OSL Image Sampler Prototype Update

SConstruct

@@ -1040,6 +1040,24 @@ cyclesDefines = [
 	( "WITH_OPTIX" ),
 ]
 
+cyclesLibraries = [
+	"cycles_session", "cycles_scene", "cycles_graph", "cycles_bvh", "cycles_device", "cycles_kernel", "cycles_kernel_osl",
+	"cycles_integrator", "cycles_util", "cycles_subd", "extern_sky", "extern_cuew"
+]
+
+# It's very weird to link the Cycles static libraries twice, to both
+# lib/libGafferCycles.so and python/GafferCycles/_GafferCycles.so, resulting in 2 copies of everything.
+# This has caused issues on Ubuntu where the init stuff cycles_session runs twice, terminating Gaffer with an
+# exception when the node buffer_pass is registered twice. It seems to work fine on Linux if we don't double
+# link it - the symbols from the static library can be included just in libGafferCycles, and the dynamic linker
+# will find them OK.
+# But on Windows, it seems the symbols from the static libraries aren't made available in libGafferCycles, so
+# it wouldn't work to just link them once. It is currently unknown why Windows doesn't have problems with
+# running the initialization in cycles_session twice.
+# Hopefully this hackery works for now - we're hoping in the long run, Cycles might ship as a dynamic lib, which
+# would simplify all this.
+includeCyclesLibrariesInPythonModule = env["PLATFORM"] == "win32"
+
 libraries = {
 
 	"Gaffer" : {
@@ -1350,9 +1368,8 @@ libraries = {
 			"LIBPATH" : [ "$CYCLES_ROOT/lib" ],
 			"LIBS" : [
 				"IECoreScene$CORTEX_LIB_SUFFIX", "IECoreImage$CORTEX_LIB_SUFFIX", "IECoreVDB$CORTEX_LIB_SUFFIX",
-				"Gaffer", "GafferScene", "GafferDispatch", "GafferOSL",
-				"cycles_session", "cycles_scene", "cycles_graph", "cycles_bvh", "cycles_device", "cycles_kernel", "cycles_kernel_osl",
-				"cycles_integrator", "cycles_util", "cycles_subd", "extern_sky", "extern_cuew",
+				"Gaffer", "GafferScene", "GafferDispatch", "GafferOSL"
+			] + cyclesLibraries + [
 				"OpenImageIO$OIIO_LIB_SUFFIX", "OpenImageIO_Util$OIIO_LIB_SUFFIX", "oslexec$OSL_LIB_SUFFIX", "oslquery$OSL_LIB_SUFFIX",
 				"openvdb$VDB_LIB_SUFFIX", "Alembic", "osdCPU", "OpenColorIO$OCIO_LIB_SUFFIX", "embree4", "Iex", "openpgl",
 			],
@@ -1364,8 +1381,7 @@ libraries = {
 			"LIBPATH" : [ "$CYCLES_ROOT/lib" ],
 			"LIBS" : [
 				"Gaffer", "GafferScene", "GafferDispatch", "GafferBindings", "GafferCycles", "IECoreScene",
-				"cycles_session", "cycles_scene", "cycles_graph", "cycles_bvh", "cycles_device", "cycles_kernel", "cycles_kernel_osl",
-				"cycles_integrator", "cycles_util", "cycles_subd", "extern_sky", "extern_cuew",
+			] + ( cyclesLibraries if includeCyclesLibrariesInPythonModule else [] ) + [
 				"OpenImageIO$OIIO_LIB_SUFFIX", "OpenImageIO_Util$OIIO_LIB_SUFFIX", "oslexec$OSL_LIB_SUFFIX", "openvdb$VDB_LIB_SUFFIX",
 				"oslquery$OSL_LIB_SUFFIX", "Alembic", "osdCPU", "OpenColorIO$OCIO_LIB_SUFFIX", "embree4", "Iex", "openpgl",
 			],

include/GafferImage/Sampler.h

@@ -81,7 +81,7 @@ class GAFFERIMAGE_API Sampler
 		/// @param channelName The channel to sample.
 		/// @param sampleWindow The area from which samples may be requested. It is an error to request samples outside this area.
 		/// @param boundingMode The method of handling samples that fall outside the data window.
-		Sampler( const GafferImage::ImagePlug *plug, const std::string &channelName, const Imath::Box2i &sampleWindow, BoundingMode boundingMode = Black );
+		Sampler( const GafferImage::ImagePlug *plug, const std::string &channelName, const Imath::Box2i &sampleWindow, BoundingMode boundingMode = Black, bool rememberContext = false );
 
