                 source: `
                                uniform vec4 color;
                                uniform float cellAlpha;
                                czm_material czm_getMaterial(czm_materialInput materialInput)
                                {
                                    czm_material material = czm_getDefaultMaterial(materialInput);
                                    vec2 st = materialInput.st;
                                    float aa = st.s * st.t;
                 