/**
 * Struct for representing a material for a {@link Model}. The model
 * rendering pipeline will pass this struct between material, custom shaders,
 * and lighting stages. This is not to be confused with {@link czm_material}
 * which is used by the older Fabric materials system, although they are similar.
 * <p>
 * All color values (diffuse, specular, emissive) are in linear color space.
 * </p>
 *
 * @name czm_modelMaterial
 * @glslStruct
 *
 * @property {vec4} baseColor The base color of the material.
 * @property {vec3} diffuse Incoming light that scatters evenly in all directions.
 * @property {float} alpha Alpha of this material. 0.0 is completely transparent; 1.0 is completely opaque.
 * @property {vec3} specular Color of reflected light at normal incidence in PBR materials. This is sometimes referred to as f0 in the literature.
 * @property {float} roughness A number from 0.0 to 1.0 representing how rough the surface is. Values near 0.0 produce glossy surfaces, while values near 1.0 produce rough surfaces.
 * @property {vec3} normalEC Surface's normal in eye coordinates. It is used for effects such as normal mapping. The default is the surface's unmodified normal.
 * @property {float} occlusion Ambient occlusion recieved at this point on the material. 1.0 means fully lit, 0.0 means fully occluded.
 * @property {vec3} emissive Light emitted by the material equally in all directions. The default is vec3(0.0), which emits no light.
 */
struct czm_modelMaterial {
    vec4 baseColor;
    vec3 diffuse;
    float alpha;
    vec3 specular;
    float roughness;
    vec3 normalEC;
    float occlusion;
    vec3 emissive;
#ifdef USE_SPECULAR
    float specularWeight;
#endif
#ifdef USE_ANISOTROPY
    vec3 anisotropicT;
    vec3 anisotropicB;
    float anisotropyStrength;
#endif
#ifdef USE_CLEARCOAT
    float clearcoatFactor;
    float clearcoatRoughness;
    vec3 clearcoatNormal;
    // Add clearcoatF0 when KHR_materials_ior is implemented
#endif
};