message: handle Vec3.angle edge case
diff: @@ -474,7 +474,9 @@ namespace Vec3 {
  /** Computes the angle between 2 vectors, reports in radians. */
  export function angle(a: Vec3, b: Vec3) {
  - const theta = dot(a, b) / Math.sqrt(squaredMagnitude(a) * squaredMagnitude(b));
  + const denominator = Math.sqrt(squaredMagnitude(a) * squaredMagnitude(b));
  + if (denominator === 0) return Math.PI / 2;
  + const theta = dot(a, b) / denominator;
  return Math.acos(clamp(theta, -1, 1)); // clamp to avoid numerical problems
  }
  