ghtAmbient: [0.3, 0.7, 0.4],
            lightDiffuse: [1.0, 1.0, 1.0],
            lightSpecular: [1.0, 1.0, 1.0],
            lightDirection: [-1, -1, 1]
        };
        const shader = new reshader.PhongShader({
            positionAttribute: 'POSITION',
            normalAttribute: 'NORMAL',
            extraCommandProps: {
                viewport
            }
        });

        const geometryShader = new reshader.MeshShader({
            vert: polygonVert,
            frag: polygonFrag,
         