MAYA-106486 Import UV set mappings #902
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Applies uvChooser nodes whenever the selected UV is not the default UV. Will merge specialized materials that were created on export solely to handle UV set names mismatches.
test/lib/usd/translators/UsdImportUVSetMappingsTest/UsdImportUVSetMappings.usda
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This overall looks good to me, but I'm not sure about the layer spelunking we're doing in _IsMergeableMaterial(). Am I missing something there? Can you help me understand why we're only considering the root layer? I would have thought we'd want to consider the fully composed stage instead.
| const PcpPrimIndex& primIndex = shadeMaterial.GetPrim().GetPrimIndex(); | ||
| PcpNodeRef primRoot = primIndex.GetRootNode(); | ||
| SdfPath primPath = primIndex.GetPath(); | ||
| const SdfLayerHandle& layer = primRoot.GetLayerStack()->GetLayerTree()->GetLayer(); |
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I'm not sure I understand why we're trying to find the root layer here. Don't we want to be considering the fully composed stage? Materials could be added or specialized, or opinions could be expressed, across multiple layers.
| } | ||
| }; | ||
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| layer->Traverse(primPath, testFunction); |
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Along the lines of the above comment, it seems like we'd want a stage-based traversal here rather than a layer-based one.
# Conflicts: # lib/usd/translators/shading/usdFileTextureWriter.cpp # lib/usd/translators/shading/usdUVTextureReader.cpp
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I think the SdfLayer::Traverse() currently at the bottom of _IsMergeableMaterial() could be replaced with something less expensive. We obviously can't assume that the USD we're importing came from Maya, so it seems very possible (and probably likely) that we might be importing a specialized material with potentially lots of scene description authored on or underneath it.
| UsdPrimCompositionQueryArc specializationArc = arcs[1]; | ||
| SdfPath primPath = shadeMaterial.GetPath(); | ||
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| // Check that the specialization arc contains only opinions on varname inputs: | ||
| bool retVal = true; | ||
| auto isVarnameOpinion = [&](const SdfPath& path) { | ||
| if (path == primPath) { | ||
| return; | ||
| } | ||
| if (path.GetParentPath() != primPath || !path.IsPrimPropertyPath()) { | ||
| retVal = false; | ||
| return; | ||
| } | ||
| std::vector<std::string> splitName = SdfPath::TokenizeIdentifier(path.GetName()); | ||
| // We allow only ["inputs", "<texture_name>", "varname"] | ||
| if (splitName.size() != 3 || splitName[0] != _tokens->inputs.GetString() | ||
| || splitName[2] != _tokens->varname.GetString()) { | ||
| retVal = false; | ||
| } | ||
| }; | ||
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| specializationArc.GetIntroducingLayer()->Traverse(primPath, isVarnameOpinion); |
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The layer-based traversal at the bottom here has the potential to be way more expensive than it needs to be. At the point where we start the traversal, all we know is that we're looking at a specialized material. The root of the traversal is the primSpec in the layer that introduced the specialize arc. That layer may also have an arbitrary number of properties and/or namespace children authored for that Material, and we're going to end up visiting all of those paths when really we know whether or not we should stop after inspecting only the Material primSpec and its properties.
With the caveat that this is untested, this is kind of what I'm thinking for this, beginning right after we verify that there are only two arcs:
// This is a little more robust than grabbing a specific arc index.
UsdPrimCompositionQuery::Filter filter;
filter.arcTypeFilter = UsdPrimCompositionQuery::ArcTypeFilter::Specialize;
query.SetFilter(filter);
arcs = query.GetCompositionArcs();
const UsdPrimCompositionQueryArc specializationArc = arcs.front();
const SdfLayerHandle layer = specializationArc.GetIntroducingLayer();
const SdfPrimSpecHandle primSpec = layer->GetPrimAtPath(shadeMaterial.GetPath());
// If the primSpec that specializes the base material introduces other
// namespace children, it can't be merged.
if (!primSpec->GetNameChildren().empty()) {
return false;
}
// Check that the only properties authored are varname inputs.
for (const SdfPropertySpecHandle& propSpec : primSpec->GetProperties()) {
const SdfPath propPath = propSpec->GetPath();
const std::vector<std::string> splitName =
SdfPath::TokenizeIdentifier(propPath.GetName());
// We allow only ["inputs", "<texture_name>", "varname"]
if (splitName.size() != 3u ||
splitName[0u] != _tokens->inputs.GetString() ||
splitName[2u] != _tokens->varname.GetString()) {
return false
}
}
return true;
JGamache-autodesk
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Applies uvChooser nodes whenever the selected UV is not the default UV.
Will merge specialized materials that were created on export solely to handle UV set names mismatches.