VTK

Generate axis aligned BBox tree for raycasting and other Locator based searches. More...
#include <vtkModifiedBSPTree.h>
Public Types  
typedef vtkAbstractCellLocator  Superclass 
Standard TypeMacro. More...  
Public Types inherited from vtkAbstractCellLocator  
typedef vtkLocator  Superclass 
Public Types inherited from vtkLocator  
typedef vtkObject  Superclass 
Standard type and print methods. More...  
Public Member Functions  
virtual vtkTypeBool  IsA (const char *type) 
Return 1 if this class is the same type of (or a subclass of) the named class. More...  
vtkModifiedBSPTree *  NewInstance () const 
void  PrintSelf (ostream &os, vtkIndent indent) override 
Methods invoked by print to print information about the object including superclasses. More...  
void  FreeSearchStructure () override 
Free tree memory. More...  
void  BuildLocator () override 
Build Tree. More...  
void  GenerateRepresentation (int level, vtkPolyData *pd) override 
Generate BBox representation of Nth level. More...  
virtual void  GenerateRepresentationLeafs (vtkPolyData *pd) 
Generate BBox representation of all leaf nodes. More...  
int  IntersectWithLine (const double p1[3], const double p2[3], double tol, double &t, double x[3], double pcoords[3], int &subId, vtkIdType &cellId) override 
Return intersection point (if any) AND the cell which was intersected by the finite line. More...  
int  IntersectWithLine (const double p1[3], const double p2[3], double tol, double &t, double x[3], double pcoords[3], int &subId, vtkIdType &cellId, vtkGenericCell *cell) override 
Return intersection point (if any) AND the cell which was intersected by the finite line. More...  
virtual int  IntersectWithLine (const double p1[3], const double p2[3], const double tol, vtkPoints *points, vtkIdList *cellIds) 
Take the passed line segment and intersect it with the data set. More...  
vtkIdType  FindCell (double x[3], double tol2, vtkGenericCell *GenCell, double pcoords[3], double *weights) override 
Test a point to find if it is inside a cell. More...  
bool  InsideCellBounds (double x[3], vtkIdType cell_ID) override 
Quickly test if a point is inside the bounds of a particular cell. More...  
vtkIdListCollection *  GetLeafNodeCellInformation () 
After subdivision has completed, one may wish to query the tree to find which cells are in which leaf nodes. More...  
virtual int  IntersectWithLine (const double p1[3], const double p2[3], double tol, double &t, double x[3], double pcoords[3], int &subId) 
Return intersection point (if any) of finite line with cells contained in cell locator. More...  
virtual int  IntersectWithLine (const double p1[3], const double p2[3], double tol, double &t, double x[3], double pcoords[3], int &subId, vtkIdType &cellId) 
Return intersection point (if any) AND the cell which was intersected by the finite line. More...  
virtual int  IntersectWithLine (const double p1[3], const double p2[3], double tol, double &t, double x[3], double pcoords[3], int &subId, vtkIdType &cellId, vtkGenericCell *cell) 
Return intersection point (if any) AND the cell which was intersected by the finite line. More...  
virtual int  IntersectWithLine (const double p1[3], const double p2[3], vtkPoints *points, vtkIdList *cellIds) 
Take the passed line segment and intersect it with the data set. More...  
virtual vtkIdType  FindCell (double x[3]) 
Returns the Id of the cell containing the point, returns 1 if no cell found. More...  
virtual vtkIdType  FindCell (double x[3], double tol2, vtkGenericCell *GenCell, double pcoords[3], double *weights) 
Find the cell containing a given point. More...  
Public Member Functions inherited from vtkAbstractCellLocator  
vtkAbstractCellLocator *  NewInstance () const 
virtual void  SetNumberOfCellsPerNode (int) 
Specify the preferred/maximum number of cells in each node/bucket. More...  
virtual int  GetNumberOfCellsPerNode () 
virtual void  SetCacheCellBounds (vtkTypeBool) 
Boolean controls whether the bounds of each cell are computed only once and then saved. More...  
virtual vtkTypeBool  GetCacheCellBounds () 
