void FromHoudiniGroupConverter::doUnnamedConversion( const GU_Detail *geo, Group *result, const CompoundObject *operands, const std::string &name ) const
{
	GU_Detail newGeo( (GU_Detail*)geo );
	GA_PrimitiveGroup *newGroup = static_cast<GA_PrimitiveGroup*>( newGeo.createInternalElementGroup( GA_ATTRIB_PRIMITIVE, "FromHoudiniGroupConverter__doUnnamedConversion" ) );
	newGroup->toggleRange( newGeo.getPrimitiveRange() );
	
	VisibleRenderablePtr renderable = 0;
	doGroupConversion( &newGeo, newGroup, renderable, operands );
	if ( renderable )
	{
		if ( Group *group = IECore::runTimeCast<Group>( renderable ) )
		{
			const Group::ChildContainer &children = group->children();
			for ( Group::ChildContainer::const_iterator it = children.begin(); it != children.end(); ++it )
			{
				if ( name != "" )
				{
					(*it)->blindData()->member<StringData>( "name", false, true )->writable() = name;
				}
				
				result->addChild( *it );
			}
		}
		else
		{
			if ( name != "" )
			{
				renderable->blindData()->member<StringData>( "name", false, true )->writable() = name;
			}
			
			result->addChild( renderable );
		}
	}
}
ObjectPtr FromHoudiniGroupConverter::doConversion( ConstCompoundObjectPtr operands ) const
{
	GU_DetailHandleAutoReadLock readHandle( handle() );
	const GU_Detail *geo = readHandle.getGdp();
	if ( !geo )
	{
		return 0;
	}
	
	size_t numResultPrims = 0;
	size_t numOrigPrims = geo->getNumPrimitives();
	
	GroupPtr result = new Group();
	
	if ( operands->member<const IntData>( "groupingMode" )->readable() == NameAttribute )
	{
		GA_ROAttributeRef attributeRef = geo->findPrimitiveAttribute( "name" );
		if ( attributeRef.isInvalid() || !attributeRef.isString() )
		{
			GU_Detail ungroupedGeo( (GU_Detail*)geo );
			GA_PrimitiveGroup *ungrouped = static_cast<GA_PrimitiveGroup*>( ungroupedGeo.createInternalElementGroup( GA_ATTRIB_PRIMITIVE, "FromHoudiniGroupConverter__ungroupedPrimitives" ) );
			ungrouped->toggleRange( ungroupedGeo.getPrimitiveRange() );
			
			VisibleRenderablePtr renderable = 0;
			doGroupConversion( &ungroupedGeo, ungrouped, renderable, operands );
			if ( renderable )
			{
				Group *group = runTimeCast<Group>( renderable );
				if ( group )
				{
					const Group::ChildContainer &children = group->children();
					for ( Group::ChildContainer::const_iterator it = children.begin(); it != children.end(); ++it )
					{
						result->addChild( *it );
					}
				}
				else
				{
					result->addChild( renderable );
				}
			}
			
			return result;
		}
		
		GU_Detail groupGeo( (GU_Detail*)geo );
		
		AttributePrimIdGroupMap groupMap;
		regroup( &groupGeo, groupMap, attributeRef );
		
		for ( AttributePrimIdGroupMapIterator it=groupMap.begin(); it != groupMap.end(); ++it )
		{
			convertAndAddPrimitive( &groupGeo, it->second, result, operands, it->first.first );
		}
	}
	else
	{
		for ( GA_GroupTable::iterator<GA_ElementGroup> it=geo->primitiveGroups().beginTraverse(); !it.atEnd(); ++it )
		{
			GA_PrimitiveGroup *group = static_cast<GA_PrimitiveGroup*>( it.group() );
			if ( group->getInternal() || group->isEmpty() )
			{
				continue;
			}

			VisibleRenderablePtr renderable = 0;
			numResultPrims += doGroupConversion( geo, group, renderable, operands );
			if( !renderable )
			{
				continue;
			}
			
			renderable->blindData()->member<StringData>( "name", false, true )->writable() = group->getName().toStdString();
			result->addChild( renderable );
		}

		if ( numOrigPrims == numResultPrims )
		{
			return result;
		}

		GU_Detail ungroupedGeo( (GU_Detail*)geo );
		GA_PrimitiveGroup *ungrouped = static_cast<GA_PrimitiveGroup*>( ungroupedGeo.createInternalElementGroup( GA_ATTRIB_PRIMITIVE, "FromHoudiniGroupConverter__ungroupedPrimitives" ) );
		for ( GA_GroupTable::iterator<GA_ElementGroup> it=geo->primitiveGroups().beginTraverse(); !it.atEnd(); ++it )
		{
			*ungrouped |= *static_cast<GA_PrimitiveGroup*>( it.group() );
		}
		ungrouped->toggleRange( ungroupedGeo.getPrimitiveRange() );

