float t(float minv, float maxv, float m) {
    float range = (maxv - minv);
    return (minv + range/2) + (range/2) * sin(iGlobalTime * m);
}
float pulse(float freq) {
    return 0.5 + 0.25 * sin(iGlobalTime * freq);
}
float getProceduralColors(inout vec3 diffuse, inout vec3 specular, inout float shininess) {
    diffuse = pulse(20.0) * vec3(1.0, 0.5, 0.8);
    diffuse = vec3(t(.5, 1, 5), t(.5, 1, 3), t(.5, 1, 2));
    //float size = 0.5 + (1 + sin(iGlobalTime * 2)) * 0.14;
    float size = 0.3;
    if (abs(_modelNormal.y) > size) {
        discard;
    }
    return 1.0;
}