code: function onWindowResize() {
        let threeD = document.getElementById('r3d');
        camera.canvas = {
          width: threeD.clientWidth,
          height: threeD.clientHeight,
        };
        camera.fitBox(2);
  
        renderer.setSize(threeD.clientWidth, threeD.clientHeight);
  
        // update info to draw borders properly
        stackHelper.slice.canvasWidth = threeD.clientWidth;
        stackHelper.slice.canvasHeight = threeD.clientHeight;
      }
docs: On window resize callback