virtual void  CacheCellBoundsOn () 
virtual void  CacheCellBoundsOff () 
virtual void  SetRetainCellLists (vtkTypeBool) 
Boolean controls whether to maintain list of cells in each node. More...  
virtual vtkTypeBool  GetRetainCellLists () 
virtual void  RetainCellListsOn () 
virtual void  RetainCellListsOff () 
virtual void  SetLazyEvaluation (vtkTypeBool) 
Most Locators build their search structures during BuildLocator but some may delay construction until it is actually needed. More...  
virtual vtkTypeBool  GetLazyEvaluation () 
virtual void  LazyEvaluationOn () 
virtual void  LazyEvaluationOff () 
virtual void  SetUseExistingSearchStructure (vtkTypeBool) 
Some locators support querying a new dataset without rebuilding the search structure (typically this may occur when a dataset changes due to a time update, but is actually the same topology) Turning on this flag enables some locators to skip the rebuilding phase. More...  
virtual vtkTypeBool  GetUseExistingSearchStructure () 
virtual void  UseExistingSearchStructureOn () 
virtual void  UseExistingSearchStructureOff () 
virtual int  IntersectWithLine (const double p1[3], const double p2[3], double tol, double &t, double x[3], double pcoords[3], int &subId) 
Return intersection point (if any) of finite line with cells contained in cell locator. More...  
virtual int  IntersectWithLine (const double p1[3], const double p2[3], vtkPoints *points, vtkIdList *cellIds) 
Take the passed line segment and intersect it with the data set. More...  
virtual void  FindClosestPoint (const double x[3], double closestPoint[3], vtkIdType &cellId, int &subId, double &dist2) 
Return the closest point and the cell which is closest to the point x. More...  
virtual void  FindClosestPoint (const double x[3], double closestPoint[3], vtkGenericCell *cell, vtkIdType &cellId, int &subId, double &dist2) 
Return the closest point and the cell which is closest to the point x. More...  
virtual vtkIdType  FindClosestPointWithinRadius (double x[3], double radius, double closestPoint[3], vtkIdType &cellId, int &subId, double &dist2) 
Return the closest point within a specified radius and the cell which is closest to the point x. More...  
virtual vtkIdType  FindClosestPointWithinRadius (double x[3], double radius, double closestPoint[3], vtkGenericCell *cell, vtkIdType &cellId, int &subId, double &dist2) 
Return the closest point within a specified radius and the cell which is closest to the point x. More...  
virtual vtkIdType  FindClosestPointWithinRadius (double x[3], double radius, double closestPoint[3], vtkGenericCell *cell, vtkIdType &cellId, int &subId, double &dist2, int &inside) 
Return the closest point within a specified radius and the cell which is closest to the point x. More...  
virtual void  FindCellsWithinBounds (double *bbox, vtkIdList *cells) 
Return a list of unique cell ids inside of a given bounding box. More...  
virtual void  FindCellsAlongLine (const double p1[3], const double p2[3], double tolerance, vtkIdList *cells) 
Given a finite line defined by the two points (p1,p2), return the list of unique cell ids in the buckets containing the line. More...  
virtual vtkIdType  FindCell (double x[3]) 
Returns the Id of the cell containing the point, returns 1 if no cell found. More...  
Public Member Functions inherited from vtkLocator  
vtkLocator *  NewInstance () const 
virtual void  SetDataSet (vtkDataSet *) 
Build the locator from the points/cells defining this dataset. More...  
virtual vtkDataSet *  GetDataSet () 
virtual void  SetMaxLevel (int) 
Set the maximum allowable level for the tree. More...  
virtual int  GetMaxLevel () 
virtual int  GetLevel () 
Get the level of the locator (determined automatically if Automatic is true). More...  
virtual void  SetAutomatic (vtkTypeBool) 
Boolean controls whether locator depth/resolution of locator is computed automatically from average number of entities in bucket. More...  
virtual vtkTypeBool  GetAutomatic () 
virtual void  AutomaticOn () 
virtual void  AutomaticOff () 
virtual void  SetTolerance (double) 