 		/// Uses `parallelProcessTiles()` to fill the internal tile cache
 		/// with all tiles in the sample window. Allows `sample()` and
@@ -135,6 +135,7 @@ class GAFFERIMAGE_API Sampler
 		const std::string m_channelName;
 		Imath::Box2i m_sampleWindow;
 		Imath::Box2i m_dataWindow;
+		Gaffer::ContextPtr m_overrideContext;
 
 		std::vector< IECore::ConstFloatVectorDataPtr > m_dataCache;
 		std::vector< const float * > m_dataCacheRaw;

include/GafferImage/Sampler.inl

@@ -316,7 +316,15 @@ inline void Sampler::cachedData( Imath::V2i p, const float *& tileData, int &til
 		Imath::V2i tileOrigin( p.x & ~( ImagePlug::tileSize() - 1 ), p.y & ~( ImagePlug::tileSize() - 1 ) );
 
 		IECore::ConstFloatVectorDataPtr &cacheTilePtr = m_dataCache[ cacheIndex ];
-		cacheTilePtr = m_plug->channelData( m_channelName, tileOrigin );
+		if( m_overrideContext )
+		{
+			Gaffer::Context::Scope s( m_overrideContext.get() );
+			cacheTilePtr = m_plug->channelData( m_channelName, tileOrigin );
+		}
+		else
+		{
+			cacheTilePtr = m_plug->channelData( m_channelName, tileOrigin );
+		}
 		cacheTileRawPtr = &cacheTilePtr->readable()[0];
 	}
 

include/GafferOSL/OSLImage.h

@@ -84,6 +84,9 @@ class GAFFEROSL_API OSLImage : public GafferImage::ImageProcessor
 		GafferImage::Format computeFormat( const Gaffer::Context *context, const GafferImage::ImagePlug *parent ) const override;
 		Imath::Box2i computeDataWindow( const Gaffer::Context *context, const GafferImage::ImagePlug *parent ) const override;
 
+		Gaffer::ValuePlug::CachePolicy hashCachePolicy( const Gaffer::ValuePlug *output ) const override;
+
+
 	private :
 
 		GafferScene::ShaderPlug *shaderPlug();
@@ -105,6 +108,9 @@ class GAFFEROSL_API OSLImage : public GafferImage::ImageProcessor
 		Gaffer::StringVectorDataPlug *affectedChannelsPlug();
 		const Gaffer::StringVectorDataPlug *affectedChannelsPlug() const;
 
+		Gaffer::IntPlug *allImageDataNeededPlug();
+		const Gaffer::IntPlug *allImageDataNeededPlug() const;
+
 		void hashShading( const Gaffer::Context *context, IECore::MurmurHash &h ) const;
 		IECore::ConstCompoundDataPtr computeShading( const Gaffer::Context *context ) const;
 

include/GafferOSL/ShadingEngine.h

@@ -37,11 +37,16 @@
 #include "GafferOSL/Export.h"
 #include "GafferOSL/TypeIds.h"
 
+#include "GafferImage/ImagePlug.h"
+
 #include "IECoreScene/ShaderNetwork.h"
 
 #include "IECore/CompoundData.h"
 
+#include "OpenImageIO/ustring.h"
+
 #include "boost/container/flat_set.hpp"
+#include "boost/container/flat_map.hpp"
 
 namespace GafferOSL
 {
@@ -83,13 +88,17 @@ class GAFFEROSL_API ShadingEngine : public IECore::RefCounted
 		};
 
 		using Transforms = std::map<IECore::InternedString, Transform>;
+		using ImagePlugs = std::map<IECore::InternedString, const GafferImage::ImagePlug *>;
 
 		/// Append a unique hash representing this shading engine to `h`.
 		void hash( IECore::MurmurHash &h ) const;
-		IECore::CompoundDataPtr shade( const IECore::CompoundData *points, const Transforms &transforms = Transforms() ) const;
+		IECore::CompoundDataPtr shade( const IECore::CompoundData *points, const Transforms &transforms = Transforms(), const ImagePlugs &imagePlugs = ImagePlugs() ) const;
 
 		bool needsAttribute( const std::string &name ) const;
 		bool hasDeformation() const;
+		bool needsImageSamples() const;
+
+		IECore::MurmurHash hashPossibleImageSamples( const ImagePlugs &imagePlugs ) const;
 
 	private :
 
@@ -108,6 +117,10 @@ class GAFFEROSL_API ShadingEngine : public IECore::RefCounted
 
 		bool m_hasDeformation;
 
+		std::vector< OIIO::ustring > m_gafferTexturesRequested;
+
+		boost::container::flat_map< OIIO::ustring, int> m_gafferTextureIndices;
+
 		void *m_shaderGroupRef;
 
 };