package.rotateZ.js Maven / Gradle / Ivy
module.exports = rotateZ;
/**
* Rotates a matrix by the given angle around the Z axis
*
* @param {mat4} out the receiving matrix
* @param {mat4} a the matrix to rotate
* @param {Number} rad the angle to rotate the matrix by
* @returns {mat4} out
*/
function rotateZ(out, a, rad) {
var s = Math.sin(rad),
c = Math.cos(rad),
a00 = a[0],
a01 = a[1],
a02 = a[2],
a03 = a[3],
a10 = a[4],
a11 = a[5],
a12 = a[6],
a13 = a[7];
if (a !== out) { // If the source and destination differ, copy the unchanged last row
out[8] = a[8];
out[9] = a[9];
out[10] = a[10];
out[11] = a[11];
out[12] = a[12];
out[13] = a[13];
out[14] = a[14];
out[15] = a[15];
}
// Perform axis-specific matrix multiplication
out[0] = a00 * c + a10 * s;
out[1] = a01 * c + a11 * s;
out[2] = a02 * c + a12 * s;
out[3] = a03 * c + a13 * s;
out[4] = a10 * c - a00 * s;
out[5] = a11 * c - a01 * s;
out[6] = a12 * c - a02 * s;
out[7] = a13 * c - a03 * s;
return out;
};