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# csgeom/kdtree.h

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    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 "csextern.h"
    00023
    00024 #include "csgeom/box.h"
    00025
    00026 #include "csutil/blockallocator.h"
    00027 #include "csutil/ref.h"
    00028 #include "csutil/scfstr.h"
    00029 #include "csutil/scf_implementation.h"
    00030
    00031 #include "iutil/dbghelp.h"
    00032
    00039 struct iGraphics3D;
    00040 struct iString;
    00041 class csKDTree;
    00042 class csKDTreeChild;
    00043
    00050 struct iKDTreeObjectDescriptor : public virtual iBase
    00051 {
    00052   SCF_INTERFACE (iKDTreeObjectDescriptor, 0, 0, 1);
    00053
    00054   virtual csPtr<iString> DescribeObject (csKDTreeChild* child) = 0;
    00055 };
    00056
    00079 typedef bool (csKDTreeVisitFunc)(csKDTree* treenode, void* userdata,
    00080         uint32 timestamp, uint32& frustum_mask);
    00081
    00085 class CS_CRYSTALSPACE_EXPORT csKDTreeChild
    00086 {
    00087 private:
    00088   friend class csKDTree;
    00089
    00090   csBox3 bbox;
    00091   void* object;                 // Pointer back to the original object.
    00092   csKDTree** leafs;             // Leafs that contain this object.
    00093   int num_leafs;
    00094   int max_leafs;
    00095
    00096 public:
    00097   uint32 timestamp;             // Timestamp of last visit to this child.
    00098
    00099 public:
    00100   csKDTreeChild ();
    00101   ~csKDTreeChild ();
    00102
    00104   void AddLeaf (csKDTree* leaf);
    00106   void RemoveLeaf (int idx);
    00108   void RemoveLeaf (csKDTree* leaf);
    00115   void ReplaceLeaf (csKDTree* old_leaf, csKDTree* new_leaf);
    00116
    00120   int FindLeaf (csKDTree* leaf);
    00121
    00125   inline const csBox3& GetBBox () const { return bbox; }
    00126
    00130   inline void* GetObject () const { return object; }
    00131 };
    00132
    00133 enum
    00134 {
    00135   CS_KDTREE_AXISINVALID = -1,
    00136   CS_KDTREE_AXISX = 0,
    00137   CS_KDTREE_AXISY = 1,
    00138   CS_KDTREE_AXISZ = 2
    00139 };
    00140
    00157 class CS_CRYSTALSPACE_EXPORT csKDTree :
    00158   public scfImplementation1<csKDTree, iDebugHelper>
    00159 {
    00160 public:
    00161   // This is used for debugging.
    00162   csRef<iKDTreeObjectDescriptor> descriptor;
    00163   void DumpObject (csKDTreeChild* object, const char* msg);
    00164   void DumpNode ();
    00165   void DumpNode (const char* msg);
    00166   void DebugExit ();
    00167
    00168 private:
    00169   static csBlockAllocator<csKDTree> tree_nodes;
    00170   static csBlockAllocator<csKDTreeChild> tree_children;
    00171
    00172   csKDTree* child1;             // If child1 is not 0 then child2 will
    00173   csKDTree* child2;             // also be not 0.
    00174   csKDTree* parent;             // 0 if this is the root.
    00175
    00176   csRef<iBase> userobject;      // An optional user object for this node.
    00177
    00178   csBox3 node_bbox;             // Bbox of the node itself.
    00179
    00180   int split_axis;               // One of CS_KDTREE_AXIS?
    00181   float split_location;         // Where is the split?
    00182
    00183   // Objects in this node. If this node also has children (child1
    00184   // and child2) then the objects here have to be moved to these
    00185   // children. The 'Distribute()' function will do that.
    00186   csKDTreeChild** objects;
    00187   int num_objects;
    00188   int max_objects;
    00189
    00190   // Estimate of the total number of objects in this tree including children.
    00191   int estimate_total_objects;
    00192
    00193   // Disallow Distribute().
    00194   // If this flag > 0 it means that we cannot find a good split
    00195   // location for the current list of objects. So in that case we don't
    00196   // split at all and set this flag to DISALLOW_DISTRIBUTE_TIME so
    00197   // that we will no longer attempt to distribute for a while. Whenever
    00198   // objects are added or removed to this node this flag will be decreased
    00199   // so that when it becomes 0 we can make a new Distribute() attempt can
    00200   // be made. This situation should be rare though.
    00201 #define DISALLOW_DISTRIBUTE_TIME 20
    00202   int disallow_distribute;
    00203
    00204   // Current timestamp we are using for Front2Back(). Objects that
    00205   // have the same timestamp are already visited during Front2Back().
