@thi.ng/matrices/lookat.js

Matrix & quaternion operations for 2D/3D geometry processing

import { cross3 } from "@thi.ng/vectors/cross";
import { dot3 } from "@thi.ng/vectors/dot";
import { normalize3 } from "@thi.ng/vectors/normalize";
import { setC } from "@thi.ng/vectors/setc";
import { sub3 } from "@thi.ng/vectors/sub";
const lookAt = (out, eye, target, up) => {
  const z = normalize3(null, sub3([], eye, target));
  const x = normalize3(null, cross3([], up, z));
  const y = normalize3(null, cross3([], z, x));
  return setC(
    out || [],
    x[0],
    y[0],
    z[0],
    0,
    x[1],
    y[1],
    z[1],
    0,
    x[2],
    y[2],
    z[2],
    0,
    -dot3(eye, x),
    -dot3(eye, y),
    -dot3(eye, z),
    1
  );
};
export {
  lookAt
};