		if ( ungrouped->isEmpty() )
		{
			return result;
		}

		VisibleRenderablePtr renderable = 0;
		doGroupConversion( &ungroupedGeo, ungrouped, renderable, operands );
		if ( renderable )
		{
			result->addChild( renderable );
		}
	}
	
	return result;
}
ObjectPtr FromHoudiniGroupConverter::doConversion( ConstCompoundObjectPtr operands ) const
{
	GroupPtr result = new Group();
	
	if ( operands->member<const IntData>( "groupingMode" )->readable() == NameAttribute )
	{
		DetailSplitterPtr splitter = new DetailSplitter( handle() );
		std::vector<std::string> children;
		splitter->values( children );
		
		if ( children.empty() )
		{
			doUnnamedConversion( GU_DetailHandleAutoReadLock( handle() ).getGdp(), result, operands );
			return result;
		}
		
		for ( std::vector<std::string>::iterator it = children.begin(); it != children.end(); ++it )
		{
			const std::string &name = *it;
			GU_DetailHandle childHandle = splitter->split( name );
			if ( childHandle.isNull() )
			{
				continue;
			}
			
			GU_DetailHandleAutoReadLock readHandle( childHandle );
			const GU_Detail *childGeo = readHandle.getGdp();
			ObjectPtr child = doDetailConversion( childGeo, operands );
			if ( !child )
			{
				// this happens when mismatched primitives share the same name
				doUnnamedConversion( childGeo, result, operands, name );
			}
			else if ( VisibleRenderablePtr renderable = IECore::runTimeCast<VisibleRenderable>( child ) )
			{
				if ( name != "" )
				{
					renderable->blindData()->member<StringData>( "name", false, true )->writable() = name;
				}
				
				result->addChild( renderable );
			}
		}
	}
	else
	{
		GU_DetailHandleAutoReadLock readHandle( handle() );
		const GU_Detail *geo = readHandle.getGdp();
		if ( !geo )
		{
			return 0;
		}

		size_t numResultPrims = 0;
		size_t numOrigPrims = geo->getNumPrimitives();

		for ( GA_GroupTable::iterator<GA_ElementGroup> it=geo->primitiveGroups().beginTraverse(); !it.atEnd(); ++it )
		{
			GA_PrimitiveGroup *group = static_cast<GA_PrimitiveGroup*>( it.group() );
			if ( group->getInternal() || group->isEmpty() )
			{
				continue;
			}

			VisibleRenderablePtr renderable = 0;
			numResultPrims += doGroupConversion( geo, group, renderable, operands );
			if( !renderable )
			{
				continue;
			}
			
			renderable->blindData()->member<StringData>( "name", false, true )->writable() = group->getName().toStdString();
			result->addChild( renderable );
		}

		if ( numOrigPrims == numResultPrims )
		{
			return result;
		}

		GU_Detail ungroupedGeo( (GU_Detail*)geo );
		GA_PrimitiveGroup *ungrouped = static_cast<GA_PrimitiveGroup*>( ungroupedGeo.createInternalElementGroup( GA_ATTRIB_PRIMITIVE, "FromHoudiniGroupConverter__ungroupedPrimitives" ) );
		for ( GA_GroupTable::iterator<GA_ElementGroup> it=geo->primitiveGroups().beginTraverse(); !it.atEnd(); ++it )
		{
			*ungrouped |= *static_cast<GA_PrimitiveGroup*>( it.group() );
		}
		ungrouped->toggleRange( ungroupedGeo.getPrimitiveRange() );

		if ( ungrouped->isEmpty() )
		{
			return result;
		}

		VisibleRenderablePtr renderable = 0;
		doGroupConversion( &ungroupedGeo, ungrouped, renderable, operands );
		if ( renderable )
		{
			result->addChild( renderable );
		}
	}
	
