window.addEventListener("keydown", function(e){
        switch( e.keyCode ) {
            case 37:	// vinstri ör
                mv1 = mult( mv, translate(-1.0, 0.0, 0.0));
                mv2 = mult( mv, translate(-1.0, 0.0, 0.0));
                mv3 = mult( mv, translate(-1.0, 0.0, 0.0));
                console.log("vinstri");
                //teikna(mv1, mv2, mv3);
                break;
            case 39:	// hægri ör
                mv1 = mult( mv, translate(1.0, 0.0, 0.0));
                mv2 = mult( mv, translate(1.0, 0.0, 0.0));
                mv3 = mult( mv, translate(1.0, 0.0, 0.0));
                console.log("hægri");
                //teikna(mv1, mv2, mv3);
                break;
            case 38: // upp
                mv1 = mult( mv, translate(0.0, 0.0, 1.0));
                mv2 = mult( mv, translate(0.0, 0.0, 1.0));
                mv3 = mult( mv, translate(0.0, 0.0, 1.0));
                console.log("upp");
                //teikna(mv1, mv2, mv3);
                break;
            case 40: // niður
                mv1 = mult( mv, translate(0.0, 0.0, -1.0));
                mv2 = mult( mv, translate(0.0, 0.0, -1.0));
                mv3 = mult( mv, translate(0.0, 0.0, -1.0));
                console.log("niður");
                //teikna(mv1, mv2, mv3);
                break;
            default:
                break;

        }
        gl.uniformMatrix4fv(matrixLoc, false, flatten(mv1));
        gl.drawArrays( gl.LINES, 0, numVertices );
        gl.uniformMatrix4fv(matrixLoc, false, flatten(mv2));
        gl.drawArrays( gl.LINES, 0, numVertices );
        gl.uniformMatrix4fv(matrixLoc, false, flatten(mv3));
        gl.drawArrays( gl.LINES, 0, numVertices );

    } );