static bool
_GatherRibAttributes(
const UsdPrim &prim,
double currentTime,
FnKat::GroupBuilder& attrsBuilder)
{
bool hasAttrs = false;
// USD SHADING STYLE ATTRIBUTES
UsdRiStatements riStatements(prim);
if (riStatements) {
const std::vector<UsdProperty> props =
riStatements.GetRiAttributes();
std::string attrName;
TF_FOR_ALL(propItr, props) {
UsdProperty prop = *propItr;
if (!prop) continue;
std::string nameSpace =
riStatements.GetRiAttributeNameSpace(prop).GetString();
nameSpace = TfStringReplace(nameSpace, ":", ".") + ".";
attrName = nameSpace +
riStatements.GetRiAttributeName(prop).GetString();
VtValue vtValue;
UsdAttribute usdAttr = prim.GetAttribute(prop.GetName());
if (usdAttr) {
if (not usdAttr.Get(&vtValue, currentTime))
continue;
// XXX asShaderParam really means:
// "For arrays, as a single attr vs a type/value pair group"
// The type/value pair group is meaningful for attrs who don't
// have a formal type definition -- like a "user" RiAttribute.
//
// However, other array values (such as two-element shadingrate)
// are not expecting the type/value pair form and will not
// generate rib correctly. As such, we'll handle the "user"
// attribute as a special case.
bool asShaderParam = true;
if (nameSpace == "user.")
{
asShaderParam = false;
}
attrsBuilder.set(attrName, PxrUsdKatanaUtils::ConvertVtValueToKatAttr(vtValue,
asShaderParam) );
}
else {
UsdRelationship usdRel = prim.GetRelationship(prop.GetName());
attrsBuilder.set(attrName, PxrUsdKatanaUtils::ConvertRelTargetsToKatAttr(usdRel,
/* asShaderParam */ false) );
}
hasAttrs = true;
}
}
/* static */
UsdAttribute PxrUsdMayaWriteUtil::GetOrCreateUsdRiAttribute(
const MPlug& attrPlug,
const UsdPrim& usdPrim,
const std::string& attrName,
const std::string& nameSpace,
const bool translateMayaDoubleToUsdSinglePrecision)
{
UsdAttribute usdAttr;
if (!usdPrim) {
return usdAttr;
}
MObject attrObj(attrPlug.attribute());
TfToken riAttrNameToken(attrName);
if (riAttrNameToken.IsEmpty()) {
MGlobal::displayError(
TfStringPrintf("Invalid UsdRi attribute name '%s' for Maya plug '%s'",
attrName.c_str(),
attrPlug.name().asChar()).c_str());
return usdAttr;
}
UsdRiStatements riStatements(usdPrim);
if (!riStatements) {
return usdAttr;
}
// See if a UsdRi attribute with this name already exists. If so, return it.
// XXX: There isn't currently API for looking for a specific UsdRi attribute
// by name, so we have to get them all and then see if one matches.
const std::vector<UsdProperty>& riAttrs = riStatements.GetRiAttributes(nameSpace);
TF_FOR_ALL(iter, riAttrs) {
if (iter->GetBaseName() == riAttrNameToken) {
// Re-get the attribute from the prim so we can return it as a
// UsdAttribute rather than a UsdProperty.
return usdPrim.GetAttribute(iter->GetName());
}
}
const SdfValueTypeName& typeName =
PxrUsdMayaWriteUtil::GetUsdTypeName(attrPlug,
translateMayaDoubleToUsdSinglePrecision);
if (typeName) {
usdAttr = riStatements.CreateRiAttribute(riAttrNameToken,
typeName.GetType(),
nameSpace);
}
return usdAttr;
}
