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csgeom/kdtree.h

00001 /*
00002     Copyright (C) 2002 by Jorrit Tyberghein
00003 
00004     This library is free software; you can redistribute it and/or
00005     modify it under the terms of the GNU Library General Public
00006     License as published by the Free Software Foundation; either
00007     version 2 of the License, or (at your option) any later version.
00008 
00009     This library is distributed in the hope that it will be useful,
00010     but WITHOUT ANY WARRANTY; without even the implied warranty of
00011     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
00012     Library General Public License for more details.
00013 
00014     You should have received a copy of the GNU Library General Public
00015     License along with this library; if not, write to the Free
00016     Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
00017 */
00018 
00019 #ifndef __CS_KDTREE_H__
00020 #define __CS_KDTREE_H__
00021 
00022 #include "csgeom/box.h"
00023 #include "csgeom/vector2.h"
00024 #include "csgeom/math2d.h"
00025 #include "csutil/scfstr.h"
00026 #include "csutil/blockallocator.h"
00027 #include "iutil/dbghelp.h"
00028 
00029 struct iGraphics3D;
00030 class csKDTree;
00031 
00054 typedef bool (csKDTreeVisitFunc)(csKDTree* treenode, void* userdata,
00055         uint32 timestamp, uint32& frustum_mask);
00056 
00060 class csKDTreeChild
00061 {
00062 private:
00063   friend class csKDTree;
00064 
00065   csBox3 bbox;
00066   void* object;                 // Pointer back to the original object.
00067   csKDTree** leafs;             // Leafs that contain this object.
00068   int num_leafs;
00069   int max_leafs;
00070 
00071 public:
00072   uint32 timestamp;             // Timestamp of last visit to this child.
00073 
00074 public:
00075   csKDTreeChild ();
00076   ~csKDTreeChild ();
00077 
00079   void AddLeaf (csKDTree* leaf);
00081   void RemoveLeaf (int idx);
00083   void RemoveLeaf (csKDTree* leaf);
00090   void ReplaceLeaf (csKDTree* old_leaf, csKDTree* new_leaf);
00091 
00095   int FindLeaf (csKDTree* leaf);
00096 
00100   const csBox3& GetBBox () const { return bbox; }
00101 
00105   void* GetObject () const { return object; }
00106 };
00107 
00108 #define CS_KDTREE_AXISINVALID -1
00109 #define CS_KDTREE_AXISX 0
00110 #define CS_KDTREE_AXISY 1
00111 #define CS_KDTREE_AXISZ 2
00112 
00129 class csKDTree : public iBase
00130 {
00131 private:
00132   static csBlockAllocator<csKDTree> tree_nodes;
00133   static csBlockAllocator<csKDTreeChild> tree_children;
00134 
00135   csKDTree* child1;             // If child1 is not 0 then child2 will
00136   csKDTree* child2;             // also be not 0.
00137   csKDTree* parent;             // 0 if this is the root.
00138 
00139   iBase* userobject;            // An optional user object for this node.
00140 
00141   csBox3 node_bbox;             // Bbox of the node itself.
00142 
00143   int split_axis;               // One of CS_KDTREE_AXIS?
00144   float split_location;         // Where is the split?
00145 
00146   // Objects in this node. If this node also has children (child1
00147   // and child2) then the objects here have to be moved to these
00148   // children. The 'Distribute()' function will do that.
00149   csKDTreeChild** objects;
00150   int num_objects;
00151   int max_objects;
00152 
00153   // Estimate of the total number of objects in this tree including children.
00154   int estimate_total_objects;
00155 
00156   // Disallow Distribute().
00157   // If this flag is true it means that we cannot find a good split
00158   // location for the current list of objects. So in that case we don't
00159   // split at all and set this flag to true so that we will no longer
00160   // attempt to distribute. Whenever objects are added or removed to this
00161   // node this flag will be set to false again so that a new Distribute()
00162   // attempt can be made. This situation should be rare though.
00163   bool disallow_distribute;
00164 
00165   // Current timestamp we are using for Front2Back(). Objects that
00166   // have the same timestamp are already visited during Front2Back().
