vec2

vec2.js

var bbb = {};

bbb.extend = function(dst, src) {
	for(var key in src) if(src.hasOwnProperty(key)) dst[key] = src[key];
	return dst;
};

bbb.math = {};

var vec2 = (function() {
	function vec2(v) {
		bbb.extend(this, {
			x: v.x,
			y: v.y,
		});
	};
	
	function is_vec2(v) { return v instanceof vec2; };

	bbb.extend(vec2, {
		isVec2: is_vec2,
		add: function(v, w) { return new vec2(v.x + w.x, v.y + w.y); },
		sub: function(v, w) { return new vec2(v.x - w.x, v.y - w.y); },
		mul: function(v, s) { return new vec2(v.x * s, v.y * s); },
		div: function(v, s) { return new vec2(v.x / s, v.y / s); },
		eq: function(v, w) { return v.x == w.x && v.y == w.y; },
		neq: function(v, w) { return v.x != w.x || v.y != w.y; },
		dot: function(v, w) { return v.x * w.x + v.y * w.y; },
		cross: function(w, w) { return v.x * w.y - v.y * w.x; },
		abs: function(v) { return v.x * v.x + v.y * v.y; },
		length: function(v) { return Math.sqrt(v.x * v.x + v.y * v.y); },
		lerp: function(v, w, t) { var s = 1.0 - t; return new vec2(s * v.x + t * w.x, s * v.y + t * w.y); },
		create: function(x, y) { return new vec2(is_vec2(x) ? x : {x: x, y: y}); },
		cast: function(x, y) { return is_vec2(x) ? x : {x: x, y: y}; },
	});
	
	bbb.extend(vec2.prototype, {
		clone: function() { return new vec2(this); },
		eq: function(v) { return this.x == v.x && this.y == v.y; },
		translate: function(v) {
			this.x += v.x;
			this.y += v.y;
			return this;
		},
		translated: function(v) { return this.clone().translate(this.x + v.x, this.y + v.y); },
		scale: function(sx, sy) {
			this.x *= sx;
			this.y *= sy === undefined ? sx : sy;
			return this;
		},
		scaled: function(sx, sy) { return this.clone().scale(sx, sy); },
		reflct: function() { return this.scale(-1.0); },
		reflected: function() { return this.scaled(-1.0); },
		rotate: function(rad) {
			var c = Math.cos(rad),
				s = Math.sin(rad),
				x = c * this.x + s * this.y,
				y = -s * this.y + c * this.x;
			this.x = x;
			this.y = y;
			return this;
		},
		rotated: function(rad) { return this.clone().rotate(rad); },
		rotateTo: function(rad) {
			var len = this.length();
			this.x = Math.cos(rad) * len;
			this.y = Math.sin(rad) * len;
			return this;
		},
		rotatedTo: function(rad) { this.clone().rotateTo(rad); },
		length: function() { return Math.sqrt(this.x * this.x + this.y + this.y); },
		interpolate: function(v, t) {
			var s = 1.0 - t;
			this.x = s * this.x + t * v.x;
			this.y = s * this.y + t * v.y;
			return this;
		},
		interpolated: function(v, t) { return this.clone().interpolated(v, t); },
		middle: function(v) { return this.interpolate(v, 0.5); },
		middled: function(v) { return this.clone().interpolate(v, 0.5); },
		normalize: function(v) {
			var l = 1.0 / this.length();
			this.x *= l;
			this.y *= l;
			return this;
		},
		normalized: function(v) { this.clone().normalize(v); },
		distance: function(v) { return v.reflected().translate(v).length(); },
		dot: function(v) { return this.x * v.x + this.y * v.y; },
		cross: function(v) { return this.x * v.y + this.y * v.x; },
		angle: function() { return Math.atan(this.y, this.x); },
		angleTo: function(v) { return v.reflected().translate(this).angle(); },
		toString: function() { return "(" + this.x + ", " + this.y + ")"; },
	});
	return vec2;
})();

bbb.extend(bbb.math, {
	vec2: vec2
});