CrystalSpace

Public API Reference

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 
00062 struct iKDTreeUserData : public virtual iBase
00063 {
00064   SCF_INTERFACE (iKDTreeUserData, 0, 0, 1);
00065 };
00066 
00089 typedef bool (csKDTreeVisitFunc)(csKDTree* treenode, void* userdata,
00090         uint32 timestamp, uint32& frustum_mask);
00091 
00095 class CS_CRYSTALSPACE_EXPORT csKDTreeChild
00096 {
00097 private:
00098   friend class csKDTree;
00099 
00100   csBox3 bbox;
00101   void* object;                 // Pointer back to the original object.
00102   csKDTree** leafs;             // Leafs that contain this object.
00103   int num_leafs;
00104   int max_leafs;
00105 
00106 public:
00107   uint32 timestamp;             // Timestamp of last visit to this child.
00108 
00109 public:
00110   csKDTreeChild ();
00111   ~csKDTreeChild ();
00112 
00114   void AddLeaf (csKDTree* leaf);
00116   void RemoveLeaf (int idx);
00118   void RemoveLeaf (csKDTree* leaf);
00125   void ReplaceLeaf (csKDTree* old_leaf, csKDTree* new_leaf);
00126 
00130   int FindLeaf (csKDTree* leaf);
00131 
00135   inline const csBox3& GetBBox () const { return bbox; }
00136 
00140   inline void* GetObject () const { return object; }
00141 };
00142 
00143 enum
00144 {
00145   CS_KDTREE_AXISINVALID = -1,
00146   CS_KDTREE_AXISX = 0,
00147   CS_KDTREE_AXISY = 1,
00148   CS_KDTREE_AXISZ = 2
00149 };
00150 
00167 class CS_CRYSTALSPACE_EXPORT csKDTree :
00168   public scfImplementation1<csKDTree, iDebugHelper>
00169 {
00170 public:
00171   // This is used for debugging.
00172   csRef<iKDTreeObjectDescriptor> descriptor;
00173   void DumpObject (csKDTreeChild* object, const char* msg);
00174   void DumpNode ();
00175   void DumpNode (const char* msg);
00176   static void DebugExit ();
00177 
00178 private:
00179   csKDTree* child1;             // If child1 is not 0 then child2 will
00180   csKDTree* child2;             // also be not 0.
00181   csKDTree* parent;             // 0 if this is the root.
00182 
00183   csRef<iKDTreeUserData> userobject; // An optional user object for this node.
00184 
00185   csBox3 node_bbox;             // Bbox of the node itself.
00186 
00187   int split_axis;               // One of CS_KDTREE_AXIS?
00188   float split_location;         // Where is the split?
00189 
00190   // Objects in this node. If this node also has children (child1
00191   // and child2) then the objects here have to be moved to these
00192   // children. The 'Distribute()' function will do that.
00193   csKDTreeChild** objects;
00194   int num_objects;
00195   int max_objects;
00196 
00197   // Estimate of the total number of objects in this tree including children.
00198   int estimate_total_objects;
00199 
00200   // Minimum amount of objects in this tree before we consider splitting.
00201   int min_split_objects;
00202 
00203   // Disallow Distribute().
00204   // If this flag > 0 it means that we cannot find a good split
00205   // location for the current list of objects. So in that case we don't
00206   // split at all and set this flag to DISALLOW_DISTRIBUTE_TIME so
00207   // that we will no longer attempt to distribute for a while. Whenever
00208   // objects are added or removed to this node this flag will be decreased
00209   // so that when it becomes 0 we can make a new Distribute() attempt can
00210   // be made. This situation should be rare though.
00211 #define DISALLOW_DISTRIBUTE_TIME 20
00212   int disallow_distribute;
00213 
00214   // Current timestamp we are using for Front2Back(). Objects that
00215   // have the same timestamp are already visited during Front2Back().
00216   static uint32 global_timestamp;
00217 