00167   static uint32 global_timestamp;
00168 
00170   void AddObject (csKDTreeChild* obj);
00172   void RemoveObject (int idx);
00174   int FindObject (csKDTreeChild* obj);
00175 
00179   void AddObject (const csBox3& bbox, csKDTreeChild* obj);
00180 
00191   float FindBestSplitLocation (int axis, float& split_loc);
00192 
00198   void DistributeLeafObjects ();
00199 
00206   bool Front2Back (const csVector3& pos, csKDTreeVisitFunc* func,
00207         void* userdata, uint32 cur_timestamp, uint32 frustum_mask);
00208 
00212   void ResetTimestamps ();
00213 
00217   void FlattenTo (csKDTree* node);
00218 
00219 public:
00221   csKDTree ();
00223   virtual ~csKDTree ();
00225   void SetParent (csKDTree* p) { parent = p; }
00226 
00228   void Clear ();
00229 
00230   SCF_DECLARE_IBASE;
00231 
00233   iBase* GetUserObject () const { return userobject; }
00234 
00240   void SetUserObject (iBase* userobj);
00241 
00249   csKDTreeChild* AddObject (const csBox3& bbox, void* object);
00250 
00255   void UnlinkObject (csKDTreeChild* object);
00256 
00261   void RemoveObject (csKDTreeChild* object);
00262 
00266   void MoveObject (csKDTreeChild* object, const csBox3& new_bbox);
00267 
00274   void Distribute ();
00275 
00279   void FullDistribute ();
00280 
00286   void Flatten ();
00287 
00294   void Front2Back (const csVector3& pos, csKDTreeVisitFunc* func,
00295         void* userdata, uint32 frustum_mask);
00296 
00300   int GetObjectCount () const { return num_objects; }
00301 
00308   int GetEstimatedObjectCount () { return estimate_total_objects; }
00309 
00313   csKDTreeChild** GetObjects () const { return objects; }
00314 
00319   const csBox3& GetNodeBBox () const { return node_bbox; }
00320 
00321   // Debugging functions.
00322   bool Debug_CheckTree (csString& str);
00323   csPtr<iString> Debug_UnitTest ();
00324   void Debug_Dump (csString& str, int indent);
00325   void Debug_Statistics (int& tot_objects,
00326         int& tot_nodes, int& tot_leaves, int depth, int& max_depth,
00327         float& balance_quality);
00328   csPtr<iString> Debug_Statistics ();
00329   csTicks Debug_Benchmark (int num_iterations);
00330 
00331   struct DebugHelper : public iDebugHelper
00332   {
00333     SCF_DECLARE_EMBEDDED_IBASE (csKDTree);
00334     virtual int GetSupportedTests () const
00335     {
00336       return CS_DBGHELP_UNITTEST | CS_DBGHELP_STATETEST |
00337         CS_DBGHELP_TXTDUMP | CS_DBGHELP_BENCHMARK;
00338     }
00339     virtual csPtr<iString> UnitTest ()
00340     {
00341       return scfParent->Debug_UnitTest ();
00342     }
00343     virtual csPtr<iString> StateTest ()
00344     {
00345       scfString* rc = new scfString ();
00346       if (!scfParent->Debug_CheckTree (rc->GetCsString ()))
00347         return csPtr<iString> (rc);
00348       delete rc;
00349       return 0;
00350     }
00351     virtual csTicks Benchmark (int num_iterations)
00352     {
00353       return scfParent->Debug_Benchmark (num_iterations);
00354     }
00355     virtual csPtr<iString> Dump ()
00356     {
00357       scfString* rc = new scfString ();
00358       scfParent->Debug_Dump (rc->GetCsString (), 0);
00359       return csPtr<iString> (rc);
00360     }
00361     virtual void Dump (iGraphics3D* /*g3d*/)
00362     {
00363     }
00364     virtual bool DebugCommand (const char*)
00365     {
00366       return false;
00367     }
00368   } scfiDebugHelper;
00369 };
00370 
00371 #endif // __CS_KDTREE_H__
00372 

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