code: public Planed frustumPlane(int which, Planed plane) {
          switch (which) {
          case PLANE_NX:
              plane.set(m00, m10, m20, 1.0 + m30).normalize(plane);
              break;
          case PLANE_PX:
              plane.set(-m00, -m10, -m20, 1.0 - m30).normalize(plane);
              break;
          case PLANE_NY:
              plane.set(m01, m11, m21, 1.0 + m31).normalize(plane);
              break;
          case PLANE_PY:
              plane.set(-m01, -m11, -m21, 1.0 - m31).normalize(plane);
              break;
          case PLANE_NZ:
              plane.set(m02, m12, m22, 1.0 + m32).normalize(plane);
              break;
          case PLANE_PZ:
              plane.set(-m02, -m12, -m22, 1.0 - m32).normalize(plane);
              break;
          default:
              throw new IllegalArgumentException("which"); //$NON-NLS-1$
          }
          return plane;
      }
docs: /* (non-Javadoc)
  @see org.joml.Matrix4x3dc#frustumPlane(int, org.joml.Planed)