Performs fast BVH construction using LBVH building approach. Algorithm uses spatial Morton codes to reduce the BVH construction problem to a sorting problem (radix sort – O(N) complexity). This Linear Bounding Volume Hierarchy (LBVH) builder produces BVH trees of lower quality compared to SAH-based BVH builders but it is over an order of magnitude faster (up to 3M triangles per second). More...

#include <BVH_LinearBuilder.hxx>

Inheritance diagram for BVH_LinearBuilder< T, N >:

[legend]

Public Types
typedef BVH::VectorType< T, N >::Type	BVH_VecNt

Public Types inherited from Standard_Transient
typedef void	base_type
	Returns a type descriptor about this object. More...

Public Member Functions
	BVH_LinearBuilder (const Standard_Integer theLeafNodeSize=BVH_Constants_LeafNodeSizeDefault, const Standard_Integer theMaxTreeDepth=BVH_Constants_MaxTreeDepth)
	Creates binned LBVH builder. More...

virtual	~BVH_LinearBuilder ()
	Releases resources of LBVH builder. More...

virtual void	Build (BVH_Set< T, N > theSet, BVH_Tree< T, N > theBVH, const BVH_Box< T, N > &theBox) const override
	Builds BVH. More...

Public Member Functions inherited from BVH_BuilderTransient
Standard_Integer	MaxTreeDepth () const
	Returns the maximum depth of constructed BVH. More...

Standard_Integer	LeafNodeSize () const
	Returns the maximum number of sub-elements in the leaf. More...

Public Member Functions inherited from Standard_Transient
	Standard_Transient ()
	Empty constructor. More...

	Standard_Transient (const Standard_Transient &)
	Copy constructor – does nothing. More...

Standard_Transient &	operator= (const Standard_Transient &)
	Assignment operator, needed to avoid copying reference counter. More...

virtual	~Standard_Transient ()
	Destructor must be virtual. More...

virtual void	Delete () const
	Memory deallocator for transient classes. More...

virtual const opencascade::handle< Standard_Type > &	DynamicType () const
	Returns a type descriptor about this object. More...

Standard_Boolean	IsInstance (const opencascade::handle< Standard_Type > &theType) const
	Returns a true value if this is an instance of Type. More...

Standard_Boolean	IsInstance (const Standard_CString theTypeName) const
	Returns a true value if this is an instance of TypeName. More...

Standard_Boolean	IsKind (const opencascade::handle< Standard_Type > &theType) const
	Returns true if this is an instance of Type or an instance of any class that inherits from Type. Note that multiple inheritance is not supported by OCCT RTTI mechanism. More...

Standard_Boolean	IsKind (const Standard_CString theTypeName) const
	Returns true if this is an instance of TypeName or an instance of any class that inherits from TypeName. Note that multiple inheritance is not supported by OCCT RTTI mechanism. More...

Standard_Transient *	This () const
	Returns non-const pointer to this object (like const_cast). For protection against creating handle to objects allocated in stack or call from constructor, it will raise exception Standard_ProgramError if reference counter is zero. More...

Standard_Integer	GetRefCount () const
	Get the reference counter of this object. More...

void	IncrementRefCounter () const
	Increments the reference counter of this object. More...

Standard_Integer	DecrementRefCounter () const
	Decrements the reference counter of this object; returns the decremented value. More...

Protected Types
typedef NCollection_Array1< BVH_EncodedLink >::iterator	LinkIterator

Protected Member Functions
Standard_Integer	emitHierachy (BVH_Tree< T, N > *theBVH, const NCollection_Array1< BVH_EncodedLink > &theEncodedLinks, const Standard_Integer theBit, const Standard_Integer theShift, const Standard_Integer theStart, const Standard_Integer theFinal) const
	Emits hierarchy from sorted Morton codes. More...

Standard_Integer	lowerBound (const NCollection_Array1< BVH_EncodedLink > &theEncodedLinks, Standard_Integer theStart, Standard_Integer theFinal, Standard_Integer theDigit) const
	Returns index of the first element which does not compare less than the given one. More...

Protected Member Functions inherited from BVH_Builder< T, N >
	BVH_Builder (const Standard_Integer theLeafNodeSize, const Standard_Integer theMaxTreeDepth)
	Creates new abstract BVH builder. More...

void	updateDepth (BVH_Tree< T, N > *theBVH, const Standard_Integer theLevel) const
	Updates depth of constructed BVH tree. More...

Protected Member Functions inherited from BVH_BuilderTransient
	BVH_BuilderTransient (const Standard_Integer theLeafNodeSize, const Standard_Integer theMaxTreeDepth)
	Creates new abstract BVH builder. More...

Additional Inherited Members
Static Public Member Functions inherited from Standard_Transient
static const char *	get_type_name ()
	Returns a type descriptor about this object. More...

static const opencascade::handle< Standard_Type > &	get_type_descriptor ()
	Returns type descriptor of Standard_Transient class. More...

Protected Attributes inherited from BVH_BuilderTransient
Standard_Integer	myMaxTreeDepth
	Maximum depth of constructed BVH. More...

Standard_Integer	myLeafNodeSize
	Maximum number of objects per leaf. More...

Detailed Description

template<class T, int N>
class BVH_LinearBuilder< T, N >

Performs fast BVH construction using LBVH building approach. Algorithm uses spatial Morton codes to reduce the BVH construction problem to a sorting problem (radix sort – O(N) complexity). This Linear Bounding Volume Hierarchy (LBVH) builder produces BVH trees of lower quality compared to SAH-based BVH builders but it is over an order of magnitude faster (up to 3M triangles per second).

For more details see: C. Lauterbach, M. Garland, S. Sengupta, D. Luebke, and D. Manocha. Fast BVH construction on GPUs. Eurographics, 2009.

Member Typedef Documentation

◆ BVH_VecNt

template<class T , int N>

typedef BVH::VectorType<T, N>::Type BVH_LinearBuilder< T, N >::BVH_VecNt

◆ LinkIterator

template<class T , int N>

typedef NCollection_Array1<BVH_EncodedLink>::iterator BVH_LinearBuilder< T, N >::LinkIterator

protected

Constructor & Destructor Documentation