Method LoadParams

Hydrogent/src/HnMaterialNetwork.cpp:749–810

}

void HnMaterialNetwork::LoadParams(const pxr::HdMaterialNetwork2& Network,
                                   const pxr::HdMaterialNode2&    Node)
{
    // Hydrogent currently supports two material configurations.
    // A custom glslfx file or a PreviewSurface material network.
    // Either configuration consists of a terminal (Shader or PreviewSurface)
    // with its input values authored or connected to a primvar, texture or
    // volume node. The texture may have a primvar connected to provide UVs.
    //
    // The following code is made to process one of these two material configs
    // exclusively. It cannot convert arbitrary material networks by
    // generating the appropriate glsl code.

    pxr::SdrRegistry& ShaderReg = pxr::SdrRegistry::GetInstance();

    const pxr::SdrShaderNodeConstPtr SdrNode =
        ShaderReg.GetShaderNodeByIdentifierAndType(Node.nodeTypeId, pxr::HioGlslfxTokens->glslfx);

    if (SdrNode)
    {
        pxr::SdfPathSet VisitedNodes;
        for (const TfToken& InputName : SdrNode->GetInputNames())
        {
            ProcessInputParameter(Network, Node, InputName, VisitedNodes);
        }
    }
    else
    {
        LOG_WARNING_MESSAGE("Unrecognized node: ", Node.nodeTypeId.GetText());
    }

    // Set fallback values for the inputs on the terminal (excepting
    // referenced sampler coords).
    for (auto& Param : m_Parameters)
    {
        if (Param.Type != HnMaterialParameter::ParamType::AdditionalPrimvar &&
            Param.FallbackValue.IsEmpty())
        {
            Param.FallbackValue = GetParamFallbackValue(Network, Node, Param.Name);
        }
    }

    if (SdrNode)
    {
        // Create HnMaterialParameter for each primvar the terminal says it
        // needs.
        // Primvars come from 'attributes' in the glslfx and are separate from
        // the input 'parameters'. We need to create a material param for them
        // so that these primvars survive 'primvar filtering' that discards any
        // unused primvars on the mesh.
        // If the network lists additional primvars, we add those too.
        pxr::NdrTokenVec Primvars = SdrNode->GetPrimvars();
        Primvars.insert(Primvars.end(), Network.primvars.begin(), Network.primvars.end());
        std::sort(Primvars.begin(), Primvars.end());
        Primvars.erase(std::unique(Primvars.begin(), Primvars.end()), Primvars.end());

        for (const TfToken& PrimvarName : Primvars)
        {