//##################################################################################################
//
//   Custom Visualization Core library
//   Copyright (C) 2011-2013 Ceetron AS
//
//   This library may be used under the terms of either the GNU General Public License or
//   the GNU Lesser General Public License as follows:
//
//   GNU General Public License Usage
//   This library is free software: you can redistribute it and/or modify
//   it under the terms of the GNU General Public License as published by
//   the Free Software Foundation, either version 3 of the License, or
//   (at your option) any later version.
//
//   This library 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 General Public License at <<http://www.gnu.org/licenses/gpl.html>>
//   for more details.
//
//   GNU Lesser General Public License Usage
//   This library is free software; you can redistribute it and/or modify
//   it under the terms of the GNU Lesser General Public License as published by
//   the Free Software Foundation; either version 2.1 of the License, or
//   (at your option) any later version.
//
//   This library 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 Lesser General Public License at <<http://www.gnu.org/licenses/lgpl-2.1.html>>
//   for more details.
//
//##################################################################################################


#include "cvfScalarMapperDiscreteLinear.h"
#include "cvfMath.h"
#include "cvfTextureImage.h"

#include <cmath>
#include <assert.h>

namespace cvf {
//==================================================================================================
///
/// \class cvf::ScalarMapperDiscreteLinear
/// \ingroup Render
///
/// Maps scalar values to texture coordinates/colors using discrete linear mapping
//==================================================================================================

ScalarMapperDiscreteLinear::ScalarMapperDiscreteLinear()
{
 
}

//--------------------------------------------------------------------------------------------------
/// 
//--------------------------------------------------------------------------------------------------
Color3ub ScalarMapperDiscreteLinear::mapToColor(double scalarValue) const
{
    assert(m_sortedLevels.size() > 0);

    double discVal = ScalarMapperDiscreteLinear::discretizeToLevelBelow(scalarValue, m_sortedLevels);
    std::set<double>::reverse_iterator it = m_sortedLevels.rbegin();
    
    if (m_sortedLevels.size() > 1 ) it++;
    
    double levelUnderMax = *it;
    double normDiscVal = normalizedValue(discVal);
    double normSemiMaxVal = normalizedValue(levelUnderMax);
    double adjustedNormVal = 0;
    if (normSemiMaxVal != 0) adjustedNormVal = cvf::Math::clamp(normDiscVal/normSemiMaxVal, 0.0, 1.0);

    return colorFromUserColorGradient(adjustedNormVal);
}

//--------------------------------------------------------------------------------------------------
/// 
//--------------------------------------------------------------------------------------------------
double ScalarMapperDiscreteLinear::discretizeToLevelBelow(double scalarValue, const std::set<double>& sortedLevels) 
{
    std::set<double>::iterator it;

    it = sortedLevels.upper_bound(scalarValue);
    if (it == sortedLevels.begin()) return (*it);
    if (it == sortedLevels.end()) return (*sortedLevels.rbegin());
    it--;
    double lowerValue = *it;

    return lowerValue;
}

//--------------------------------------------------------------------------------------------------
/// 
//--------------------------------------------------------------------------------------------------
double ScalarMapperDiscreteLinear::normalizedValue(double domainScalarValue) const
{
    double range = m_rangeMax - m_rangeMin;
    if (range != 0) return cvf::Math::clamp((domainScalarValue - m_rangeMin)/range, 0.0, 1.0);
    else            return 0;
} 

//--------------------------------------------------------------------------------------------------
/// 
//--------------------------------------------------------------------------------------------------
double ScalarMapperDiscreteLinear::domainValue(double normalizedPosition) const
{
    double range = m_rangeMax - m_rangeMin;

    return (normalizedPosition * range + m_rangeMin);

}

} // namespace cvf