anchor.diff:      _transformMatrixBoxToNode.invert();
   
       return _transformMatrixBoxToNode;
  +  }
  +
  +  Matrix4 _inverseMatrix() {
  +    if (_transformMatrixInverse == null) {
  +      _transformMatrixInverse = new Matrix4.copy(transformMatrix);
  +      _transformMatrixInverse.invert();
  +    }
  +    return _transformMatrixInverse;
     }
   
     /// Converts a point from the coordinate system of the [SpriteBox] to the local coordinate system of the node.
  
positive.code:   double _rotation = 0.0;
  
    Matrix4 _transformMatrix = new Matrix4.identity();
    Matrix4 _transformMatrixNodeToBox;
    Matrix4 _transformMatrixBoxToNode;
  
  
negative.code:   /// changes that affects the matrix.
    void invalidateTransformMatrix() {
      _transformMatrix = null;
      _transformMatrixInverse = null;
      _invalidateToBoxTransformMatrix();
    }
  
  