static FnKat::Attribute
_GetMaterialAssignAttr(
const UsdPrim& prim,
const PxrUsdKatanaUsdInPrivateData& data)
{
if (not prim or prim.GetPath() == SdfPath::AbsoluteRootPath()) {
// Special-case to pre-empt coding errors.
return FnKat::Attribute();
}
UsdRelationship usdRel = UsdShadeLook::GetBindingRel(prim);
if (usdRel) {
// USD shading binding
SdfPathVector targetPaths;
usdRel.GetForwardedTargets(&targetPaths);
if (targetPaths.size() > 0) {
if (not targetPaths[0].IsPrimPath()) {
FnLogWarn("Target path " << prim.GetPath().GetString() <<
" is not a prim");
return FnKat::Attribute();
}
// This is a copy as it could be modified below.
SdfPath targetPath = targetPaths[0];
UsdPrim targetPrim = data.GetUsdInArgs()->GetStage()->GetPrimAtPath(targetPath);
// If the target is inside a master, then it needs to be re-targeted
// to the instance.
//
// XXX remove this special awareness once GetMasterWithContext is
// is available as the provided prim will automatically
// retarget (or provide enough context to retarget without
// tracking manually).
if (targetPrim and targetPrim.IsInMaster()) {
if (not data.GetInstancePath().IsEmpty() and
not data.GetMasterPath().IsEmpty()) {
// Check if the source and the target of the relationship
// belong to the same master.
// If they do, we have the context necessary to do the
// re-mapping.
if (data.GetMasterPath().GetCommonPrefix(targetPath).
GetPathElementCount() > 0) {
targetPath = data.GetInstancePath().AppendPath(
targetPath.ReplacePrefix(targetPath.GetPrefixes()[0],
SdfPath::ReflexiveRelativePath()));
} else {
// Warn saying the target of relationship isn't within
// the same master as the source.
FnLogWarn("Target path " << prim.GetPath().GetString()
<< " isn't within the master " << data.GetMasterPath());
return FnKat::Attribute();
}
} else {
// XXX
// When loading beneath a master via an isolatePath
// opArg, we can encounter targets which are within masters
// but not within the context of a material.
// While that would be an error according to the below
// warning, it produces the expected results.
// This case can occur when expanding pointinstancers as
// the sources are made via execution of PxrUsdIn again
// at the sub-trees.
// Warn saying target of relationship is in a master,
// but the associated instance path is unknown!
// FnLogWarn("Target path " << prim.GetPath().GetString()
// << " is within a master, but the associated "
// "instancePath is unknown.");
// return FnKat::Attribute();
}
}
// Convert the target path to the equivalent katana location.
// XXX: Looks may have an atypical USD->Katana
// path mapping
std::string location =
PxrUsdKatanaUtils::ConvertUsdLookPathToKatLocation(targetPath, data);
// XXX Looks containing only display terminals are causing issues
// with katana material manipulation workflows.
// For now: exclude any material assign which doesn't include
// /Looks/ in the path
if (location.find(UsdKatanaTokens->katanaLooksScopePathSubstring)
== std::string::npos)
{
return FnKat::Attribute();
}
// location = TfStringReplace(location, "/Looks/", "/Materials/");
// XXX handle multiple assignments
return FnKat::StringAttribute(location);
}
}
return FnKat::Attribute();
}
