@thi.ng/vectors/rotate-around-axis.js

Optimized 2d/3d/4d and arbitrary length vector operations, support for memory mapping/layouts

import { setC3 } from "./setc.js";
const rotateAroundAxis3 = (out, v, axis, theta) => {
  const x = v[0];
  const y = v[1];
  const z = v[2];
  const ax = axis[0];
  const ay = axis[1];
  const az = axis[2];
  const ux = ax * x;
  const uy = ax * y;
  const uz = ax * z;
  const vx = ay * x;
  const vy = ay * y;
  const vz = ay * z;
  const wx = az * x;
  const wy = az * y;
  const wz = az * z;
  const uvw = ux + vy + wz;
  const s = Math.sin(theta);
  const c = Math.cos(theta);
  return setC3(
    out || v,
    ax * uvw + (x * (ay * ay + az * az) - ax * (vy + wz)) * c + (-wy + vz) * s,
    ay * uvw + (y * (ax * ax + az * az) - ay * (ux + wz)) * c + (wx - uz) * s,
    az * uvw + (z * (ax * ax + ay * ay) - az * (ux + vy)) * c + (-vx + uy) * s
  );
};
export {
  rotateAroundAxis3
};