export declare const apply_interior_color = "\nif (interior) {\n    material.rgb = mix(material.rgb, uInteriorColor.rgb, uInteriorColor.a);\n\n    float isf = clamp(uInteriorSubstance.a, 0.0, 0.99); // clamp to avoid artifacts\n    metalness = mix(metalness, uInteriorSubstance.r, isf);\n    roughness = mix(roughness, uInteriorSubstance.g, isf);\n    bumpiness = mix(bumpiness, uInteriorSubstance.b, isf);\n\n    #ifdef dTransparentBackfaces_opaque\n        material.a = 1.0;\n    #endif\n}\n";