23 lines
416 B
JavaScript
23 lines
416 B
JavaScript
|
module.exports = rotate
|
||
|
|
|
||
|
|
/**
|
||
|
|
* Rotates a vec2 by an angle
|
||
|
|
*
|
||
|
|
* @param {vec2} out the receiving vector
|
||
|
|
* @param {vec2} a the vector to rotate
|
||
|
|
* @param {Number} angle the angle of rotation (in radians)
|
||
|
|
* @returns {vec2} out
|
||
|
|
*/
|
||
|
|
function rotate(out, a, angle) {
|
||
|
|
var c = Math.cos(angle),
|
||
|
|
s = Math.sin(angle)
|
||
|
|
var x = a[0],
|
||
|
|
y = a[1]
|
||
|
|
|
||
|
|
out[0] = x * c - y * s
|
||
|
|
out[1] = x * s + y * c
|
||
|
|
|
||
|
|
return out
|
||
|
|
}
|
||
|
|
|