void
UsdImagingGprimAdapter::_DiscoverPrimvars(UsdGeomGprim const& gprim,
SdfPath const& cachePath,
UsdShadeShader const& shader,
UsdTimeCode time,
UsdImagingValueCache* valueCache)
{
// TODO: It might be convenient to implicitly wire up PtexFaceOffset and
// PtexFaceIndex primvars.
TF_DEBUG(USDIMAGING_SHADERS).Msg("\t Looking for <%s> primvars at <%s>\n",
gprim.GetPrim().GetPath().GetText(),
shader.GetPrim().GetPath().GetText());
for (UsdShadeParameter const& param : shader.GetParameters()) {
UsdShadeShader source;
TfToken outputName;
if (param.GetConnectedSource(&source, &outputName)) {
UsdAttribute attr = source.GetIdAttr();
TfToken id;
if (not attr or not attr.Get(&id)) {
continue;
}
TF_DEBUG(USDIMAGING_SHADERS).Msg("\t\t Param <%s> connected <%s>(%s)\n",
param.GetAttr().GetName().GetText(),
source.GetPath().GetText(),
id.GetText());
if (id == UsdHydraTokens->HwPrimvar_1) {
TfToken t;
VtValue v;
UsdGeomPrimvar primvarAttr;
if (UsdHydraPrimvar(source).GetVarnameAttr().Get(&t,
UsdTimeCode::Default())) {
primvarAttr = gprim.GetPrimvar(t);
if (primvarAttr.ComputeFlattened(&v, time)) {
TF_DEBUG(USDIMAGING_SHADERS).Msg("Found primvar %s\n",
t.GetText());
UsdImagingValueCache::PrimvarInfo primvar;
primvar.name = t;
primvar.interpolation = primvarAttr.GetInterpolation();
valueCache->GetPrimvar(cachePath, t) = v;
_MergePrimvar(primvar, &valueCache->GetPrimvars(cachePath));
} else {
TF_DEBUG(USDIMAGING_SHADERS).Msg(
"\t\t No primvar on <%s> named %s\n",
gprim.GetPath().GetText(),
t.GetText());
}
}
} else {
// Recursively look for more primvars
_DiscoverPrimvars(gprim, cachePath, source, time, valueCache);
}
}
}
}
// Walk the shader graph and emit nodes in topological order
// to avoid forward-references.
static
void _WalkGraph(UsdShadeShader const & shadeNode,
HdMaterialNetwork *materialNetwork,
const TfTokenVector &shaderSourceTypes)
{
// Store the path of the node
HdMaterialNode node;
node.path = shadeNode.GetPath();
if (!TF_VERIFY(node.path != SdfPath::EmptyPath())) {
return;
}
// If this node has already been found via another path, we do
// not need to add it again.
for (HdMaterialNode const& existingNode: materialNetwork->nodes) {
if (existingNode.path == node.path) {
return;
}
}
// Visit the inputs of this node to ensure they are emitted first.
const std::vector<UsdShadeInput> shadeNodeInputs = shadeNode.GetInputs();
for (UsdShadeInput const& input: shadeNodeInputs) {
// Check if this input is a connection and if so follow the path
UsdShadeConnectableAPI source;
TfToken sourceName;
UsdShadeAttributeType sourceType;
if (UsdShadeConnectableAPI::GetConnectedSource(input,
&source, &sourceName, &sourceType)) {
// When we find a connection to a shading node output,
// walk the upstream shading node. Do not do this for
// other sources (ex: a connection to a material
// public interface parameter), since they are not
// part of the shading node graph.
if (sourceType == UsdShadeAttributeType::Output) {
UsdShadeShader connectedNode(source);
_WalkGraph(connectedNode, materialNetwork, shaderSourceTypes);
}
}
}
// Extract the identifier of the node
TfToken id;
if (!shadeNode.GetShaderId(&id)) {
for (auto &sourceType : shaderSourceTypes) {
if (SdrShaderNodeConstPtr n =
shadeNode.GetShaderNodeForSourceType(sourceType)) {
id = n->GetIdentifier();
break;
}
}
}
if (!id.IsEmpty()) {
node.identifier = id;
// If a node is recognizable, we will try to extract the primvar
// names that is using since this can help render delegates
// optimize what what is needed from a prim when making data
// accessible for renderers.
_ExtractPrimvarsFromNode(shadeNode, node, materialNetwork);
} else {
TF_WARN("UsdShade Shader without an id: %s.", node.path.GetText());
node.identifier = TfToken("PbsNetworkMaterialStandIn_2");
}
// Add the parameters and the relationships of this node
VtValue value;
for (UsdShadeInput const& input: shadeNodeInputs) {
// Check if this input is a connection and if so follow the path
UsdShadeConnectableAPI source;
TfToken sourceName;
UsdShadeAttributeType sourceType;
if (UsdShadeConnectableAPI::GetConnectedSource(input,
&source, &sourceName, &sourceType)) {
if (sourceType == UsdShadeAttributeType::Output) {
// Store the relationship
HdMaterialRelationship relationship;
relationship.outputId = shadeNode.GetPath();
relationship.outputName = input.GetBaseName();
relationship.inputId = source.GetPath();
relationship.inputName = sourceName;
materialNetwork->relationships.push_back(relationship);
} else if (sourceType == UsdShadeAttributeType::Input) {
// Connected to an input on the public interface.
// The source is not a node in the shader network, so
// pull the value and pass it in as a parameter.
if (UsdShadeInput connectedInput =
source.GetInput(sourceName)) {
if (connectedInput.Get(&value)) {
node.parameters[input.GetBaseName()] = value;
}
}
}
} else {
// Parameters detected, let's store it
if (input.Get(&value)) {
node.parameters[input.GetBaseName()] = value;
}
}
}
materialNetwork->nodes.push_back(node);
}