Merge pull request #5424 from johnhaddon/collect

Collect : Add new node for collecting arbitrary values

Changes.md

@@ -5,6 +5,7 @@ Features
 --------
 
 - LightTool : Added manipulator for quad lights.
+- Collect : Added a utility node for collecting the values of arbitrary inputs across a range of contexts.
 
 Improvements
 ------------
@@ -21,11 +22,13 @@ Fixes
 - Arnold : Fixed screen window export for Lentil cameras.
 - Application : Fixed the `-threads` argument to clamp the number of threads to the number of available hardware cores (#5403).
 - CompareFloat, CompareColor, CompareVector : Worked around crashes in OSL's batched shading system (#5430).
+- PlugValueWidget : Fixed search for auxiliary plugs of output plugs. In this case, the inputs are now searched instead of the outputs.
 
 API
 ---
 
 - ThreadMonitor : Added new class for tracking the threads used to perform processes.
+- PlugAlgo : Added `findSource()` method.
 
 Documentation
 -------------

include/Gaffer/Collect.h

@@ -0,0 +1,119 @@
+//////////////////////////////////////////////////////////////////////////
+//
+//  Copyright (c) 2022, Cinesite VFX Ltd. All rights reserved.
+//
+//  Redistribution and use in source and binary forms, with or without
+//  modification, are permitted provided that the following conditions are
+//  met:
+//
+//      * Redistributions of source code must retain the above
+//        copyright notice, this list of conditions and the following
+//        disclaimer.
+//
+//      * Redistributions in binary form must reproduce the above
+//        copyright notice, this list of conditions and the following
+//        disclaimer in the documentation and/or other materials provided with
+//        the distribution.
+//
+//      * Neither the name of John Haddon nor the names of
+//        any other contributors to this software may be used to endorse or
+//        promote products derived from this software without specific prior
+//        written permission.
+//
+//  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
+//  IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
+//  THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+//  PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
+//  CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+//  EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+//  PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
+//  PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
+//  LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
+//  NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+//  SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+//
+//////////////////////////////////////////////////////////////////////////
+
+#pragma once
+
+#include "Gaffer/ComputeNode.h"
+#include "Gaffer/Export.h"
+#include "Gaffer/StringPlug.h"
+#include "Gaffer/TypedObjectPlug.h"
+#include "Gaffer/TypeIds.h"
+
+namespace Gaffer
+{
+
+class GAFFER_API Collect : public ComputeNode
+{
+
+	public :
+
+		Collect( const std::string &name = defaultName<Collect>() );
+		~Collect() override;
+
+		GAFFER_NODE_DECLARE_TYPE( Gaffer::Collect, CollectTypeId, ComputeNode );
+
+		StringPlug *contextVariablePlug();
+		const StringPlug *contextVariablePlug() const;
+
+		StringPlug *indexContextVariablePlug();
+		const StringPlug *indexContextVariablePlug() const;
+
+		StringVectorDataPlug *contextValuesPlug();
+		const StringVectorDataPlug *contextValuesPlug() const;
+
+		BoolPlug *enabledPlug() override;
+		const BoolPlug *enabledPlug() const override;
+
+		ValuePlug *inPlug();
+		const ValuePlug *inPlug() const;
+
+		ValuePlug *outPlug();
+		const ValuePlug *outPlug() const;
+
+		ObjectPlug *enabledValuesPlug();
+		const ObjectPlug *enabledValuesPlug() const;
+
+		bool canAddInput( const ValuePlug *prototype ) const;
+		ValuePlug *addInput( const ValuePlug *prototype );
+		void removeInput( ValuePlug *inputPlug );
+
+		ValuePlug *outputPlugForInput( const ValuePlug *inputPlug );
+		const ValuePlug *outputPlugForInput( const ValuePlug *inputPlug ) const;
+
+		ValuePlug *inputPlugForOutput( const ValuePlug *outputPlug );
+		const ValuePlug *inputPlugForOutput( const ValuePlug *outputPlug ) const;
+
+		void affects( const Plug *input, AffectedPlugsContainer &outputs ) const override;
+
+	protected :
+
+		void hash( const ValuePlug *output, const Context *context, IECore::MurmurHash &h ) const override;
+		void compute( ValuePlug *output, const Context *context) const override;
+
+		ValuePlug::CachePolicy hashCachePolicy( const ValuePlug *output ) const override;
+		ValuePlug::CachePolicy computeCachePolicy( const ValuePlug *output ) const override;
+
+	private :
+
+		// We collect the values for all output plugs in a single compute and cache
+		// them in a CompoundObject on this internal plug, indexing them by plug name.
+		// This provides greater ValuePlug cache coherency when multiple inputs depend
+		// on the same upstream computes (for instance, when they are each collecting
+		// a property of the same scene location).
+		CompoundObjectPlug *collectionPlug();
+		const CompoundObjectPlug *collectionPlug() const;
+
+		void inputAdded( GraphComponent *input );
+		void inputRemoved( GraphComponent *input );
+		void inputNameChanged( GraphComponent *input, IECore::InternedString oldName );
+
+		std::unordered_map<GraphComponent *, Signals::ScopedConnection> m_inputNameChangedConnections;
+
+		static size_t g_firstPlugIndex;
+
+};
+
+}  // namespace Gaffer

include/Gaffer/PlugAlgo.h

@@ -72,6 +72,11 @@ GAFFER_API bool dependsOnCompute( const ValuePlug *plug );
 template<typename Predicate>
 std::invoke_result_t<Predicate, Plug *> findDestination( Plug *plug, Predicate &&predicate );
 
+/// Visits the plug and its inputs, returing the first `predicate( plug )` result which
+/// evaluates to `true`.
+template<typename Predicate>
+std::invoke_result_t<Predicate, Plug *> findSource( Plug *plug, Predicate &&predicate );
+
 /// Conversion to and from `IECore::Data`
 /// =====================================
 

include/Gaffer/PlugAlgo.inl

@@ -84,4 +84,20 @@ std::invoke_result_t<Predicate, Plug *> findDestination( Plug *plug, Predicate &
 	return std::invoke_result_t<Predicate, Plug *>();
 }
 
+template<typename Predicate>
+std::invoke_result_t<Predicate, Plug *> findSource( Plug *plug, Predicate &&predicate )
+{
+	while( plug )
+	{
+		if( auto source = predicate( plug ) )
+		{
+			return source;
+		}
+		plug = plug->getInput();
+	}
+
+	// Typically a null pointer.
+	return std::invoke_result_t<Predicate, Plug *>();
+}
+
 } // namespace Gaffer::PlugAlgo

include/Gaffer/TypeIds.h

@@ -151,6 +151,7 @@ enum TypeId
 	HiddenFilePathFilterTypeId = 110105,
 	Color4fVectorDataPlugTypeId = 110106,
 	OptionalValuePlugTypeId = 110107,
+	CollectTypeId = 110108,
 
 	LastTypeId = 110159,