Cycles : Refactored the VDB Volume code, it now defers voxel creation…

… into the scene lock.

Changes.md

@@ -68,6 +68,7 @@ Fixes
 - Window : Fixed handling of `**kw` constructor arguments. These were being passed to the `QWidget` constructor where they caused errors, instead of being passed to the ContainerWidget base class.
 - PresetsPlugValueWidget : Fixed label update for context-sensitive presets.
 - PlugValueWidget : Fixed value update when auxiliary plugs depend on the context but the primary plugs do not.
+- Cycles : OpenVDBs will now render and allow shader updates in a live render.
 
 API
 ---

SConstruct

@@ -1300,6 +1300,10 @@ libraries = {
 				( "CCL_NAMESPACE_END", "}" ),
 				( "WITH_OSL", "1" ),
 				( "WITH_CYCLES_PATH_GUIDING", "1" ),
+				( "WITH_OCIO", "1"),
+				( "WITH_OPENSUBDIV", "1"),
+				( "WITH_OPENVDB", "1"),
+				( "WITH_NANOVDB", "1")
 			],
 			"FRAMEWORKS" : [ "Foundation", "Metal", "IOKit" ],
 		},
@@ -1316,7 +1320,12 @@ libraries = {
 			"CPPDEFINES" : [
 				( "CCL_NAMESPACE_BEGIN", "namespace ccl {" ),
 				( "CCL_NAMESPACE_END", "}" ),
+				( "WITH_OSL", "1" ),
 				( "WITH_CYCLES_PATH_GUIDING", "1" ),
+				( "WITH_OCIO", "1"),
+				( "WITH_OPENSUBDIV", "1"),
+				( "WITH_OPENVDB", "1"),
+				( "WITH_NANOVDB", "1")
 			],
 		},
 		"requiredOptions" : [ "CYCLES_ROOT" ],

include/GafferCycles/IECoreCyclesPreview/CameraAlgo.h

@@ -52,7 +52,7 @@ namespace CameraAlgo
 {
 
 /// Converts the specified IECoreScene::Camera into a ccl::Camera.
-IECORECYCLES_API ccl::Camera *convert( const IECoreScene::Camera *camera, const std::string &nodeName, ccl::Scene *scene = nullptr );
+IECORECYCLES_API ccl::Camera *convert( const IECoreScene::Camera *camera, const std::string &nodeName );
 
 } // namespace CameraAlgo
 

include/GafferCycles/IECoreCyclesPreview/GeometryAlgo.h

@@ -40,11 +40,14 @@
 
 #include "IECore/Object.h"
 
+#include "IECoreVDB/VDBObject.h"
+
 #include <vector>
 
 // Cycles
 IECORE_PUSH_DEFAULT_VISIBILITY
 #include "scene/geometry.h"
+#include "scene/volume.h"
 // Currently only VDBs need scene to get to the image manager
 #include "scene/scene.h"
 IECORE_POP_DEFAULT_VISIBILITY
@@ -56,22 +59,25 @@ namespace GeometryAlgo
 {
 
 /// Converts the specified `IECore::Object` into `ccl::Geometry`.
-IECORECYCLES_API ccl::Geometry *convert( const IECore::Object *object, const std::string &nodeName, ccl::Scene *scene = nullptr );
+IECORECYCLES_API ccl::Geometry *convert( const IECore::Object *object, const std::string &nodeName );
 /// As above, but converting a moving object. If no motion converter
 /// is available, the first sample is converted instead.
-IECORECYCLES_API ccl::Geometry *convert( const std::vector<const IECore::Object *> &samples, const std::vector<float> &times, const int frame, const std::string &nodeName, ccl::Scene *scene = nullptr );
+IECORECYCLES_API ccl::Geometry *convert( const std::vector<const IECore::Object *> &samples, const std::vector<float> &times, const int frame, const std::string &nodeName );
 
 /// Converts a primitive variable to a `ccl::Attribute` inside of a `ccl::AttributeSet`.
 IECORECYCLES_API void convertPrimitiveVariable( const std::string &name, const IECoreScene::PrimitiveVariable &primitiveVariable, ccl::AttributeSet &attributes, ccl::AttributeElement attributeElement );
 
