@thi.ng/matrices/frustum.js

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

import { DEG2RAD } from "@thi.ng/math/api";
import { setC } from "@thi.ng/vectors/setc";
const frustum = (out, left, right, bottom, top, near, far) => {
  const dx = 1 / (right - left);
  const dy = 1 / (top - bottom);
  const dz = 1 / (far - near);
  return setC(
    out || [],
    near * 2 * dx,
    0,
    0,
    0,
    0,
    near * 2 * dy,
    0,
    0,
    (right + left) * dx,
    (top + bottom) * dy,
    -(far + near) * dz,
    -1,
    0,
    0,
    -(far * near * 2) * dz,
    0
  );
};
const frustumBounds = (fovy, aspect, near, far) => {
  const top = near * Math.tan(fovy * DEG2RAD / 2);
  const right = top * aspect;
  return {
    left: -right,
    right,
    bottom: -top,
    top,
    near,
    far
  };
};
export {
  frustum,
  frustumBounds
};