	return result;
}
void IECoreMantra::ProceduralPrimitive::addVisibleRenderable( VisibleRenderablePtr renderable )
{
	ToHoudiniGeometryConverterPtr converter = ToHoudiniGeometryConverter::create( renderable.get() );
	if( !converter ) 
	{
		msg( Msg::Warning, "ProceduralPrimitive::addVisibleRenderable", "converter could not be found" );
		return;
	}
	GU_Detail *gdp = allocateGeometry();
	GU_DetailHandle handle;
	handle.allocateAndSet( (GU_Detail*)gdp, false );
	bool converted = converter->convert( handle );
	if ( !converted )
	{
		msg( Msg::Warning, "ProceduralPrimitive::addVisibleRenderable", "converter failed" );
		return;
	}
	/// \todo ToHoudiniGeometryConverter does not create a Houdini style uv attribute.
	/// We make one from s and t. This code should probably live in a converter or in an Op that
	/// remaps IECore conventions to common Houdini ones.
	MeshPrimitivePtr mesh = runTimeCast<MeshPrimitive> (renderable);
	if ( mesh )
	{
		gdp->addTextureAttribute( GA_ATTRIB_VERTEX );
		GEO_AttributeHandle auv = gdp->getAttribute( GA_ATTRIB_VERTEX, "uv" );
		GEO_AttributeHandle as = gdp->getAttribute( GA_ATTRIB_VERTEX, "s" );
		GEO_AttributeHandle at = gdp->getAttribute( GA_ATTRIB_VERTEX, "t" );
		if ( auv.isAttributeValid() && as.isAttributeValid() && at.isAttributeValid() )
		{
			GA_GBPrimitiveIterator it( *gdp );
			GA_Primitive *p = it.getPrimitive();
			while ( p )
			{
				for (int i = 0; i < p->getVertexCount(); ++i)
				{
					GA_Offset v = p->getVertexOffset(i);
					as.setVertex(v);
					at.setVertex(v);
					auv.setVertex(v);
					auv.setF( as.getF(0), 0 );
					auv.setF( ((at.getF(0) * -1.0f) + 1.0f), 1 ); // wat, t arrives upside down for some reason.
					auv.setF( 0.0f, 2 );
				}
				++it;
				p = it.getPrimitive();
			}
		}
	}

	if ( m_renderer->m_motionType == RendererImplementation::Geometry )
	{
		msg(Msg::Debug, "IECoreMantra::ProceduralPrimitive::addVisibleRenderable", "MotionBlur:Geometry" );
		if ( !m_renderer->m_motionTimes.empty() )
		{
			if ( (size_t)m_renderer->m_motionSize == m_renderer->m_motionTimes.size() )
			{
				openGeometryObject();
			}
			addGeometry(gdp, m_renderer->m_motionTimes.front());
			m_renderer->m_motionTimes.pop_front();
			if ( m_renderer->m_motionTimes.empty() )
			{
				applySettings();
				closeObject();
			}
		}
	}
	else if ( m_renderer->m_motionType == RendererImplementation::ConcatTransform ||
			  m_renderer->m_motionType == RendererImplementation::SetTransform )
	{
		// It isn't clear that this will give correct results. 
		// ConcatTransform may need to interpolate transform snapshots.
		msg(Msg::Debug, "IECoreMantra::ProceduralPrimitive::addVisibleRenderable", "MotionBlur:Transform" );
		openGeometryObject();
			addGeometry(gdp, 0.0f);
			while ( !m_renderer->m_motionTimes.empty() )
			{
				setPreTransform( convert< UT_Matrix4T<float> >(m_renderer->m_motionTransforms.front()),
								 m_renderer->m_motionTimes.front() );
				m_renderer->m_motionTimes.pop_front();
				m_renderer->m_motionTransforms.pop_front();
			}
			applySettings();
		closeObject();
		m_renderer->m_motionType = RendererImplementation::Unknown;
	}
	else if ( m_renderer->m_motionType == RendererImplementation::Velocity )
	{
		msg(Msg::Debug, "IECoreMantra::ProceduralPrimitive::addVisibleRenderable", "MotionBlur:Velocity" );
		import("global:fps", &m_fps, 1);
		import("camera:shutter", m_cameraShutter, 2);
		m_preBlur = -m_cameraShutter[0] / m_fps;
		m_postBlur = -m_cameraShutter[1] / m_fps;
		openGeometryObject();
			addGeometry(gdp, 0.0f);
			addVelocityBlurGeometry(gdp, m_preBlur, m_postBlur);
			applySettings();
		closeObject();
		m_renderer->m_motionType = RendererImplementation::Unknown;
	}
	else
	{
		msg(Msg::Debug, "IECoreMantra::ProceduralPrimitive::addVisibleRenderable", "MotionBlur:None" );
		openGeometryObject();
			addGeometry( gdp, 0.0f );
			setPreTransform( convert< UT_Matrix4T<float> >(m_renderer->m_transformStack.top()), 0.0f);
			applySettings();
		closeObject();
	}
}