+/// Converts voxel grids from a VDB object.
+IECORECYCLES_API void convertVoxelGrids( const IECoreVDB::VDBObject *vdbObject, ccl::Volume *geometry, ccl::Scene *scene, const float frame = 0.0f, const int precision_ = 0 );
+
 /// Signature of a function which can convert to `ccl:Geometry`.
 /// \todo There's really no need to pass the node name here, because it's not a unique handle that
 /// needs to be provided when creating the Geometry (like it is in Arnold). The caller can just set the name
 /// afterwards if they want to.
-using Converter = ccl::Geometry *(*)( const IECore::Object *, const std::string &, ccl::Scene * );
+using Converter = ccl::Geometry *(*)( const IECore::Object *, const std::string & );
 /// Signature of a function which can convert a series of IECore::Object
 /// samples into a moving `ccl:Geometry` object.
-using MotionConverter = ccl::Geometry *(*)( const std::vector<const IECore::Object *> &, const std::vector<float> &, const int, const std::string &, ccl::Scene * );
+using MotionConverter = ccl::Geometry *(*)( const std::vector<const IECore::Object *> &, const std::vector<float> &, const int, const std::string & );
 
 /// Registers a converter for a specific type.
 /// Use the ConverterDescription utility class in preference to
@@ -87,8 +93,8 @@ class ConverterDescription
 	public :
 
 		/// Type-specific conversion functions.
-		using Converter = ccl::Geometry *(*)( const T *, const std::string &, ccl::Scene * );
-		using MotionConverter = ccl::Geometry *(*)( const std::vector<const T *> &, const std::vector<float> &, const int, const std::string &, ccl::Scene * );
+		using Converter = ccl::Geometry *(*)( const T *, const std::string & );
+		using MotionConverter = ccl::Geometry *(*)( const std::vector<const T *> &, const std::vector<float> &, const int, const std::string & );
 
 		ConverterDescription( Converter converter, MotionConverter motionConverter = nullptr )
 		{

python/GafferCyclesTest/IECoreCyclesPreviewTest/RendererTest.py

@@ -34,6 +34,7 @@
 #
 ##########################################################################
 
+import pathlib
 import math
 import time
 import unittest
@@ -43,6 +44,7 @@
 import IECore
 import IECoreScene
 import IECoreImage
+import IECoreVDB
 
 import GafferScene
 import GafferCycles
@@ -1823,5 +1825,78 @@ def testUnsupportedShaderParameters( self ) :
 			"Unsupported socket type `transform` for socket `ob_tfm` on node .*"
 		)
 
+	def testVDB( self ) :
+
+		renderer = GafferScene.Private.IECoreScenePreview.Renderer.create(
+			"Cycles",
+			GafferScene.Private.IECoreScenePreview.Renderer.RenderType.Interactive,
+		)
+
+		camera = renderer.camera(
+			"testCamera",
+			IECoreScene.Camera(
+				parameters = {
+					"resolution" : imath.V2i( 64, 64 ),
+				}
+			),
+			renderer.attributes( IECore.CompoundObject() )
+		)
+		camera.transform( imath.M44f().translate( imath.V3f( 0, 45, 150 ) ) )
+
+		renderer.option( "camera", IECore.StringData( "testCamera" ) )
+
+		renderer.output(
+			"testOutput",
+			IECoreScene.Output(
+				"test",
+				"ieDisplay",
+				"rgba",
+				{
+					"driverType" : "ImageDisplayDriver",
+					"handle" : "testVDB",
+				}
+			)
+		)
+
+		renderer.object(
+			"/vdb",
+			IECoreVDB.VDBObject( pathlib.Path( __file__ ).parent / ".." / ".." / "GafferVDBTest" / "data" / "smoke.vdb" ), # todo - can't figure out how to load in a vdb...
+			renderer.attributes( IECore.CompoundObject ( {
+				"cycles:volume" : IECoreScene.ShaderNetwork(
+					shaders = {
+						"output" : IECoreScene.Shader( "principled_volume", "cycles:volume", { "density_attribute" : "density" } )
+					},
+					output = "output",
+				)
+			} ) )
+		)
+
+		renderer.light(
+			"/light",
+			None,
+			renderer.attributes( IECore.CompoundObject ( {
+				"cycles:light" : IECoreScene.ShaderNetwork(
+					shaders = {
+						"output" : IECoreScene.Shader( "background_light", "cycles:light", { "color" : imath.Color3f( 1, 1, 1 ) } ),
+					},
+					output = "output",
+				),
+			} ) )
+		)
+
+		renderer.render()
+		time.sleep( 2 )
+
+		image = IECoreImage.ImageDisplayDriver.storedImage( "testVDB" )
+		self.assertIsInstance( image, IECoreImage.ImagePrimitive )
+
+		testPixel = self.__colorAtUV( image, imath.V2f( 0.5 ) )
+		self.assertGreater( testPixel.r, 0 )
+		self.assertGreater( testPixel.g, 0 )
+		self.assertGreater( testPixel.b, 0 )
+
+		del camera
+		del v
+
 if __name__ == "__main__":
 	unittest.main()

