gistfile1.txt

// Add an event listener that fires the function onWindowResize on resize
window.addEventListener('resize', onWindowResize, false);

function onWindowResize() {
    // Adjust the camera aspect ratio to the camera to suit the new height and width of the window
    camera.aspect = window.innerWidth / window.innerHeight;

    // Updates the camera's projection matrix. (docs) 
    camera.updateProjectionMatrix();

    // Sets the size of the rendering viewport in which the camera fit in perfectly
    renderer.setSize(window.innerWidth, window.innerHeight);
}