OnEvaluate()

void PBRMaterialNode::OnEvaluate ( GLSLFunction *  function, GLSLLine *  line  )

overridevirtual

Implements SNENode.

Definition at line 38 of file PBRMaterialNode.cpp.

{
    LoadPBRFunctions(handler);
    function->AddLine(GLSLLine("vec3 " + VAR("albedo") + " = vec3(1.0f);", "The albedo color of the material."));
    function->AddLine(GLSLLine("vec3 " + VAR("normal") + " = vec3(1.0f);", "The normal of the material."));
    function->AddLine(GLSLLine("float " + VAR("metallic") + " = 1.0f;", "The metalic of the material."));
    function->AddLine(GLSLLine("float " + VAR("roughness") + " = 1.0f;", "The roughness of the material."));
    function->AddLine(GLSLLine("float " + VAR("ao") + " = 1.0f;", "The ambient occlusion of the material."));
 
    if(inputPins[0]->IsLinked())
    {
        GLSLLine tmp("", "");
        inputPins[0]->other->Evaluate(GetParams(function, &tmp));
        function->AddLine(GLSLLine("if(" + SDATA(0) + " == 1.0f)", "If gamma corection is enabled adjust the texture accordingly."));
        function->AddLine(GLSLLine("\t" + VAR("albedo") + " = pow(" + tmp.line + ", vec3(gamma));", "The albedo color of the material."));
        function->AddLine(GLSLLine("else", "If gamma corection is disabled just use the texture as it is."));
        function->AddLine(GLSLLine("\t" + VAR("albedo") + " = " + tmp.line + ";", "The albedo color of the material."));
    }
 
    if(inputPins[1]->IsLinked())
    {
        GLSLLine tmp("", "");
        inputPins[1]->other->Evaluate(GetParams(function, &tmp));
        function->AddLine(GLSLLine(VAR("normal") + " = " + tmp.line + ";", "The normal map sampled for current fragment"));
        function->AddLine(GLSLLine(VAR("normal") + " = TBN * (" + VAR("normal") + " * 2.0f - 1.0f);", "Scale the normal to -1.0f to 1.0f and transform to tangent space"));
    }
 
    if(inputPins[5]->IsLinked())
    {
        GLSLLine tmp("", "");
        inputPins[5]->other->Evaluate(GetParams(function, &tmp));
        function->AddLine(GLSLLine("", "Using the ARM texture for ao, roughness and metalic"));
        function->AddLine(GLSLLine("vec3 " + VAR("tmp") + " = " + tmp.line + ";", "Temporatily storing the arm data."));
        function->AddLine(GLSLLine(VAR("ao") + " = " + VAR("tmp") + ".x;", "The ambient occlusion of the material."));
        function->AddLine(GLSLLine(VAR("roughness") + " = " + VAR("tmp") + ".y;", "The roughness of the material."));
        function->AddLine(GLSLLine(VAR("metallic") + " = " + VAR("tmp") + ".z;", "The metalic of the material."));
    }
 
    else
    {
        if(inputPins[2]->IsLinked())
        {
            GLSLLine tmp("", "");
            inputPins[2]->other->Evaluate(GetParams(function, &tmp));
            function->AddLine(GLSLLine(VAR("metallic") + " = " + tmp.line + ".x;", "The metalic of the material."));
        }
 
        if(inputPins[3]->IsLinked())
        {
            GLSLLine tmp("", "");
            inputPins[3]->other->Evaluate(GetParams(function, &tmp));
            function->AddLine(GLSLLine(VAR("roughness") + " = " + tmp.line + ".x;", "The roughness of the material."));
        }
 
        if(inputPins[4]->IsLinked())
        {
            GLSLLine tmp("", "");
            inputPins[4]->other->Evaluate(GetParams(function, &tmp));
            function->AddLine(GLSLLine(VAR("ao") + " = " + tmp.line + ".x;", "The ambient occlusion of the material."));
        }
    }
 
