export default /* glsl */`
float G_BlinnPhong_Implicit( /* const in float dotNL, const in float dotNV */ ) {
// geometry term is (n dot l)(n dot v) / 4(n dot l)(n dot v)
return 0.25;
}
float D_BlinnPhong( const in float shininess, const in float dotNH ) {
return RECIPROCAL_PI * ( shininess * 0.5 + 1.0 ) * pow( dotNH, shininess );
}
vec3 BRDF_BlinnPhong( const in vec3 lightDir, const in vec3 viewDir, const in vec3 normal, const in vec3 specularColor, const in float shininess ) {
vec3 halfDir = normalize( lightDir + viewDir );
float dotNH = saturate( dot( normal, halfDir ) );
float dotVH = saturate( dot( viewDir, halfDir ) );
vec3 F = F_Schlick( specularColor, 1.0, dotVH );
float G = G_BlinnPhong_Implicit( /* dotNL, dotNV */ );
float D = D_BlinnPhong( shininess, dotNH );
return F * ( G * D );
} // validated
`;