setRotationFromQuaternion method

Mat3 setRotationFromQuaternion(Quaternion q)

Set the matrix from a quaterion

Implementation

Mat3 setRotationFromQuaternion(Quaternion q){
  final x = q.x;
  final y = q.y;
  final z = q.z;
  final w = q.w;
  final x2 = x + x;
  final y2 = y + y;
  final z2 = z + z;
  final xx = x * x2;
  final xy = x * y2;
  final xz = x * z2;
  final yy = y * y2;
  final yz = y * z2;
  final zz = z * z2;
  final wx = w * x2;
  final wy = w * y2;
  final wz = w * z2;
  List<double> e = elements;

  e[3 * 0 + 0] = 1 - (yy + zz);
  e[3 * 0 + 1] = xy - wz;
  e[3 * 0 + 2] = xz + wy;

  e[3 * 1 + 0] = xy + wz;
  e[3 * 1 + 1] = 1 - (xx + zz);
  e[3 * 1 + 2] = yz - wx;

  e[3 * 2 + 0] = xz - wy;
  e[3 * 2 + 1] = yz + wx;
  e[3 * 2 + 2] = 1 - (xx + yy);

  return this;
}