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00001 
+00007 /* Copyright, 2000-2002 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 #ifndef NL_MRM_LEVEL_DETAIL_H
+00027 #define NL_MRM_LEVEL_DETAIL_H
+00028 
+00029 #include "nel/misc/types_nl.h"
+00030 #include "nel/misc/common.h"
+00031 
+00032 
+00033 namespace NL3D 
+00034 {
+00035 
+00036 
+00037 // ***************************************************************************
+00038 /* This is used to have correct max Polygon count setuped. This suppose that MRM.NumLod==10
+00039         Hence, a mean value of 0.5*1/10 is used
+00040 */
+00041 #define NL3D_MRM_LD_SHIFT_POLY_COUNT    0.05f
+00042 
+00043 
+00044 // ***************************************************************************
+00051 class CMRMLevelDetail
+00052 {
+00053 public:
+00054 
+00056         uint32                          MinFaceUsed;
+00058         uint32                          MaxFaceUsed;
+00059 
+00061         float                           DistanceFinest;
+00063         float                           DistanceMiddle;
+00065         float                           DistanceCoarsest;
+00066 
+00068         float                           OODistanceDelta;
+00069         float                           DistancePow;
+00070 
+00071 public:
+00073         CMRMLevelDetail() {}
+00074 
+00076         void                            compileDistanceSetup();
+00077 
+00079         float                           getLevelDetailFromDist(float dist);
+00080 
+00082         float                           getNumTriangles (float dist)
+00083         {
+00084                 // return the lod detail [0,1].
+00085                 float   ld= getLevelDetailFromDist(dist);
+00086                 // return in nb face.
+00087                 if(ld<=0)
+00088                         return (float)MinFaceUsed;
+00089                 else
+00090                 {
+00091                         /* over-estimate the number of poly rendered 
+00092                                 because this is always the higher Lod which is rendered, geomorphing to the coarser one.
+00093                                 NB: still need to over-estimate if ld==1, because getLevelDetailFromPolyCount() remove the shift...
+00094                         */
+00095                         ld+= NL3D_MRM_LD_SHIFT_POLY_COUNT;
+00096                         return MinFaceUsed + ld * (MaxFaceUsed - MinFaceUsed);
+00097                 }
+00098         }
+00099 
+00101         float                           getLevelDetailFromPolyCount(float polygonCount)
+00102         {
+00103                 float   ld;
+00104                 if(MaxFaceUsed > MinFaceUsed)
+00105                 {
+00106                         // compute the level of detail we want.
+00107                         ld= (polygonCount - MinFaceUsed) / (MaxFaceUsed - MinFaceUsed);
+00108                         /* remove the value added in getNumTriangles(). For the same reason:
+00109                                 this is always the higher Lod which is rendered, geomorphing to the coarser one.
+00110                                 Hence we must degrade a bit.
+00111                                 NB: if polygonCount==MinFaceUsed, then we have here ld= -NL3D_MRM_LD_SHIFT_POLY_COUNT (ie -0.05f)
+00112                                 but it is clamped below
+00113                         */
+00114                         ld-= NL3D_MRM_LD_SHIFT_POLY_COUNT;
+00115                         NLMISC::clamp(ld, 0, 1);
+00116                 }
+00117                 else
+00118                         ld= 1;
+00119 
+00120                 return ld;
+00121         }
+00122 
+00123 };
+00124 
+00125 
+00126 } // NL3D
+00127 
+00128 
+00129 #endif // NL_MRM_LEVEL_DETAIL_H
+00130 
+00131 /* End of mrm_level_detail.h */
+