    function->AddLine(GLSLLine("vec3 " + VAR("N") + " = " + VAR("normal") + ";", "The normal vector"));
    function->AddLine(GLSLLine("vec3 " + VAR("V") + " = normalize(_CameraPos - FragPos.xyz);", "The view vector"));
    function->AddLine(GLSLLine("", ""));
    function->AddLine(GLSLLine("", "Calculate reflectance at normal incidence; if dia-electric (like plastic) use F0"));
    function->AddLine(GLSLLine("", "of 0.04 and if it's a metal, use the albedo color as F0 (metallic workflow)"));
    function->AddLine(GLSLLine("vec3 " + VAR("F0") + " = vec3(0.04f);", ""));
    function->AddLine(GLSLLine(VAR("F0") + " = mix(" + VAR("F0") + ", " + VAR("albedo") + ", " + VAR("metallic") + " );", ""));
    function->AddLine(GLSLLine("", "Reflectance equation"));
    function->AddLine(GLSLLine("vec3 " + VAR("Lo") + " = vec3(0.0f);", ""));
    function->AddLine(GLSLLine("// for(int i = 0 ; i < _NumLights ; i++ )", ""));
    function->AddLine(GLSLLine("// {", ""));
    function->AddLine(GLSLLine("", "Calculate per-light radiance"));
    function->AddLine(GLSLLine("vec3 " + VAR("L") + " = normalize(_LightPosition - FragPos.xyz);", ""));
    function->AddLine(GLSLLine("vec3 " + VAR("H") + " = normalize(" + VAR("V") + " + " + VAR("L") + ");", ""));
    function->AddLine(GLSLLine("float " + VAR("distance") + " = length( _LightPosition - FragPos.xyz );", ""));
    function->AddLine(GLSLLine("float " + VAR("attenuation") + " = 1.0f / (" + VAR("distance") + " * " + VAR("distance") + ");", ""));
    function->AddLine(GLSLLine("vec3  " + VAR("radiance") + " = _LightColor * _LightStrength * " + VAR("attenuation") + ";", ""));
    function->AddLine(GLSLLine("", ""));
    function->AddLine(GLSLLine("", "Color-Torrance BRDF"));
    function->AddLine(GLSLLine("float " + VAR("NDF") + " = DistributionGGX(" + VAR("N") + ", " + VAR("H") + ", " + VAR("roughness") + ");", ""));
    function->AddLine(GLSLLine("float " + VAR("G") + " = GeometrySmith(" + VAR("N") + ", " + VAR("V") + ", " + VAR("L") + ", " + VAR("roughness") + ");", ""));
    function->AddLine(GLSLLine("vec3 " + VAR("F") + " = fresnelSchlick(max(dot(" + VAR("H") + ", " + VAR("V") + "), 0.0f), " + VAR("F0") + ");", ""));
    function->AddLine(GLSLLine("", ""));
    function->AddLine(GLSLLine("vec3 " + VAR("numerator") + " = " + VAR("NDF") + " * " + VAR("G") + " * " + VAR("F") + ";", ""));
    function->AddLine(GLSLLine("float " + VAR("denominator") + " = 4.0f * max(dot(" + VAR("N") + ", " + VAR("V") + "), 0.0f) * max(dot(" + VAR("N") + ", " + VAR("L") + "), 0.0f) + 0.0001f;", "+ 0.0001f to prevent divide by zero"));
    function->AddLine(GLSLLine("vec3 " + VAR("specular") + " = " + VAR("numerator") + " / " + VAR("denominator") + ";", ""));
    function->AddLine(GLSLLine("", ""));
    function->AddLine(GLSLLine("vec3 " + VAR("kS") + " = " + VAR("F") + ";", "kS is equal to Fresnel"));
    function->AddLine(GLSLLine("", ""));
    function->AddLine(GLSLLine("", "For energy conservation, the diffuse and specular light can't"));
    function->AddLine(GLSLLine("", "be above 1.0 (unless the surface emits light); to preserve this"));
    function->AddLine(GLSLLine("", "relationship the diffuse component (kD) should equal 1.0 - kS."));
    function->AddLine(GLSLLine("vec3 " + VAR("kD") + " = vec3(1.0f) - " + VAR("kS") + ";", ""));
    function->AddLine(GLSLLine("", ""));
    function->AddLine(GLSLLine("", "Multiply kD by the inverse metalness such that only non-metals"));
    function->AddLine(GLSLLine("", "have diffuse lighting, or a linear blend if partly metal (pure metals"));
    function->AddLine(GLSLLine("", "have no diffuse light)."));
    function->AddLine(GLSLLine(VAR("kD") + " *= 1.0 - " + VAR("metallic") + ";", ""));
    function->AddLine(GLSLLine("", ""));
    function->AddLine(GLSLLine("", "Scale light by NdotL"));
    function->AddLine(GLSLLine("float " + VAR("NdotL") + " = max(dot(" + VAR("N") + ", " + VAR("L") + "), 0.0f); ", ""));
    function->AddLine(GLSLLine("", ""));
    function->AddLine(GLSLLine("", "// Add to outgoing radiance Lo"));
    function->AddLine(GLSLLine(VAR("Lo") + " += (" + VAR("kD") + " * " + VAR("albedo") + " / PI + " + VAR("specular") + ") * " + VAR("radiance") + " * " + VAR("NdotL") + ";", "Note that we already multiplied the BRDF by the Fresnel (kS) so we won't multiply by kS again"));
    function->AddLine(GLSLLine("", ""));
    function->AddLine(GLSLLine("// }", ""));
    function->AddLine(GLSLLine("", ""));
    function->AddLine(GLSLLine("", "Ambient lighting (note that the next IBL tutorial will replace"));
    function->AddLine(GLSLLine("", "this ambient lighting with environment lighting)."));
    function->AddLine(GLSLLine("vec3 " + VAR("ambient") + " = vec3(0.03f) * " + VAR("albedo") + " * " + VAR("ao") + ";", ""));
    function->AddLine(GLSLLine("", ""));
    function->AddLine(GLSLLine("vec3 " + VAR("result") + " = " + VAR("ambient") + " + " + VAR("Lo") + ";", ""));
    function->AddLine(GLSLLine("", ""));
    function->AddLine(GLSLLine("if(" + SDATA(1) + " == 1.0f)", "If HDR Tonemapping is enable tonemap the result"));
    function->AddLine(GLSLLine("{", ""));
    function->AddLine(GLSLLine("\t" + VAR("result") + " = " + VAR("result") + " / (" + VAR("result") + " + vec3(1.0f));", ""));
    function->AddLine(GLSLLine("}", ""));
    function->AddLine(GLSLLine("", ""));
    function->AddLine(GLSLLine("if(" + SDATA(0) + " == 1.0f)", "If Gamma Correction is enable gamma correct the result"));
    function->AddLine(GLSLLine("{", ""));
    function->AddLine(GLSLLine("\t" + VAR("result") + " = pow(" + VAR("result") + ", vec3(1.0f/gamma));", ""));
    function->AddLine(GLSLLine("}", ""));
    function->AddLine(GLSLLine("", ""));
    line->line = VAR("result");
}