Method MeshSplitter

src/IECoreScene/MeshAlgoSplit.cpp:336–447

} // namespace

IECoreScene::MeshAlgo::MeshSplitter::MeshSplitter( ConstMeshPrimitivePtr mesh, const PrimitiveVariable &segmentPrimitiveVariable, const IECore::Canceller *canceller ) : m_mesh( mesh ), m_segmentPrimitiveVariable( segmentPrimitiveVariable )
{
	if( segmentPrimitiveVariable.interpolation != IECoreScene::PrimitiveVariable::Interpolation::Uniform )
	{
		throw IECore::Exception( "Primitive variable passed to MeshSplitter must be uniform." );
	}

	if( !mesh->isPrimitiveVariableValid( segmentPrimitiveVariable ) )
	{
		throw IECore::Exception( "Primitive variable passed to MeshSplitter must be valid." );
	}

	const size_t numFaces = mesh->numFaces();
	if( numFaces == 0 )
	{
		// If we don't initialize anything, numMeshes() will return 0, meaning there is no valid context to
		// call mesh() in, which is correct for an empty mesh
		return;
	}

	int numSegments = 0;
	ConstIntVectorDataPtr faceToSegmentIndexData;
	std::vector<int> remapSegmentIndices;
	// remapSegmentIndexMin specifies the lowest value in the faceToSegmentIndexBuffer that we need to remap:
	// it shifts all accesses to the remapSegmentIndices, allowing remapSegmentIndices to be used when the
	// lowest element is not 0
	int remapSegmentIndexMin = 0;


	IECore::dispatch( segmentPrimitiveVariable.data.get(), [ segmentPrimitiveVariable, &numSegments, &faceToSegmentIndexData, &remapSegmentIndices, &remapSegmentIndexMin, canceller]( const auto *primVarData )
		{
			using DataType = typename std::remove_pointer_t< decltype( primVarData ) >;
			if constexpr ( !TypeTraits::IsVectorTypedData<DataType>::value )
			{
				throw IECore::Exception( "Invalid PrimitiveVariable, data is not a vector." );
			}
			else
			{
				initializeFaceToSegments< typename DataType::ValueType::value_type >(
					primVarData,
					segmentPrimitiveVariable.indices.get(),
					numSegments,
					faceToSegmentIndexData,
					remapSegmentIndices,
					remapSegmentIndexMin,
					canceller
				);
			}
		}
	);

	const std::vector<int> &faceToSegmentIndex = faceToSegmentIndexData->readable();

	// Now that we have our faceToSegmentIndex and remapSegmentIndices vector, we can count the number of faces
	// for each output mesh
	std::vector<int> faceCounts;
	faceCounts.resize( numSegments, 0 );