Specify absolute tolerance (in world coordinates) for performing geometric operations. More...  
virtual double  GetTolerance () 
virtual void  Update () 
Cause the locator to rebuild itself if it or its input dataset has changed. More...  
virtual void  Initialize () 
Initialize locator. More...  
virtual vtkMTimeType  GetBuildTime () 
Return the time of the last data structure build. More...  
void  Register (vtkObjectBase *o) override 
Handle the PointSet <> Locator loop. More...  
void  UnRegister (vtkObjectBase *o) override 
Decrease the reference count (release by another object). More...  
Public Member Functions inherited from vtkObject  
vtkBaseTypeMacro (vtkObject, vtkObjectBase)  
virtual void  DebugOn () 
Turn debugging output on. More...  
virtual void  DebugOff () 
Turn debugging output off. More...  
bool  GetDebug () 
Get the value of the debug flag. More...  
void  SetDebug (bool debugFlag) 
Set the value of the debug flag. More...  
virtual void  Modified () 
Update the modification time for this object. More...  
virtual vtkMTimeType  GetMTime () 
Return this object's modified time. More...  
unsigned long  AddObserver (unsigned long event, vtkCommand *, float priority=0.0f) 
Allow people to add/remove/invoke observers (callbacks) to any VTK object. More...  
unsigned long  AddObserver (const char *event, vtkCommand *, float priority=0.0f) 
vtkCommand *  GetCommand (unsigned long tag) 
void  RemoveObserver (vtkCommand *) 
void  RemoveObservers (unsigned long event, vtkCommand *) 
void  RemoveObservers (const char *event, vtkCommand *) 
vtkTypeBool  HasObserver (unsigned long event, vtkCommand *) 
vtkTypeBool  HasObserver (const char *event, vtkCommand *) 
void  RemoveObserver (unsigned long tag) 
void  RemoveObservers (unsigned long event) 
void  RemoveObservers (const char *event) 
void  RemoveAllObservers () 
vtkTypeBool  HasObserver (unsigned long event) 
vtkTypeBool  HasObserver (const char *event) 
template<class U , class T >  
unsigned long  AddObserver (unsigned long event, U observer, void(T::*callback)(), float priority=0.0f) 
Overloads to AddObserver that allow developers to add class member functions as callbacks for events. More...  
template<class U , class T >  
unsigned long  AddObserver (unsigned long event, U observer, void(T::*callback)(vtkObject *, unsigned long, void *), float priority=0.0f) 
template<class U , class T >  
unsigned long  AddObserver (unsigned long event, U observer, bool(T::*callback)(vtkObject *, unsigned long, void *), float priority=0.0f) 
Allow user to set the AbortFlagOn() with the return value of the callback method. More...  
int  InvokeEvent (unsigned long event, void *callData) 
This method invokes an event and return whether the event was aborted or not. More...  
int  InvokeEvent (const char *event, void *callData) 
int  InvokeEvent (unsigned long event) 
int  InvokeEvent (const char *event) 
Public Member Functions inherited from vtkObjectBase  
const char *  GetClassName () const 
Return the class name as a string. More...  
virtual void  Delete () 
Delete a VTK object. More...  
virtual void  FastDelete () 
Delete a reference to this object. More...  
void  InitializeObjectBase () 
void  Print (ostream &os) 
Print an object to an ostream. More...  
virtual void  PrintHeader (ostream &os, vtkIndent indent) 
virtual void  PrintTrailer (ostream &os, vtkIndent indent) 
int  GetReferenceCount () 
Return the current reference count of this object. More...  
void  SetReferenceCount (int) 
Sets the reference count. More...  
void  PrintRevisions (ostream &) 
Legacy. More...  
Static Public Member Functions  
static vtkTypeBool  IsTypeOf (const char *type) 
static vtkModifiedBSPTree *  SafeDownCast (vtkObjectBase *o) 
static vtkModifiedBSPTree *  New () 
Construct with maximum 32 cells per node. More...  
Static Public Member Functions inherited from vtkAbstractCellLocator  
static vtkTypeBool  IsTypeOf (const char *type) 
static vtkAbstractCellLocator *  SafeDownCast (vtkObjectBase *o) 
Static Public Member Functions inherited from vtkLocator  
static vtkTypeBool  IsTypeOf (const char *type) 
