anchor.diff:  
     final _projectionMatrix = new Matrix4.zero();
     final _viewMatrix = new Matrix4.identity();
  +  final _rotMatrix = new Matrix3.identity();
     final _projectionViewMatrix = new Matrix4.zero();
   
     updateProjectionMatrix() {
  
positive.code:     return b;
    }
  
    _setup(RenderingContext gl) {
      // Basic viewport setup and clearing of the screen
      gl.viewport(x, y, viewWidth, viewHeight);
  
negative.code: 
    updateViewMatrix() {
      setViewMatrix(_viewMatrix, position, focusPosition, upDirection);
      //_viewMatrix.getRotation()
      _rotMatrix.storage[0] = _viewMatrix.storage[0];
      _rotMatrix.storage[1] = _viewMatrix.storage[1];
      _rotMatrix.storage[2] = _viewMatrix.storage[2];
      _rotMatrix.storage[3] = _viewMatrix.storage[4];
      _rotMatrix.storage[4] = _viewMatrix.storage[5];
      _rotMatrix.storage[5] = _viewMatrix.storage[6];
      _rotMatrix.storage[6] = _viewMatrix.storage[8];
      _rotMatrix.storage[7] = _viewMatrix.storage[9];
      _rotMatrix.storage[8] = _viewMatrix.storage[10];
      updateProjectionViewMatrix();
    }
  
  