package.fromRotation.js Maven / Gradle / Ivy
module.exports = fromRotation
/**
* Creates a matrix from a given angle around a given axis
* This is equivalent to (but much faster than):
*
* mat4.identity(dest)
* mat4.rotate(dest, dest, rad, axis)
*
* @param {mat4} out mat4 receiving operation result
* @param {Number} rad the angle to rotate the matrix by
* @param {vec3} axis the axis to rotate around
* @returns {mat4} out
*/
function fromRotation(out, rad, axis) {
var s, c, t
var x = axis[0]
var y = axis[1]
var z = axis[2]
var len = Math.sqrt(x * x + y * y + z * z)
if (Math.abs(len) < 0.000001) {
return null
}
len = 1 / len
x *= len
y *= len
z *= len
s = Math.sin(rad)
c = Math.cos(rad)
t = 1 - c
// Perform rotation-specific matrix multiplication
out[0] = x * x * t + c
out[1] = y * x * t + z * s
out[2] = z * x * t - y * s
out[3] = 0
out[4] = x * y * t - z * s
out[5] = y * y * t + c
out[6] = z * y * t + x * s
out[7] = 0
out[8] = x * z * t + y * s
out[9] = y * z * t - x * s
out[10] = z * z * t + c
out[11] = 0
out[12] = 0
out[13] = 0
out[14] = 0
out[15] = 1
return out
}