static vtkLocator *  SafeDownCast (vtkObjectBase *o) 
Static Public Member Functions inherited from vtkObject  
static vtkObject *  New () 
Create an object with Debug turned off, modified time initialized to zero, and reference counting on. More...  
static void  BreakOnError () 
This method is called when vtkErrorMacro executes. More...  
static void  SetGlobalWarningDisplay (int val) 
This is a global flag that controls whether any debug, warning or error messages are displayed. More...  
static void  GlobalWarningDisplayOn () 
static void  GlobalWarningDisplayOff () 
static int  GetGlobalWarningDisplay () 
Static Public Member Functions inherited from vtkObjectBase  
static vtkTypeBool  IsTypeOf (const char *name) 
Return 1 if this class type is the same type of (or a subclass of) the named class. More...  
static vtkObjectBase *  New () 
Create an object with Debug turned off, modified time initialized to zero, and reference counting on. More...  
Protected Member Functions  
virtual vtkObjectBase *  NewInstanceInternal () const 
vtkModifiedBSPTree ()  
~vtkModifiedBSPTree () override  
void  Subdivide (BSPNode *node, Sorted_cell_extents_Lists *lists, vtkDataSet *dataSet, vtkIdType nCells, int depth, int maxlevel, vtkIdType maxCells, int &MaxDepth) 
virtual int  IntersectCellInternal (vtkIdType cell_ID, const double p1[3], const double p2[3], const double tol, double &t, double ipt[3], double pcoords[3], int &subId) 
void  BuildLocatorIfNeeded () 
void  ForceBuildLocator () 
void  BuildLocatorInternal () 
Protected Member Functions inherited from vtkAbstractCellLocator  
vtkAbstractCellLocator ()  
~vtkAbstractCellLocator () override  
virtual bool  StoreCellBounds () 
This command is used internally by the locator to copy all cell Bounds into the internal CellBounds array. More...  
virtual void  FreeCellBounds () 
Protected Member Functions inherited from vtkLocator  
vtkLocator ()  
~vtkLocator () override  
void  ReportReferences (vtkGarbageCollector *) override 
Protected Member Functions inherited from vtkObject  
vtkObject ()  
~vtkObject () override  
void  RegisterInternal (vtkObjectBase *, vtkTypeBool check) override 
void  UnRegisterInternal (vtkObjectBase *, vtkTypeBool check) override 
void  InternalGrabFocus (vtkCommand *mouseEvents, vtkCommand *keypressEvents=nullptr) 
These methods allow a command to exclusively grab all events. More...  
void  InternalReleaseFocus () 
Protected Member Functions inherited from vtkObjectBase  
vtkObjectBase ()  
virtual  ~vtkObjectBase () 
virtual void  CollectRevisions (ostream &) 
vtkObjectBase (const vtkObjectBase &)  
void  operator= (const vtkObjectBase &) 
Protected Attributes  
BSPNode *  mRoot 
int  npn 
int  nln 
int  tot_depth 
Protected Attributes inherited from vtkAbstractCellLocator  
int  NumberOfCellsPerNode 
vtkTypeBool  RetainCellLists 
vtkTypeBool  CacheCellBounds 
vtkTypeBool  LazyEvaluation 
vtkTypeBool  UseExistingSearchStructure 
vtkGenericCell *  GenericCell 
double(*  CellBounds )[6] 
Protected Attributes inherited from vtkLocator  
vtkDataSet *  DataSet 
vtkTypeBool  Automatic 
double  Tolerance 
int  MaxLevel 
int  Level 
vtkTimeStamp  BuildTime 
Protected Attributes inherited from vtkObject  
bool  Debug 
vtkTimeStamp  MTime 
vtkSubjectHelper *  SubjectHelper 
Protected Attributes inherited from vtkObjectBase  
std::atomic< int32_t >  ReferenceCount 
vtkWeakPointerBase **  WeakPointers 
Generate axis aligned BBox tree for raycasting and other Locator based searches.
vtkModifiedBSPTree creates an evenly balanced BSP tree using a top down implementation. Axis aligned split planes are found which evenly divide cells into two buckets. Generally a split plane will intersect some cells and these are usually stored in both child nodes of the current parent. (Or split into separate cells which we cannot consider in this case). Storing cells in multiple buckets creates problems associated with multiple tests against rays and increases the required storage as complex meshes will have many cells straddling a split plane (and further splits may cause multiple copies of these).
