inline half calculateBRDF(in SurfaceData data, in half NdotH, in half LdotH)
{
    half d = NdotH * NdotH * data.roughness2MinusOne + 1.00001h;

    half LdotH2 = LdotH * LdotH;
    half specularTerm = data.roughness2 / ((d * d) * max(0.1h, LdotH2) * data.normalizationTerm);

    return specularTerm;
}

inline half3 applyBRDF(in SurfaceData data, in half3 lightPos, in half3 lightColor)
{
    half3 L = normalize(lightPos);
    half3 H = normalize(data.view + L);

    half NdotH = saturate(dot(data.normal, H));
    half LdotH = saturate(dot(L, H));

    half3 radiance = lightColor * diffuse(L, data.normal);
    half brdf = calculateBRDF(data, NdotH, LdotH);

    return (brdf * data.specular + data.diffuse) * radiance;
}