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00001 
+00007 /* Copyright, 2001 Nevrax Ltd.
+00008  *
+00009  * This file is part of NEVRAX NEL.
+00010  * NEVRAX NEL is free software; you can redistribute it and/or modify
+00011  * it under the terms of the GNU General Public License as published by
+00012  * the Free Software Foundation; either version 2, or (at your option)
+00013  * any later version.
+00014 
+00015  * NEVRAX NEL is distributed in the hope that it will be useful, but
+00016  * WITHOUT ANY WARRANTY; without even the implied warranty of
+00017  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+00018  * General Public License for more details.
+00019 
+00020  * You should have received a copy of the GNU General Public License
+00021  * along with NEVRAX NEL; see the file COPYING. If not, write to the
+00022  * Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
+00023  * MA 02111-1307, USA.
+00024  */
+00025 
+00026 #include "std3d.h"
+00027 
+00028 #include "3d/quad_grid_clip_cluster.h"
+00029 
+00030 
+00031 using namespace NLMISC;
+00032 using namespace std;
+00033 
+00034 
+00035 namespace NL3D {
+00036 
+00037 
+00038 // ***************************************************************************
+00039 void            CQuadGridClipCluster::registerBasic()
+00040 {
+00041         CMOT::registerModel( QuadGridClipClusterId, 0, CQuadGridClipCluster::creator);
+00042         CMOT::registerObs( ClipTravId, QuadGridClipClusterId, CQuadGridClipClusterClipObs::creator );
+00043 }
+00044 
+00045 
+00046 // ***************************************************************************
+00047 void            CQuadGridClipCluster::extendCluster(const NLMISC::CAABBox &worldBBox)
+00048 {
+00049         if(_Empty)
+00050         {
+00051                 _Empty= false;
+00052                 _BBox= worldBBox;
+00053         }
+00054         else
+00055         {
+00056                 // extend the bbox with 2 corners of the incoming bbox (sufficient for an AABBox).
+00057                 _BBox.extend( worldBBox.getCenter() + worldBBox.getHalfSize() );
+00058                 _BBox.extend( worldBBox.getCenter() - worldBBox.getHalfSize() );
+00059         }
+00060 
+00061         // update _Radius
+00062         _Radius= _BBox.getRadius();
+00063 }
+00064 
+00065 
+00066 // ***************************************************************************
+00067 void            CQuadGridClipCluster::update()
+00068 {
+00069         // never need to update, so unlink me from ValidateList.
+00070         unlinkFromValidateList();
+00071 }
+00072 
+00073 
+00074 // ***************************************************************************
+00075 CQuadGridClipClusterClipObs::CQuadGridClipClusterClipObs()
+00076 {
+00077         _LastClipWasDistMaxClip= false;
+00078         _LastClipWasFrustumClip= false;
+00079 }
+00080 
+00081 // ***************************************************************************
+00082 void            CQuadGridClipClusterClipObs::traverse(IObs *caller)
+00083 {
+00084         CQuadGridClipCluster    *cluster= (CQuadGridClipCluster*)Model;
+00085         CClipTrav                       *clipTrav= (CClipTrav*)Trav;
+00086 
+00087         // if empty, just return (not visible at all).
+00088         if(cluster->_Empty)
+00089         {
+00090                 /* reset cache, to be sure that any instances added to this cluster later will 
+00091                         be correctly updated if a clip of this cluster occurs.
+00092                 */
+00093                 _LastClipWasDistMaxClip= false;
+00094                 _LastClipWasFrustumClip= false;
+00095                 return;
+00096         }
+00097 
+00098         // First, clip DistMax.
+00099         CAABBox         &bbox= cluster->_BBox;
+00100         // if clip DistMax enabled
+00101         if(cluster->_DistMax!=-1)
+00102         {
+00103                 CVector         c= bbox.getCenter();
+00104                 float           dist= (c - clipTrav->CamPos).norm();
+00105                 // it the bbox is entirely out the distMax
+00106                 if( dist-cluster->_Radius > cluster->_DistMax )
+00107                 {
+00108                         // if the cluster was DistMax-visible at last frame
+00109                         if( !_LastClipWasDistMaxClip )
+00110                         {
+00111                                 // Advert sons of the clip. Important for CMeshMultiLodInstace. Do it for me and my sons.
+00112                                 forceClip(IBaseClipObs::DistMaxClip);
+00113                                 // new state.
+00114                                 _LastClipWasDistMaxClip= true;
+00115                         }
+00116                         // quit
+00117                         return;
+00118                 }
+00119                 else
+00120                 {
+00121                         // reset.
+00122                         _LastClipWasDistMaxClip= false;
+00123                 }
+00124         }
+00125 
+00126         // Then clip against pyramid
+00127         bool    unspecified= false;
+00128         bool    visible= true;
+00129         for(sint i=0;i<(sint)clipTrav->WorldPyramid.size();i++)
+00130         {
+00131                 // We are sure that pyramid has normalized plane normals.
+00132                 if(!bbox.clipBack(clipTrav->WorldPyramid[i]))
+00133                 {
+00134                         visible= false;
+00135                         break;
+00136                 }
+00137                 // else test is the bbox is partially or fully in the plane
+00138                 else if(!unspecified)
+00139                 {
+00140                         // if clipFront AND clipBack, it means partially.
+00141                         if(bbox.clipFront(clipTrav->WorldPyramid[i]))
+00142                                 unspecified= true;
+00143                 }
+00144         }
+00145 
+00146         // if ! visible at all, just skip sons.
+00147         if(!visible)
+00148         {
+00149                 // if the cluster was frustum visible at last frame
+00150                 if( !_LastClipWasFrustumClip )
+00151                 {
+00152                         // Advert sons of the clip. Do it for me and my sons.
+00153                         forceClip(IBaseClipObs::FrustumClip);
+00154                         // new state.
+00155                         _LastClipWasFrustumClip= true;
+00156                 }
+00157         }
+00158         else
+00159         {
+00160                 // reset frustum clip cache.
+00161                 _LastClipWasFrustumClip= false;
+00162 
+00163                 // clip sons.
+00164                 if(unspecified)
+00165                 {
+00166                         // clip the sons individually 
+00167                         traverseSons();
+00168                 }
+00169                 else
+00170                 {
+00171                         // udpdate the sons, but don't clip, because we know they are fully visible.
+00172                         clipTrav->ForceNoFrustumClip= true;
+00173                         traverseSons();
+00174                         clipTrav->ForceNoFrustumClip= false;
+00175                 }
+00176         }
+00177 }
+00178 
+00179 
+00180 } // NL3D
+
quad_grid_clip_cluster.cpp
