USDMeshLight

Changes.md

@@ -9,6 +9,14 @@ Features
   - Prototypes and points that are editable downstream.
   - Export to USD.
   - Faster rendering.
+- USDMeshLight :
+  - Added node to add necessary attributes to geometry to convert to a USDMeshLight.
+  - Added Arnold, RenderMan, 3Delight and Cycles rendering.
+
+Improvements
+------------
+
+- MeshLight : Added viewport visualisation of textures.
 
 Fixes
 -----
@@ -292,6 +300,11 @@ Features
 - CopyFiles : Added node for copying files.
 - RenameFiles : Added node for renaming files.
 
+Improvements
+------------
+
+- MeshLight : Added viewport visualisation of textures.
+
 Fixes
 -----
 

include/GafferCycles/IECoreCyclesPreview/ShaderNetworkAlgo.h

@@ -96,6 +96,9 @@ IECORECYCLES_API IECoreScene::ShaderNetworkPtr convertLightShader( const IECoreS
 /// calling `convertLight()` and `convertLightShader()`.
 IECORECYCLES_API void convertUSDShaders( IECoreScene::ShaderNetwork *shaderNetwork );
 
+/// Returns a modified set of attributes conforming to the USDMeshLight specification.
+IECORECYCLES_API IECore::ConstCompoundObjectPtr convertUSDMeshLightAttributes( const IECore::CompoundObject *attributes );
+
 } // namespace ShaderNetworkAlgo
 
 } // namespace IECoreCycles

include/GafferSceneUI/Private/LightVisualiserAlgo.h

@@ -146,4 +146,6 @@ GAFFERSCENEUI_API void addWireframeCurveState( IECoreGL::Group *group, const flo
 /// made into a function that can be called by implementation shaders.
 GAFFERSCENEUI_API void addConstantShader( IECoreGL::Group *group, const Imath::Color3f &tint, int aimType = -1 );
 
+GAFFERSCENEUI_API void addTexturedConstantShader( IECoreGL::State *state, IECore::ConstDataPtr textureData, const Imath::Color3f &tint, const float saturation, const Imath::Color3f &gamma, int maxTextureResolution );
+
 }  // namespace GafferSceneUI::Private::LightVisualiserAlgo

include/GafferUSD/TypeIds.h

@@ -46,6 +46,7 @@ enum TypeId
 	USDAttributesTypeId = 119101,
 	USDShaderTypeId = 119102,
 	USDLightTypeId = 119103,
+	USDMeshLightTypeId = 119104,
 
 	LastTypeId = 119199
 

include/GafferUSD/USDMeshLight.h

@@ -0,0 +1,61 @@
+//////////////////////////////////////////////////////////////////////////
+//
+//  Copyright (c) 2026, 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 "GafferUSD/Export.h"
+#include "GafferUSD/TypeIds.h"
+
+#include "GafferScene/MeshLight.h"
+
+namespace GafferUSD
+{
+
+class GAFFERUSD_API USDMeshLight : public GafferScene::MeshLight
+{
+
+	public :
+
+		explicit USDMeshLight( const std::string &name=defaultName<USDMeshLight>() );
+		~USDMeshLight() override;
+
+		GAFFER_NODE_DECLARE_TYPE( GafferUSD::USDMeshLight, USDMeshLightTypeId, GafferScene::MeshLight );
+
+};
+
+IE_CORE_DECLAREPTR( USDMeshLight )
+
+} // namespace GafferUSD

include/IECoreArnold/ShaderNetworkAlgo.h

@@ -113,6 +113,9 @@ IECOREARNOLD_API void hashSubstitutions( const IECoreScene::ShaderNetwork *shade
 /// \deprecated Use `IECoreScene::ShaderNetworkAlgo::applyRenderAdaptors()` instead.
 IECOREARNOLD_API void applySubstitutions( IECoreScene::ShaderNetwork *shaderNetwork, IECore::InternedString attributeName, const IECore::CompoundObject *attributes );
 
+/// Returns a modified set of attributes conforming to the USDMeshLight specification.
+IECOREARNOLD_API IECore::ConstCompoundObjectPtr convertUSDMeshLightAttributes( const IECore::CompoundObject *attributes );
+
 } // namespace ShaderNetworkAlgo
 
 } // namespace IECoreArnold

include/IECoreDelight/ShaderNetworkAlgo.h

@@ -61,6 +61,9 @@ void updateLightGeometry( const IECoreScene::ShaderNetwork *shaderNetwork, NSICo
 /// tests.
 IECOREDELIGHT_API void convertUSDShaders( IECoreScene::ShaderNetwork *shaderNetwork );
 
+/// Returns a modified set of attributes conforming to the USDMeshLight specification.
+IECOREDELIGHT_API IECore::ConstCompoundObjectPtr convertUSDMeshLightAttributes( const IECore::CompoundObject *attributes );
+
 }  // namespace ShaderNetworkAlgo
 
 }  // namespace IECoreDelight

include/IECoreRenderMan/ShaderNetworkAlgo.h

@@ -84,4 +84,7 @@ IECORERENDERMAN_API VStructAction evaluateVStructConditional( const std::string
 /// as `convert()` resolves vstructs internally anyway.
 IECORERENDERMAN_API void resolveVStructs( IECoreScene::ShaderNetwork *shaderNetwork );
 
+/// Returns a modified set of attributes conforming to the USDMeshLight specification.
+IECORERENDERMAN_API IECore::ConstCompoundObjectPtr convertUSDMeshLightAttributes( const IECore::CompoundObject *attributes );
+
 } // namespace IECoreRenderMan::ShaderNetworkAlgo

python/GafferArnoldTest/ArnoldShaderTest.py

@@ -443,7 +443,7 @@ def testMeshLight( self ) :
 		self.assertEqual( n["type"].getValue(), "ai:light" )
 
 		self.assertTrue( "exposure" in n["parameters"] )
-		self.assertTrue( n["out"].typeId(), Gaffer.Plug.staticTypeId() )
+		self.assertEqual( n["out"].typeId(), Gaffer.Plug.staticTypeId() )
 
 	def testColorParameterMetadata( self ) :