material {
  name: "SanctificationCardHolographic",
  shading_model: physical,
  blending: opaque,
  culling: back,
  parameters: [
    { type: sampler2d, name: artwork_texture, hint: default_white },
    { type: sampler2d, name: finish_mask_texture, hint: default_black },
    { type: vec3, name: light_position, default: [2.2, 2.5, 4.4] },
    { type: float, name: finish_strength, default: 0.6 },
    { type: float, name: roughness, default: 0.23 },
    { type: float, name: surface_detail, default: 0.14 },
  ],
}

fragment {
  vec3 Spectrum(float phase) {
    return 0.52 + 0.48 * cos(
      6.2831853 * (phase + vec3(0.0, 0.33, 0.67))
    );
  }

  float Hash(vec2 p) {
    return fract(sin(dot(p, vec2(127.1, 311.7))) * 43758.5453);
  }

  void Surface(inout MaterialInputs material) {
    vec2 uv = GetUV(0);
    vec3 artwork = SRGBToLinear(texture(artwork_texture, uv).rgb);
    float mask = texture(finish_mask_texture, uv).r;
    vec3 normal = GetWorldNormal();
    vec3 view_direction = GetViewDirection();
    vec3 light_direction = normalize(
      material_params.light_position - GetWorldPosition()
    );

    float paper = Hash(floor(uv * vec2(230.0, 322.0)));
    artwork *= 0.985 + (paper - 0.5) *
      material_params.surface_detail * 0.08;

    float view_phase = dot(view_direction, vec3(0.43, 0.24, 0.87));
    float light_phase = dot(light_direction, vec3(-0.31, 0.66, 0.68));
    float phase = uv.x * 1.7 + uv.y * 0.9 +
      view_phase * 0.78 + light_phase * 0.34;
    vec3 spectrum = Spectrum(phase);
    float grazing = pow(
      1.0 - clamp(dot(normal, view_direction), 0.0, 1.0),
      0.72
    );
    float coating = clamp(
      mask * material_params.finish_strength *
      (0.34 + grazing * 1.28),
      0.0,
      0.92
    );
    vec3 spectral_ink = artwork * mix(vec3(0.88), spectrum, 0.72);
    vec3 coated = mix(artwork, mix(artwork, spectral_ink, 0.48), coating);
    coated += spectrum * coating * grazing * 0.12;

    material.base_color = vec4(coated, 1.0);
    material.metallic = coating * 0.18;
    material.roughness = clamp(
      mix(max(material_params.roughness, 0.56), 0.22, coating),
      kMinRoughness,
      1.0
    );
    material.normal = normal;
    material.specular_weight = 1.0;
    material.specular_color = vec3(1.0);
    material.ior = 1.5;
    material.clearcoat = coating * 0.58;
    material.clearcoat_roughness = 0.24;
    material.clearcoat_normal = normal;
    material.iridescence = coating * 0.42;
    material.iridescence_ior = 1.3;
    material.iridescence_thickness = mix(180.0, 430.0, spectrum.r);
    PrepareMaterial(material);
  }
}