/////////////////////////////

        // create atToolkitContext
        const arToolkitContext = new ArToolkitContext({
            detectionMode: 'mono',
            canvasWidth: 480,
            canvasHeight: 640,
        }, {
            sourceWidth: 480,
            sourceHeight: 640,
        })

        // initialize it
        arToolkitContext.init(function onCompleted(){
            // copy projection matrix to camera
            camera.projectionMatrix.copy( arToolkitContext.getProjectionMatrix() 