code: public Matrix4 setToRotationScale (IMatrix3 rotScale) {
          return set(rotScale.m00(), rotScale.m01(), rotScale.m02(), 0f,
                     rotScale.m10(), rotScale.m11(), rotScale.m12(), 0f,
                     rotScale.m20(), rotScale.m21(), rotScale.m22(), 0f,
                     0, 0, 0, 1);
      }
docs: Sets this to a rotation plus scale matrix.
  
  @return a reference to this matrix, for chaining.