C++ UsdRelationship::AddTarget方法代码示例

void
UsdRiStatementsAPI::SetCoordinateSystem(const std::string &coordSysName)
{
    UsdAttribute attr = GetPrim().CreateAttribute(_tokens->coordsys, 
                                                  SdfValueTypeNames->String, 
                                                  /* custom = */ false);
    if (TF_VERIFY(attr)) {
        attr.Set(coordSysName);

        UsdPrim currPrim = GetPrim();
        while (currPrim && currPrim.GetPath() != SdfPath::AbsoluteRootPath()) {
            if (currPrim.IsModel() && !currPrim.IsGroup() &&
                currPrim.GetPath() != SdfPath::AbsoluteRootPath()) {
                UsdRelationship rel =
                    currPrim.CreateRelationship(_tokens->modelCoordsys,
                                                /* custom = */ false);
                if (TF_VERIFY(rel)) {
                    // Order should not matter, since these are a set,
                    // but historically we have appended these.
                    rel.AddTarget(GetPrim().GetPath());
                }
                break;
            }

            currPrim = currPrim.GetParent();
        }
    }
}

bool
PxrUsdTranslators_InstancerWriter::writeInstancerAttrs(
        const UsdTimeCode& usdTime,
        const UsdGeomPointInstancer& instancer)
{
    MStatus status = MS::kSuccess;
    MFnDagNode dagNode(GetDagPath(), &status);
    CHECK_MSTATUS_AND_RETURN(status, false);

    // Note: In this function, we don't read instances using the provided
    // MFnInstancer API. One reason is that it breaks up prototypes into their
    // constituent shapes, and there's no way to figure out which hierarchy
    // they came from. Another reason is that it only provides computed matrices
    // and not separate position, rotation, scale attrs.

    const SdfPath prototypesGroupPath =
            instancer.GetPrim().GetPath().AppendChild(_tokens->Prototypes);

    // At the default time, setup all the prototype instances.
    if (usdTime.IsDefault()) {
        const MPlug inputHierarchy = dagNode.findPlug("inputHierarchy", true,
                &status);
        CHECK_MSTATUS_AND_RETURN(status, false);

        // Note that the "Prototypes" prim needs to be a model group to ensure
        // contiguous model hierarchy.
        const UsdPrim prototypesGroupPrim = GetUsdStage()->DefinePrim(
                prototypesGroupPath);
        UsdModelAPI(prototypesGroupPrim).SetKind(KindTokens->group);
        _modelPaths.push_back(prototypesGroupPath);

        UsdRelationship prototypesRel = instancer.CreatePrototypesRel();

        const unsigned int numElements = inputHierarchy.numElements();
        for (unsigned int i = 0; i < numElements; ++i) {
            const MPlug plug = inputHierarchy[i];
            const MPlug source(UsdMayaUtil::GetConnected(plug));
            if (source.isNull()) {
                TF_WARN("Cannot read prototype: the source plug %s was null",
                        plug.name().asChar());
                return false;
            }

            MFnDagNode sourceNode(source.node(), &status);
            CHECK_MSTATUS_AND_RETURN(status, false);

            MDagPath prototypeDagPath;
            sourceNode.getPath(prototypeDagPath);

            // Prototype names are guaranteed unique by virtue of having a
            // unique numerical suffix _# indicating the prototype index.
            const TfToken prototypeName(
                    TfStringPrintf("%s_%d", sourceNode.name().asChar(), i));
            const SdfPath prototypeUsdPath = prototypesGroupPrim.GetPath()
                    .AppendChild(prototypeName);
            UsdPrim prototypePrim = GetUsdStage()->DefinePrim(
                    prototypeUsdPath);
            _modelPaths.push_back(prototypeUsdPath);

            // Try to be conservative and only create an intermediary xformOp
            // with the instancerTranslate if we can ensure that we don't need
            // to compensate for the translation on the prototype root.
            //
            // XXX: instancerTranslate does not behave well when added to a
            // reference that has an existing transform on the far side of the
            // reference. However, its behavior at least matches the
            // behavior in UsdMayaTranslatorModelAssembly. If we fix the
            // behavior there, we need to make sure that this is also
            // fixed to match.
            bool instancerTranslateAnimated = false;
            if (_NeedsExtraInstancerTranslate(
                    prototypeDagPath, &instancerTranslateAnimated)) {
                UsdGeomXformable xformable(prototypePrim);
                UsdGeomXformOp newOp = xformable.AddTranslateOp(
                        UsdGeomXformOp::PrecisionDouble,
                        _tokens->instancerTranslate);
                _instancerTranslateOps.push_back(
                        {prototypeDagPath, newOp, instancerTranslateAnimated});
            }

            // Two notes:
            // (1) We don't un-instance here, because it's OK for the prototype
            // to just be a reference to an instance master if the prototype
            // participates in Maya native instancing.
            // (2) The prototype root must be visible to match Maya's behavior,
            // which always vis'es the prototype root, even if it is marked
            // hidden.
            _writeJobCtx.CreatePrimWriterHierarchy(
                    prototypeDagPath,
                    prototypeUsdPath,
                    /*forceUninstance*/ false,
                    /*exportRootVisibility*/ false,
                    &_prototypeWriters);
            prototypesRel.AddTarget(prototypeUsdPath);
        }

        _numPrototypes = numElements;
    }

    // If there aren't any prototypes, fail and don't export on subsequent
//.........这里部分代码省略.........