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222 lines
8.4 KiB
C++
222 lines
8.4 KiB
C++
/*=========================================================================
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Program: Visualization Toolkit
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Module: vtkOBBTree.h
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Copyright (c) Ken Martin, Will Schroeder, Bill Lorensen
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All rights reserved.
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See Copyright.txt or http://www.kitware.com/Copyright.htm for details.
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This software is distributed WITHOUT ANY WARRANTY; without even
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the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
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PURPOSE. See the above copyright notice for more information.
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=========================================================================*/
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/**
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* @class vtkOBBTree
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* @brief generate oriented bounding box (OBB) tree
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*
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* vtkOBBTree is an object to generate oriented bounding box (OBB) trees.
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* An oriented bounding box is a bounding box that does not necessarily line
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* up along coordinate axes. The OBB tree is a hierarchical tree structure
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* of such boxes, where deeper levels of OBB confine smaller regions of space.
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*
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* To build the OBB, a recursive, top-down process is used. First, the root OBB
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* is constructed by finding the mean and covariance matrix of the cells (and
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* their points) that define the dataset. The eigenvectors of the covariance
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* matrix are extracted, giving a set of three orthogonal vectors that define
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* the tightest-fitting OBB. To create the two children OBB's, a split plane
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* is found that (approximately) divides the number cells in half. These are
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* then assigned to the children OBB's. This process then continues until
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* the MaxLevel ivar limits the recursion, or no split plane can be found.
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*
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* A good reference for OBB-trees is Gottschalk & Manocha in Proceedings of
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* Siggraph `96.
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*
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* @warning
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* Since this algorithms works from a list of cells, the OBB tree will only
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* bound the "geometry" attached to the cells if the convex hull of the
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* cells bounds the geometry.
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*
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* @warning
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* Long, skinny cells (i.e., cells with poor aspect ratio) may cause
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* unsatisfactory results. This is due to the fact that this is a top-down
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* implementation of the OBB tree, requiring that one or more complete cells
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* are contained in each OBB. This requirement makes it hard to find good
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* split planes during the recursion process. A bottom-up implementation would
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* go a long way to correcting this problem.
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*
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* @sa
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* vtkLocator vtkCellLocator vtkPointLocator
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*/
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#ifndef vtkOBBTree_h
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#define vtkOBBTree_h
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#include "vtkFiltersGeneralModule.h" // For export macro
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#include "vtkAbstractCellLocator.h"
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class vtkMatrix4x4;
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// Special class defines node for the OBB tree
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//
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//
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class VTKFILTERSGENERAL_EXPORT vtkOBBNode { //;prevent man page generation
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public:
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vtkOBBNode();
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~vtkOBBNode();
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double Corner[3]; //center point of this node
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double Axes[3][3]; //the axes defining the OBB - ordered from long->short
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vtkOBBNode *Parent; //parent node; NULL if root
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vtkOBBNode **Kids; //two children of this node; NULL if leaf
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vtkIdList *Cells; //list of cells in node
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void DebugPrintTree( int level, double *leaf_vol, int *minCells,
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int *maxCells );
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private:
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vtkOBBNode(const vtkOBBNode& other) VTK_DELETE_FUNCTION;
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vtkOBBNode& operator=(const vtkOBBNode& rhs) VTK_DELETE_FUNCTION;
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};
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//
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class VTKFILTERSGENERAL_EXPORT vtkOBBTree : public vtkAbstractCellLocator
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{
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public:
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vtkTypeMacro(vtkOBBTree,vtkAbstractCellLocator);
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void PrintSelf(ostream& os, vtkIndent indent) VTK_OVERRIDE;
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/**
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* Construct with automatic computation of divisions, averaging
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* 25 cells per octant.
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*/
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static vtkOBBTree *New();
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// Re-use any superclass signatures that we don't override.
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using vtkAbstractCellLocator::IntersectWithLine;
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/**
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* Take the passed line segment and intersect it with the data set.
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* This method assumes that the data set is a vtkPolyData that describes
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* a closed surface, and the intersection points that are returned in
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* 'points' alternate between entrance points and exit points.
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* The return value of the function is 0 if no intersections were found,
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* -1 if point 'a0' lies inside the closed surface, or +1 if point 'a0'
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* lies outside the closed surface.
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* Either 'points' or 'cellIds' can be set to NULL if you don't want
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* to receive that information.