During a discussion with Arno Formella in 1998 he suggested using a third child node to store objects which straddle split planes. I've not seen this published (Yes!  see below), but thought it worth trying. This implementation of the BSP tree creates a third child node for storing cells laying across split planes, the third cell may overlap the other two, but the two 'proper' nodes otherwise conform to usual BSP rules.
The advantage of this implementation is cells only ever lie in one node and mailbox testing is avoided. All BBoxes are axis aligned and a ray cast uses an efficient search strategy based on near/far nodes and rejects all BBoxes using simple tests.
For fast raytracing, 6 copies of cell lists are stored in each leaf node each list is in axis sorted order +/ x,y,z and cells are always tested in the direction of the ray dominant axis. Once an intersection is found any cell or BBox with a closest point further than the Ipoint can be instantly rejected and raytracing stops as soon as no nodes can be closer than the current best intersection point.
The addition of the 'middle' node upsets the optimal balance of the tree, but is a minor overhead during the raytrace. Each child node is contracted such that it tightly fits all cells inside it, enabling further ray/box rejections.
This class is intended for persons requiring many ray tests and is optimized for this purpose. As no cell ever lies in more than one leaf node, and parent nodes do not maintain cell lists, the memory overhead of the sorted cell lists is 6*num_cells*4 for 6 lists of ints, each num_cells in length. The memory requirement of the nodes themselves is usually of minor significance.
Subdividision is controlled by MaxCellsPerNode  any node with more than this number will be subdivided providing a good split plane can be found and the max depth is not exceeded.
The average cells per leaf will usually be around half the MaxCellsPerNode, though the middle node is usually sparsely populated and lowers the average slightly. The middle node will not be created when not needed. Subdividing down to very small cells per node is not generally suggested as then the 6 stored cell lists are effectively redundant.
Values of MaxcellsPerNode of around 16>128 depending on dataset size will usually give good results.
Cells are only sorted into 6 lists once  before tree creation, each node segments the lists and passes them down to the new child nodes whilst maintaining sorted order. This makes for an efficient subdivision strategy.
NB. The following reference has been sent to me @Article{formella1995ray, author = "Arno Formella and Christian Gill", title = "{Ray Tracing: A Quantitative Analysis and a New Practical Algorithm}", journal = "{The Visual Computer}", year = "{1995}", month = dec, pages = "{465476}", volume = "{11}", number = "{9}", publisher = "{Springer}", keywords = "{ray tracing, space subdivision, plane traversal, octree, clustering, benchmark scenes}", annote = "{We present a new method to accelerate the process of finding nearest ray–object intersections in ray tracing. The algorithm consumes an amount of memory more or less linear in the number of objects. The basic ideas can be characterized with a modified BSP–tree and plane traversal. Plane traversal is a fast linear time algorithm to find the closest intersection point in a list of bounding volumes hit by a ray. We use plane traversal at every node of the high outdegree BSP–tree. Our implementation is competitive to fast ray tracing programs. We present a benchmark suite which allows for an extensive comparison of ray tracing algorithms.}", }
Implement intersection heap for testing rays against transparent objects
This class is currently maintained by J. Biddiscombe who has specially requested that the code style not be modified to the kitware standard. Please respect the contribution of this class by keeping the style as close as possible to the author's original.
Definition at line 159 of file vtkModifiedBSPTree.h.
Standard TypeMacro.
Definition at line 165 of file vtkModifiedBSPTree.h.

