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Support multiple glTF UV sets #2938

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Support multiple glTF UV sets #2938

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14 changes: 0 additions & 14 deletions source/MaterialXGraphEditor/RenderView.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -85,20 +85,6 @@ void applyModifiers(mx::DocumentPtr doc, const DocumentModifiers& modifiers)
}
}

// Remap unsupported texture coordinate indices.
for (mx::ElementPtr elem : doc->traverseTree())
{
mx::NodePtr node = elem->asA<mx::Node>();
if (node && node->getCategory() == "texcoord")
{
mx::InputPtr index = node->getInput("index");
mx::ValuePtr value = index ? index->getValue() : nullptr;
if (value && value->isA<int>() && value->asA<int>() != 0)
{
index->setValue(0);
}
}
}
}

void RenderView::setDocument(mx::DocumentPtr document)
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29 changes: 17 additions & 12 deletions source/MaterialXRender/CgltfLoader.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -270,9 +270,16 @@ bool CgltfLoader::load(const FilePath& filePath, MeshList& meshList, bool texcoo
{
continue;
}
// Only load one stream of each type for now.
cgltf_int streamIndex = attribute->index;
if (streamIndex != 0)

bool isPositionStream = (attribute->type == cgltf_attribute_type_position);
bool isNormalStream = (attribute->type == cgltf_attribute_type_normal);
bool isTangentStream = (attribute->type == cgltf_attribute_type_tangent);
bool isColorStream = (attribute->type == cgltf_attribute_type_color);
bool isTexCoordStream = (attribute->type == cgltf_attribute_type_texcoord);

// Only positions, normals, and tangents use the primary glTF stream.
if ((isPositionStream || isNormalStream || isTangentStream) && streamIndex != 0)
{
continue;
}
Expand All @@ -288,12 +295,6 @@ bool CgltfLoader::load(const FilePath& filePath, MeshList& meshList, bool texcoo

MeshStreamPtr geomStream = nullptr;

bool isPositionStream = (attribute->type == cgltf_attribute_type_position);
bool isNormalStream = (attribute->type == cgltf_attribute_type_normal);
bool isTangentStream = (attribute->type == cgltf_attribute_type_tangent);
bool isColorStream = (attribute->type == cgltf_attribute_type_color);
bool isTexCoordStream = (attribute->type == cgltf_attribute_type_texcoord);

if (isPositionStream)
{
// Create position stream
Expand Down Expand Up @@ -328,14 +329,18 @@ bool CgltfLoader::load(const FilePath& filePath, MeshList& meshList, bool texcoo
}
else if (isTexCoordStream)
{
texcoordStream = MeshStream::create("i_" + MeshStream::TEXCOORD_ATTRIBUTE + "_0", MeshStream::TEXCOORD_ATTRIBUTE, 0);
mesh->addStream(texcoordStream);
auto tcStream = MeshStream::create("i_" + MeshStream::TEXCOORD_ATTRIBUTE + "_" + std::to_string(streamIndex), MeshStream::TEXCOORD_ATTRIBUTE, streamIndex);
mesh->addStream(tcStream);
if (vectorSize == 2)
{
texcoordStream->setStride(MeshStream::STRIDE_2D);
tcStream->setStride(MeshStream::STRIDE_2D);
desiredVectorSize = 2;
}
geomStream = texcoordStream;
geomStream = tcStream;
if (streamIndex == 0)
{
texcoordStream = tcStream;
}
}
else
{
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10 changes: 9 additions & 1 deletion source/MaterialXRenderGlsl/GlslProgram.cpp
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Expand Up @@ -261,7 +261,15 @@ void GlslProgram::bindAttribute(const GlslProgram::InputMap& inputs, MeshPtr mes
MeshStreamPtr stream = mesh->getStream(input.first);
if (!stream)
{
throw ExceptionRenderError("Geometry buffer could not be retrieved for binding: " + input.first + ". Index: " + std::to_string(index));
// Fall back to the first texcoord stream when the mesh has fewer UV sets than the material.
if (input.first.find("i_texcoord_") != std::string::npos)

@jstone-lucasfilm jstone-lucasfilm Jun 7, 2026

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Perhaps we should use the existing constant HW::IN_TEXCOORD, rather than adding this hardcoded string? The same approach could be used in MSL and Slang as well.

{
stream = mesh->getStream(MeshStream::TEXCOORD_ATTRIBUTE, 0);
}
if (!stream)
{
throw ExceptionRenderError("Geometry buffer could not be retrieved for binding: " + input.first + ". Index: " + std::to_string(index));
}
}
MeshFloatBuffer& attributeData = stream->getData();
stride = stream->getStride();
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5 changes: 5 additions & 0 deletions source/MaterialXRenderMsl/MslPipelineStateObject.mm
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Expand Up @@ -369,6 +369,11 @@ int GetStrideOfMetalType(MTLDataType type)

unsigned int stride = 0;
MeshStreamPtr stream = mesh->getStream(input.first);
// Fall back to the first texcoord stream when the mesh has fewer UV sets than the material.

@jstone-lucasfilm jstone-lucasfilm Jun 7, 2026

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These two updates to GLSL and MSL look great, but I believe we need a corresponding update for Slang as well, in SlangProgram.cpp.

if (!stream && input.first.find("i_texcoord_") != std::string::npos)
{
stream = mesh->getStream(MeshStream::TEXCOORD_ATTRIBUTE, 0);
}
if (!stream)
{
errors.push_back("Geometry buffer could not be retrieved for binding: " + input.first + ". Index: " + std::to_string(index));
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14 changes: 0 additions & 14 deletions source/MaterialXView/Viewer.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -135,20 +135,6 @@ void applyModifiers(mx::DocumentPtr doc, const DocumentModifiers& modifiers)
}
}

// Remap unsupported texture coordinate indices.
for (mx::ElementPtr elem : doc->traverseTree())
{
mx::NodePtr node = elem->asA<mx::Node>();
if (node && node->getCategory() == "texcoord")
{
mx::InputPtr index = node->getInput("index");
mx::ValuePtr value = index ? index->getValue() : nullptr;
if (value && value->isA<int>() && value->asA<int>() != 0)
{
index->setValue(0);
}
}
}
}

} // anonymous namespace
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