Merge pull request #5612 from GafferHQ/arnoldIntegralTypeFix

Arnold Renderer : Fix translation of `uchar` data from USD

Changes.md

@@ -10,6 +10,11 @@ Improvements
 - USDLight : Added file browser for `shaping:ies:file` parameter.
 - OpenColorIOContext : Added file browser for `config` plug.
 
+Fixes
+-----
+
+- Arnold : Fixed translation of USD `uchar` attributes and shader parameters.
+
 API
 ---
 

python/IECoreArnoldTest/RendererTest.py

@@ -1254,6 +1254,36 @@ def testSubdivisionAttributes( self ) :
 			self.assertEqual( arnold.AiNodeGetStr( node, "subdiv_adaptive_space" ), "raster" )
 			self.assertEqual( arnold.AiNodeGetBool( node, "subdiv_frustum_ignore" ), True )
 
+	def testUCharSubdivIterations( self ) :
+
+		r = GafferScene.Private.IECoreScenePreview.Renderer.create(
+			"Arnold",
+			GafferScene.Private.IECoreScenePreview.Renderer.RenderType.SceneDescription,
+			str( self.temporaryDirectory() / "test.ass" )
+		)
+
+		subdivPlane = IECoreScene.MeshPrimitive.createPlane( imath.Box2f( imath.V2f( -1 ), imath.V2f( 1 ) ) )
+		subdivPlane.interpolation = "catmullClark"
+
+		r.object(
+			"plane",
+			subdivPlane,
+			r.attributes(
+				IECore.CompoundObject( {
+					"ai:polymesh:subdiv_iterations" : IECore.UCharData( 10 ),
+				} )
+			)
+		)
+
+		r.render()
+		del r
+
+		with IECoreArnold.UniverseBlock( writable = True ) as universe :
+
+			arnold.AiSceneLoad( universe, str( self.temporaryDirectory() / "test.ass" ), None )
+			node = arnold.AiNodeGetPtr( arnold.AiNodeLookUpByName( universe, "plane" ), "node" )
+			self.assertEqual( arnold.AiNodeGetByte( node, "subdiv_iterations" ), 10 )
+
 	def testSSSSetNameAttribute( self ) :
 
 		r = GafferScene.Private.IECoreScenePreview.Renderer.create(

python/IECoreArnoldTest/ShaderNetworkAlgoTest.py

@@ -184,6 +184,32 @@ def assertNoiseAndFlatNodes() :
 				ctypes.addressof( nodes[0].contents )
 			)
 
+	def testUCharParameters( self ) :
+
+		for dataType in ( IECore.IntData, IECore.UCharData ) :
+
+			with self.subTest( dataType = dataType ) :
+
+				network = IECoreScene.ShaderNetwork(
+					shaders = {
+						"imageHandle" : IECoreScene.Shader(
+							"image", "surface",
+							{
+								"start_channel" : dataType( 10 ),
+							}
+						),
+					},
+					output = "imageHandle"
+				)
+
+				with IECoreArnold.UniverseBlock( writable = True ) as universe :
+
+					nodes = IECoreArnold.ShaderNetworkAlgo.convert( network, universe, "test" )
+
+					self.assertEqual( len( nodes ), 1 )
+					self.assertEqual( arnold.AiNodeEntryGetName( arnold.AiNodeGetNodeEntry( nodes[0] ) ), "image" )
+					self.assertEqual( arnold.AiNodeGetByte( nodes[0], "start_channel" ), 10 )
+
 	def testBlindData( self ) :
 
 		flat = IECoreScene.Shader( "flat" )

src/IECoreArnold/ParameterAlgo.cpp

@@ -107,7 +107,11 @@ void setParameterInternal( AtNode *node, AtString name, int parameterType, bool
 				}
 				break;
 			case AI_TYPE_BYTE :
-				if( const IntData *data = dataCast<IntData>( name, value ) )
+				if( const IntData *data = runTimeCast<const IntData>( value ) )
+				{
+					AiNodeSetByte( node, name, data->readable() );
+				}
+				else if( const UCharData *data = dataCast<UCharData>( name, value ) )
 				{
 					AiNodeSetByte( node, name, data->readable() );
 				}

src/IECoreArnold/Renderer.cpp

@@ -1537,7 +1537,7 @@ class ArnoldAttributes : public IECoreScenePreview::Renderer::AttributesInterfac
 
 			PolyMesh( const IECore::CompoundObject *attributes )
 			{
-				subdivIterations = attributeValue<int>( g_polyMeshSubdivIterationsAttributeName, attributes, 1 );
+				subdivIterations = integralAttribute<uint8_t>( g_polyMeshSubdivIterationsAttributeName, attributes, 1 );
 				subdivAdaptiveError = attributeValue<float>( g_polyMeshSubdivAdaptiveErrorAttributeName, attributes, 0.0f );
 
 				const IECore::StringData *subdivAdaptiveMetricData = attribute<IECore::StringData>( g_polyMeshSubdivAdaptiveMetricAttributeName, attributes );
@@ -1574,7 +1574,7 @@ class ArnoldAttributes : public IECoreScenePreview::Renderer::AttributesInterfac
 				subdivFrustumIgnore = attributeValue<bool>( g_polyMeshSubdivFrustumIgnoreAttributeName, attributes, false );
 			}
 
-			int subdivIterations;
+			uint8_t subdivIterations;
 			float subdivAdaptiveError;
 			AtString subdivAdaptiveMetric;
 			AtString subdivAdaptiveSpace;
@@ -1902,6 +1902,37 @@ class ArnoldAttributes : public IECoreScenePreview::Renderer::AttributesInterfac
 			return defaultValue;
 		}
 
+		template<typename T>
+		static T integralAttribute( const IECore::InternedString &name, const IECore::CompoundObject *attributes, T defaultValue )
+		{
+			IECore::CompoundObject::ObjectMap::const_iterator it = attributes->members().find( name );
+			if( it == attributes->members().end() )
+			{
+				return defaultValue;
+			}
+
+			if constexpr( !std::is_same_v<T, int> )
+			{
+				// Gaffer currently uses IntData for all integral attributes regardless of the
+				// actual type in Arnold, so first check for that.
+				/// \todo Produce the expected types in Gaffer.
+				if( auto intData = IECore::runTimeCast<const IECore::IntData>( it->second.get() ) )
+				{
+					return intData->readable();
+				}
+			}
+
+			// Data coming from USD will use the exact Arnold type - for instance `unsigned char`
+			// for `subdiv_iterations`.
+			using DataType = IECore::TypedData<T>;
+			if( auto sd = reportedCast<const DataType>( it->second.get(), "attribute", name ) )
+			{
+				return sd->readable();
+			};
+
+			return defaultValue;
+		}
+
 		static void updateVisibility( unsigned char &visibility, const IECore::InternedString &name, unsigned char rayType, const IECore::CompoundObject *attributes )
 		{
 			if( const IECore::BoolData *d = attribute<IECore::BoolData>( name, attributes ) )