + c;
		},
		quadraticOut: function(t, c, b) {
			return -b * t * (t - 2) + c;
		}
	};
})();