How to invert the mouse press-and-drag in Babylon.js

Using the default playground as example (playground.babylonjs.com)

How can I invert the mouse press and drag directions?

var createScene = function () {
    var scene = new BABYLON.Scene(engine);

    var camera = new BABYLON.FreeCamera("camera1", new BABYLON.Vector3(0, 5, -10), scene);
    camera.setTarget(BABYLON.Vector3.Zero());   
    camera.attachControl(canvas, true);

    var light = new BABYLON.HemisphericLight("light", new BABYLON.Vector3(0, 1, 0), scene);   
    light.intensity = 0.7;

    var sphere = BABYLON.MeshBuilder.CreateSphere("sphere", {diameter: 2, segments: 32}, scene);    
    sphere.position.y = 1;

    var ground = BABYLON.MeshBuilder.CreateGround("ground", {width: 6, height: 6}, scene);

    return scene;
};

I was looking at the wrong documentation, it was there all the time:

camera.invertRotation = true;