#ifndef _ViewCellBsp_H__
#define _ViewCellBsp_H__

#include "Mesh.h"
class ViewCell;
class Plane3;
//class Mesh;

//namespace GtpVisibilityPreprocessor {
  
class BSPInterior;


  /**
     BSPNode abstract class serving for interior and leaf node implementation
  */
  class BSPNode 
  {
  public:
	  /** Determines whether this node is a leaf or not
	  @return true if leaf
	  */
	  virtual bool IsLeaf() const = 0;
    
	  /** Determines whether this node is a root
	  @return true if root
	  */
	  virtual bool IsRoot() const;

  protected:

	  /// parent of this node
	  BSPInterior *mParent;
  };

  /** BSP interior node implementation */
  class BSPInterior : public BSPNode 
  {   
  public:
	  /** @return false since it is an interior node */
	  bool IsLeaf() const;

	  BSPNode *GetBack() {return mBack;}
	  BSPNode *GetFront() {return mFront;}

	  void ReplaceChildLink(BSPNode *oldChild, BSPNode *newChild);
	  void SetupChildLinks(BSPNode *b, BSPNode *f);

  protected:
		
	  /// Splitting plane corresponding to this node
	  Plane3 mPlane;
	  /// back node
	  BSPNode *mBack;
	  /// front node
	  BSPNode *mFront;
  };
  
  
  /** BSP leaf node implementation */
  class BSPLeaf : public BSPNode 
  {
  public:
	  BSPLeaf(ViewCell *viewCell = NULL);
    
	  /** @return true since it is an interior node */
	  bool IsLeaf() const;

  protected:
   
	  /// polygonal representation of this viewcell
	  /// if NULL this note does not correspond to feasible viewcell
	  ViewCell *mViewCell;
  };
  
  /** Implementation of the ViewCell BSP tree */
  class BSPTree 
  {
  public:
	  struct BSPTraversalData
	  {  
		  BSPNode *mNode;
		  BSPInterior *mParent;

		  Mesh mViewCell;
		  int mDepth;
		      
		  BSPTraversalData() {}
		  BSPTraversalData(BSPNode *n, BSPInterior *p, const Mesh &m, const int d): 
		  mNode(n), mParent(p), mViewCell(m), mDepth(d) {}
      };
	 
	  /** Constructor takes a pointer to the cell corresponding to the whole
	  viewspace */
	  BSPTree(ViewCell *cell);
        
  protected:
	   
	  Plane3 *SelectPlane(Mesh *viewcell);
	   void Subdivide();
	   
	   BSPNode *SubdivideNode(BSPLeaf *leaf, BSPInterior *parent, 
							 Mesh *viewCell, const int depth, 
							 Mesh &frontPolys, Mesh &backPolys);

	  /// Pointer to the root of the tree
	  BSPNode *mRoot;
	  /// Pointer to the root cell of the viewspace
	  ViewCell *mRootCell;
  };
  
//}; // GtpVisibilityPreprocessor

#endif