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*/
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int IntersectWithLine(const double a0[3], const double a1[3],
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vtkPoints *points, vtkIdList *cellIds) VTK_OVERRIDE;
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/**
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* Return the first intersection of the specified line segment with
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* the OBB tree, as well as information about the cell which the
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* line segment intersected.
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*/
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int IntersectWithLine(double a0[3], double a1[3], double tol,
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double& t, double x[3], double pcoords[3],
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int &subId, vtkIdType &cellId, vtkGenericCell *cell) VTK_OVERRIDE;
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/**
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* Compute an OBB from the list of points given. Return the corner point
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* and the three axes defining the orientation of the OBB. Also return
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* a sorted list of relative "sizes" of axes for comparison purposes.
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*/
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static void ComputeOBB(vtkPoints *pts, double corner[3], double max[3],
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double mid[3], double min[3], double size[3]);
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/**
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* Compute an OBB for the input dataset using the cells in the data.
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* Return the corner point and the three axes defining the orientation
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* of the OBB. Also return a sorted list of relative "sizes" of axes for
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* comparison purposes.
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*/
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void ComputeOBB(vtkDataSet *input, double corner[3], double max[3],
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double mid[3], double min[3], double size[3]);
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/**
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* Determine whether a point is inside or outside the data used to build
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* this OBB tree. The data must be a closed surface vtkPolyData data set.
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* The return value is +1 if outside, -1 if inside, and 0 if undecided.
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*/
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int InsideOrOutside(const double point[3]);
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/**
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* Returns true if nodeB and nodeA are disjoint after optional
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* transformation of nodeB with matrix XformBtoA
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*/
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int DisjointOBBNodes( vtkOBBNode *nodeA, vtkOBBNode *nodeB,
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vtkMatrix4x4 *XformBtoA );
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/**
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* Returns true if line intersects node.
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*/
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int LineIntersectsNode( vtkOBBNode *pA, double b0[3], double b1[3] );
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/**
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* Returns true if triangle (optionally transformed) intersects node.
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*/
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int TriangleIntersectsNode( vtkOBBNode *pA,
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double p0[3], double p1[3],
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double p2[3], vtkMatrix4x4 *XformBtoA );
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/**
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* For each intersecting leaf node pair, call function.
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* OBBTreeB is optionally transformed by XformBtoA before testing.
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*/
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int IntersectWithOBBTree( vtkOBBTree *OBBTreeB, vtkMatrix4x4 *XformBtoA,
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int(*function)( vtkOBBNode *nodeA,
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vtkOBBNode *nodeB,
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vtkMatrix4x4 *Xform,
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void *arg ),
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void *data_arg );
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//@{
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/**
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* Satisfy locator's abstract interface, see vtkLocator.
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*/
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void FreeSearchStructure() VTK_OVERRIDE;
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void BuildLocator() VTK_OVERRIDE;
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//@}
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/**
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* Create polygonal representation for OBB tree at specified level. If
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* level < 0, then the leaf OBB nodes will be gathered. The aspect ratio (ar)
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* and line diameter (d) are used to control the building of the
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* representation. If a OBB node edge ratio's are greater than ar, then the
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* dimension of the OBB is collapsed (OBB->plane->line). A "line" OBB will be
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* represented either as two crossed polygons, or as a line, depending on
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* the relative diameter of the OBB compared to the diameter (d).
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*/
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void GenerateRepresentation(int level, vtkPolyData *pd) VTK_OVERRIDE;
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protected:
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vtkOBBTree();
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~vtkOBBTree() VTK_OVERRIDE;
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// Compute an OBB from the list of cells given. This used to be
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// public but should not have been. A public call has been added
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// so that the functionality can be accessed.
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void ComputeOBB(vtkIdList *cells, double corner[3], double max[3],
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double mid[3], double min[3], double size[3]);
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vtkOBBNode *Tree;
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void BuildTree(vtkIdList *cells, vtkOBBNode *parent, int level);
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vtkPoints *PointsList;
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int *InsertedPoints;
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int OBBCount;
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void DeleteTree(vtkOBBNode *OBBptr);
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void GeneratePolygons(vtkOBBNode *OBBptr, int level, int repLevel,
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vtkPoints* pts, vtkCellArray *polys);
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private:
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vtkOBBTree(const vtkOBBTree&) VTK_DELETE_FUNCTION;
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void operator=(const vtkOBBTree&) VTK_DELETE_FUNCTION;
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};
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#endif
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