00219   void AddObject (csKDTreeChild* obj);
00221   void RemoveObject (int idx);
00223   int FindObject (csKDTreeChild* obj);
00224 
00228   void AddObjectInt (csKDTreeChild* obj);
00229 
00240   float FindBestSplitLocation (int axis, float& split_loc);
00241 
00247   void DistributeLeafObjects ();
00248 
00255   void Front2Back (const csVector3& pos, csKDTreeVisitFunc* func,
00256         void* userdata, uint32 cur_timestamp, uint32 frustum_mask);
00257 
00264   void TraverseRandom (csKDTreeVisitFunc* func,
00265         void* userdata, uint32 cur_timestamp, uint32 frustum_mask);
00266 
00270   void ResetTimestamps ();
00271 
00275   void FlattenTo (csKDTree* node);
00276 
00277 public:
00279   csKDTree ();
00281   virtual ~csKDTree ();
00283   void SetParent (csKDTree* p) { parent = p; }
00284 
00286   void SetObjectDescriptor (iKDTreeObjectDescriptor* descriptor)
00287   {
00288     csKDTree::descriptor = descriptor;
00289   }
00290 
00295   void SetMinimumSplitAmount (int m) { min_split_objects = m; }
00296 
00298   void Clear ();
00299 
00301   inline iKDTreeUserData* GetUserObject () const { return userobject; }
00302 
00308   void SetUserObject (iKDTreeUserData* userobj);
00309 
00317   csKDTreeChild* AddObject (const csBox3& bbox, void* object);
00318 
00323   void UnlinkObject (csKDTreeChild* object);
00324 
00329   void RemoveObject (csKDTreeChild* object);
00330 
00334   void MoveObject (csKDTreeChild* object, const csBox3& new_bbox);
00335 
00342   void Distribute ();
00343 
00347   void FullDistribute ();
00348 
00354   void Flatten ();
00355 
00361   void TraverseRandom (csKDTreeVisitFunc* func,
00362         void* userdata, uint32 frustum_mask);
00363 
00370   void Front2Back (const csVector3& pos, csKDTreeVisitFunc* func,
00371         void* userdata, uint32 frustum_mask);
00372 
00380   uint32 NewTraversal ();
00381 
00385   inline csKDTree* GetChild1 () const { return child1; }
00386 
00390   inline csKDTree* GetChild2 () const { return child2; }
00391 
00395   inline int GetObjectCount () const { return num_objects; }
00396 
00403   inline int GetEstimatedObjectCount () { return estimate_total_objects; }
00404 
00408   inline csKDTreeChild** GetObjects () const { return objects; }
00409 
00414   inline const csBox3& GetNodeBBox () const { return node_bbox; }
00415 
00416   // Debugging functions.
00417   bool Debug_CheckTree (csString& str);
00418   void Debug_Dump (csString& str, int indent);
00419   void Debug_Statistics (int& tot_objects,
00420         int& tot_nodes, int& tot_leaves, int depth, int& max_depth,
00421         float& balance_quality);
00422   csPtr<iString> Debug_Statistics ();
00423   csTicks Debug_Benchmark (int num_iterations);
00424 
00425   virtual int GetSupportedTests () const
00426   {
00427     return CS_DBGHELP_STATETEST |
00428       CS_DBGHELP_TXTDUMP | CS_DBGHELP_BENCHMARK;
00429   }
00430 
00431   virtual csPtr<iString> StateTest ()
00432   {
00433     scfString* rc = new scfString ();
00434     if (!Debug_CheckTree (rc->GetCsString ()))
00435       return csPtr<iString> (rc);
00436     delete rc;
00437     return 0;
00438   }
00439 
00440   virtual csTicks Benchmark (int num_iterations)
00441   {
00442     return Debug_Benchmark (num_iterations);
00443   }
00444 
00445   virtual csPtr<iString> Dump ()
00446   {
00447     scfString* rc = new scfString ();
00448     Debug_Dump (rc->GetCsString (), 0);
00449     return csPtr<iString> (rc);
00450   }
00451 
00452   virtual void Dump (iGraphics3D* /*g3d*/) { }
00453   virtual bool DebugCommand (const char*) { return false; }
00454 };
00455 
00458 #endif // __CS_KDTREE_H__
00459 

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