protected 

overrideprotected 

static 

virtual 
Return 1 if this class is the same type of (or a subclass of) the named class.
Returns 0 otherwise. This method works in combination with vtkTypeMacro found in vtkSetGet.h.
Reimplemented from vtkAbstractCellLocator.

static 

protectedvirtual 
Reimplemented from vtkAbstractCellLocator.
vtkModifiedBSPTree* vtkModifiedBSPTree::NewInstance  (  )  const 

overridevirtual 
Methods invoked by print to print information about the object including superclasses.
Typically not called by the user (use Print() instead) but used in the hierarchical print process to combine the output of several classes.
Reimplemented from vtkAbstractCellLocator.

static 
Construct with maximum 32 cells per node.
(average 16>31)

overridevirtual 
Free tree memory.
Implements vtkLocator.

overridevirtual 
Build Tree.
Implements vtkLocator.

overridevirtual 
Generate BBox representation of Nth level.
Implements vtkLocator.

virtual 
Generate BBox representation of all leaf nodes.

overridevirtual 
Return intersection point (if any) AND the cell which was intersected by the finite line.
Uses fast treesearch BBox rejection tests.
Reimplemented from vtkAbstractCellLocator.

overridevirtual 
Return intersection point (if any) AND the cell which was intersected by the finite line.
The cell is returned as a cell id and as a generic cell.
Reimplemented from vtkAbstractCellLocator.

virtual 
Take the passed line segment and intersect it with the data set.
The return value of the function is 0 if no intersections were found. For each intersection found, the vtkPoints and CellIds objects have the relevant information added in order of intersection increasing from ray start to end. If either vtkPoints or CellIds are nullptr pointers, then no information is generated for that list.

overridevirtual 
Test a point to find if it is inside a cell.
Returns the cellId if inside or 1 if not.
Reimplemented from vtkAbstractCellLocator.
Quickly test if a point is inside the bounds of a particular cell.
Some locators cache cell bounds and this function can make use of fast access to the data.
Reimplemented from vtkAbstractCellLocator.
vtkIdListCollection* vtkModifiedBSPTree::GetLeafNodeCellInformation  (  ) 
After subdivision has completed, one may wish to query the tree to find which cells are in which leaf nodes.
This function returns a list which holds a cell Id list for each leaf node.

protected 

protectedvirtual 

protected 

protected 

protected 
virtual int vtkAbstractCellLocator::IntersectWithLine 
Return intersection point (if any) of finite line with cells contained in cell locator.
See vtkCell.h parameters documentation.
virtual int vtkAbstractCellLocator::IntersectWithLine 
Return intersection point (if any) AND the cell which was intersected by the finite line.
virtual int vtkAbstractCellLocator::IntersectWithLine 
Return intersection point (if any) AND the cell which was intersected by the finite line.
The cell is returned as a cell id and as a generic cell.
virtual int vtkAbstractCellLocator::IntersectWithLine 
Take the passed line segment and intersect it with the data set.
This method assumes that the data set is a vtkPolyData that describes a closed surface, and the intersection points that are returned in 'points' alternate between entrance points and exit points. The return value of the function is 0 if no intersections were found, 1 if point 'a0' lies inside the closed surface, or +1 if point 'a0' lies outside the closed surface. Either 'points' or 'cellIds' can be set to nullptr if you don't want to receive that information. This method is currently only implemented in vtkOBBTree.
virtual vtkIdType vtkAbstractCellLocator::FindCell 
Returns the Id of the cell containing the point, returns 1 if no cell found.
This interface uses a tolerance of zero
virtual vtkIdType vtkAbstractCellLocator::FindCell 
Find the cell containing a given point.
returns 1 if no cell found the cell parameters are copied into the supplied variables, a cell must be provided to store the information.

protected 
Definition at line 244 of file vtkModifiedBSPTree.h.

protected 
Definition at line 245 of file vtkModifiedBSPTree.h.

protected 
Definition at line 246 of file vtkModifiedBSPTree.h.

protected 
Definition at line 247 of file vtkModifiedBSPTree.h.