khanat-code-old/code/nel/src/3d/mrm_level_detail.cpp
2010-05-06 02:08:41 +02:00

53 lines
1.6 KiB
C++

// NeL - MMORPG Framework <http://dev.ryzom.com/projects/nel/>
// Copyright (C) 2010 Winch Gate Property Limited
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU Affero General Public License as
// published by the Free Software Foundation, either version 3 of the
// License, or (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Affero General Public License for more details.
//
// You should have received a copy of the GNU Affero General Public License
// along with this program. If not, see <http://www.gnu.org/licenses/>.
#include "std3d.h"
#include "nel/3d/mrm_level_detail.h"
namespace NL3D
{
// ***************************************************************************
void CMRMLevelDetail::compileDistanceSetup()
{
// Compute _OODistDelta.
OODistanceDelta= 1.0f / (DistanceCoarsest - DistanceFinest);
/* Compute exponent pow, such that 0.5= dMiddle^pow;
ie 0.5= e(ln dMiddle * pow)
*/
float dMiddle= (DistanceCoarsest - DistanceMiddle) * OODistanceDelta;
DistancePow= (float)(log(0.5) / log(dMiddle));
}
// ***************************************************************************
float CMRMLevelDetail::getLevelDetailFromDist(float dist)
{
if(dist <= DistanceFinest)
return 1;
if(dist >= DistanceCoarsest)
return 0;
float d= (DistanceCoarsest - dist) * OODistanceDelta;
return (float)pow(d, DistancePow);
}
} // NL3D