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@Maksims
Created Mar 1, 2017
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pc.Angle = function(degrees) {
this._theta = (degrees * pc.Angle.RA) || 0;
this._normalize();
};
// constant to convert between radians and degrees
pc.Angle.RA = 180 / Math.PI;
pc.Angle.prototype = {
copy: function(angle) {
this._theta = angle._theta;
return this;
},
dot: function(angle) {
return this.x * angle.x + this.y * angle.y;
},
lerp: function(angle, speed) {
var d = this.distance(angle);
if (!d) return;
if (Math.abs(d) < speed) {
this._theta = angle._theta;
return this;
}
this._theta += Math.sign(d) * speed;
this._normalize();
return this;
},
distance: function(angle) {
var d = angle._theta - this._theta;
if (Math.abs(d) > Math.PI)
return (Math.PI2 - Math.abs(d)) * (-1 * Math.sign(d));
return d;
},
fromVec2: function(vec) {
if (!(vec instanceof Array))
vec = vec.data;
this._theta = Math.atan2(vec[0], vec[1]);
return this;
},
_normalize: function() {
this._theta -= Math.PI2 * Math.floor((this._theta + Math.PI) / Math.PI2);
return this;
}
};
Object.defineProperty(pc.Angle.prototype, 'radians', {
get: function() {
return this._theta;
},
set: function(value) {
this._theta = value;
this._normalize();
}
});
Object.defineProperty(pc.Angle.prototype, 'degrees', {
get: function() {
return this._theta * pc.Angle.RA;
},
set: function(value) {
this._theta = value / pc.Angle.RA;
this._normalize();
}
});
Object.defineProperty(pc.Angle.prototype, 'x', {
get: function() {
return Math.sin(this._theta);
}
});
Object.defineProperty(pc.Angle.prototype, 'y', {
get: function() {
return Math.cos(this._theta);
}
});
// pc.Vec2.fromAngle
pc.Vec2.prototype.fromAngle = function(angle) {
this.data[0] = Math.sin(angle._theta);
this.data[1] = Math.cos(angle._theta);
return this;
};
// Math.sign polyfill
Math.sign = Math.sign || function(x) {
if (x === 0 || isNaN(x))
return x;
return x > 0 ? 1 : -1;
};
// Math.PI2
Math.PI2 = Math.PI * 2;
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