    00206   static uint32 global_timestamp;
    00207
    00209   void AddObject (csKDTreeChild* obj);
    00211   void RemoveObject (int idx);
    00213   int FindObject (csKDTreeChild* obj);
    00214
    00218   void AddObject (const csBox3& bbox, csKDTreeChild* obj);
    00219
    00230   float FindBestSplitLocation (int axis, float& split_loc);
    00231
    00237   void DistributeLeafObjects ();
    00238
    00245   void Front2Back (const csVector3& pos, csKDTreeVisitFunc* func,
    00246         void* userdata, uint32 cur_timestamp, uint32 frustum_mask);
    00247
    00254   void TraverseRandom (csKDTreeVisitFunc* func,
    00255         void* userdata, uint32 cur_timestamp, uint32 frustum_mask);
    00256
    00260   void ResetTimestamps ();
    00261
    00265   void FlattenTo (csKDTree* node);
    00266
    00267 public:
    00269   csKDTree ();
    00271   virtual ~csKDTree ();
    00273   void SetParent (csKDTree* p) { parent = p; }
    00274
    00276   void SetObjectDescriptor (iKDTreeObjectDescriptor* descriptor)
    00277   {
    00278     csKDTree::descriptor = descriptor;
    00279   }
    00280
    00282   void Clear ();
    00283
    00285   inline iBase* GetUserObject () const { return userobject; }
    00286
    00292   void SetUserObject (iBase* userobj);
    00293
    00301   csKDTreeChild* AddObject (const csBox3& bbox, void* object);
    00302
    00307   void UnlinkObject (csKDTreeChild* object);
    00308
    00313   void RemoveObject (csKDTreeChild* object);
    00314
    00318   void MoveObject (csKDTreeChild* object, const csBox3& new_bbox);
    00319
    00326   void Distribute ();
    00327
    00331   void FullDistribute ();
    00332
    00338   void Flatten ();
    00339
    00345   void TraverseRandom (csKDTreeVisitFunc* func,
    00346         void* userdata, uint32 frustum_mask);
    00347
    00354   void Front2Back (const csVector3& pos, csKDTreeVisitFunc* func,
    00355         void* userdata, uint32 frustum_mask);
    00356
    00364   uint32 NewTraversal ();
    00365
    00369   inline csKDTree* GetChild1 () const { return child1; }
    00370
    00374   inline csKDTree* GetChild2 () const { return child2; }
    00375
    00379   inline int GetObjectCount () const { return num_objects; }
    00380
    00387   inline int GetEstimatedObjectCount () { return estimate_total_objects; }
    00388
    00392   inline csKDTreeChild** GetObjects () const { return objects; }
    00393
    00398   inline const csBox3& GetNodeBBox () const { return node_bbox; }
    00399
    00400   // Debugging functions.
    00401   bool Debug_CheckTree (csString& str);
    00402   csPtr<iString> Debug_UnitTest ();
    00403   void Debug_Dump (csString& str, int indent);
    00404   void Debug_Statistics (int& tot_objects,
    00405         int& tot_nodes, int& tot_leaves, int depth, int& max_depth,
    00406         float& balance_quality);
    00407   csPtr<iString> Debug_Statistics ();
    00408   csTicks Debug_Benchmark (int num_iterations);
    00409
    00410   virtual int GetSupportedTests () const
    00411   {
    00412     return CS_DBGHELP_UNITTEST | CS_DBGHELP_STATETEST |
    00413       CS_DBGHELP_TXTDUMP | CS_DBGHELP_BENCHMARK;
    00414   }
    00415
    00416   virtual csPtr<iString> UnitTest ()
    00417   {
    00418     return Debug_UnitTest ();
    00419   }
    00420
    00421   virtual csPtr<iString> StateTest ()
    00422   {
    00423     scfString* rc = new scfString ();
    00424     if (!Debug_CheckTree (rc->GetCsString ()))
    00425       return csPtr<iString> (rc);
    00426     delete rc;
    00427     return 0;
    00428   }
    00429
    00430   virtual csTicks Benchmark (int num_iterations)
    00431   {
    00432     return Debug_Benchmark (num_iterations);
    00433   }
    00434
    00435   virtual csPtr<iString> Dump ()
    00436   {
    00437     scfString* rc = new scfString ();
    00438     Debug_Dump (rc->GetCsString (), 0);
    00439     return csPtr<iString> (rc);
    00440   }
    00441
    00442   virtual void Dump (iGraphics3D* /*g3d*/) { }
    00443   virtual bool DebugCommand (const char*) { return false; }
    00444 };
    00445
    00448 #endif // __CS_KDTREE_H__
    00449