python/GafferCyclesUI/CyclesAttributesUI.py

@@ -69,7 +69,7 @@ def __subdivisionSummary( plug ) :
 def __volumeSummary( plug ) :
 
 	info = []
-	for childName in ( "volumeClipping", "volumeStepSize", "volumeObjectSpace" ) :
+	for childName in ( "volumeClipping", "volumeStepSize", "volumeObjectSpace", "volumeVelocityScale", "volumePrecision" ) :
 		if plug[childName]["enabled"].getValue() :
 			info.append( IECore.CamelCase.toSpaced( childName ) + ( " On" if plug[childName]["value"].getValue() else " Off" ) )
 
@@ -341,6 +341,40 @@ def __shaderSummary( plug ) :
 
 		],
 
+		"attributes.volumeVelocityScale" : [
+
+			"description",
+			"""
+			Volume velocity scale to multiply with an existing velocity.
+			""",
+
+			"layout:section", "Volume",
+
+		],
+
+		"attributes.volumePrecision" : [
+
+			"description",
+			"""
+			Specifies volume data precision, lower values reduce
+			memory consumption at the cost of detail.
+			""",
+
+			"layout:section", "Volume",
+
+		],
+
+		"attributes.volumePrecision.value" : [
+
+			"preset:Full", "full",
+			"preset:Half", "half",
+
+			"plugValueWidget:type", "GafferUI.PresetsPlugValueWidget",
+
+		],
+
+		# Object
+
 		"attributes.assetName" : [
 
 			"description",

src/GafferCycles/CyclesAttributes.cpp

@@ -72,7 +72,9 @@ CyclesAttributes::CyclesAttributes( const std::string &name )
 	// Volume
 	attributes->addChild( new Gaffer::NameValuePlug( "cycles:volume_clipping", new IECore::FloatData( 0.001f ), false, "volumeClipping" ) );
 	attributes->addChild( new Gaffer::NameValuePlug( "cycles:volume_step_size", new IECore::FloatData( 0.0f ), false, "volumeStepSize" ) );
-	attributes->addChild( new Gaffer::NameValuePlug( "cycles:volume_object_space", new IECore::BoolData( true ), false, "volumeObjectSpace" ) );
+	attributes->addChild( new Gaffer::NameValuePlug( "cycles:volume_object_space", new IECore::BoolData( false ), false, "volumeObjectSpace" ) );
+	attributes->addChild( new Gaffer::NameValuePlug( "cycles:volume_velocity_scale", new IECore::FloatData( 1.0f ), false, "volumeVelocityScale" ) );
+	attributes->addChild( new Gaffer::NameValuePlug( "cycles:volume_precision", new IECore::StringData( "full" ), false, "volumePrecision" ) );
 
 	// Per-object parameters
 	attributes->addChild( new Gaffer::NameValuePlug( "cycles:dupli_generated", new IECore::V3fData( Imath::V3f( 0.0f ) ), false, "dupliGenerated" ) );

src/GafferCycles/IECoreCyclesPreview/CameraAlgo.cpp

@@ -177,7 +177,7 @@ namespace CameraAlgo
 
 {
 
-ccl::Camera *convert( const IECoreScene::Camera *camera, const std::string &nodeName, ccl::Scene *scene )
+ccl::Camera *convert( const IECoreScene::Camera *camera, const std::string &nodeName )
 {
 	return convertCommon( camera, nodeName );
 }

src/GafferCycles/IECoreCyclesPreview/CurvesAlgo.cpp

@@ -133,14 +133,14 @@ ccl::Hair *convertCommon( const IECoreScene::CurvesPrimitive *curve )
 	return hair;
 }
 
-ccl::Geometry *convert( const IECoreScene::CurvesPrimitive *curve, const std::string &nodeName, ccl::Scene *scene )
+ccl::Geometry *convert( const IECoreScene::CurvesPrimitive *curve, const std::string &nodeName )
 {
 	ccl::Hair *hair = convertCommon( curve );
 	hair->name = ccl::ustring( nodeName.c_str() );
 	return hair;
 }
 
-ccl::Geometry *convert( const vector<const IECoreScene::CurvesPrimitive *> &curves, const std::vector<float> &times, const int frameIdx, const std::string &nodeName, ccl::Scene *scene )
+ccl::Geometry *convert( const vector<const IECoreScene::CurvesPrimitive *> &curves, const std::vector<float> &times, const int frameIdx, const std::string &nodeName )
 {
 	const int numSamples = curves.size();