point-geometry.js
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(function (root, factory){
if (typeof define === 'function' && define.amd){ // AMD
define(factory);
} else if (typeof module !== 'undefined' && module.exports) { // Node.js
module.exports = factory();
} else { // Browser
root.Point = factory();
}
})(this, function () {
function Point(x, y) {
this.x = x;
this.y = y;
}
Point.prototype = {
clone: function() { return new Point(this.x, this.y); },
add: function(p) { return this.clone()._add(p); },
sub: function(p) { return this.clone()._sub(p); },
mult: function(k) { return this.clone()._mult(k); },
div: function(k) { return this.clone()._div(k); },
rotate: function(a) { return this.clone()._rotate(a); },
matMult: function(m) { return this.clone()._matMult(m); },
unit: function() { return this.clone()._unit(); },
perp: function() { return this.clone()._perp(); },
round: function() { return this.clone()._round(); },
mag: function() {
return Math.sqrt(this.x * this.x + this.y * this.y);
},
equals: function(p) {
return this.x === p.x &&
this.y === p.y;
},
dist: function(p) {
return Math.sqrt(this.distSqr(p));
},
distSqr: function(p) {
var dx = p.x - this.x,
dy = p.y - this.y;
return dx * dx + dy * dy;
},
angle: function() {
return Math.atan2(this.y, this.x);
},
angleTo: function(b) {
return Math.atan2(this.y - b.y, this.x - b.x);
},
angleWith: function(b) {
return this.angleWithSep(b.x, b.y);
},
// Find the angle of the two vectors, solving the formula for the cross product a x b = |a||b|sin(θ) for θ.
angleWithSep: function(x, y) {
return Math.atan2(
this.x * y - this.y * x,
this.x * x + this.y * y);
},
_matMult: function(m) {
var x = m[0] * this.x + m[1] * this.y,
y = m[2] * this.x + m[3] * this.y;
this.x = x;
this.y = y;
return this;
},
_add: function(p) {
this.x += p.x;
this.y += p.y;
return this;
},
_sub: function(p) {
this.x -= p.x;
this.y -= p.y;
return this;
},
_mult: function(k) {
this.x *= k;
this.y *= k;
return this;
},
_div: function(k) {
this.x /= k;
this.y /= k;
return this;
},
_unit: function() {
this._div(this.mag());
return this;
},
_perp: function() {
var y = this.y;
this.y = this.x;
this.x = -y;
return this;
},
_rotate: function(angle) {
var cos = Math.cos(angle),
sin = Math.sin(angle),
x = cos * this.x - sin * this.y,
y = sin * this.x + cos * this.y;
this.x = x;
this.y = y;
return this;
},
_round: function() {
this.x = Math.round(this.x);
this.y = Math.round(this.y);
return this;
}
};
// constructs Point from an array if necessary
Point.convert = function (a) {
if (a instanceof Point) {
return a;
}
if (Array.isArray(a)) {
return new Point(a[0], a[1]);
}
return a;
};
return Point;
});