Rotate Vector by an angle
var rotateVector = function(vec, ang) { ang = -ang * (Math.PI/180); var cos = Math.cos(ang); var sin = Math.sin(ang); return new Array(Math.round(10000*(vec[0] * cos - vec[1] * sin))/10000, Math.round(10000*(vec[0] * sin + vec[1] * cos))/10000); };