/////////////////////////////////////////////////////////////////////////////////
//
//  Copyright (C) Statoil ASA
//  Copyright (C) Ceetron Solutions AS
//
//  ResInsight 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.
//
//  ResInsight 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.
//
/////////////////////////////////////////////////////////////////////////////////

#include "RivTernaryScalarMapper.h"

#include "cvfTextureImage.h"

#include <algorithm>

//--------------------------------------------------------------------------------------------------
///
//--------------------------------------------------------------------------------------------------
RivTernaryScalarMapper::RivTernaryScalarMapper( const cvf::Color3f& undefScalarColor )
    : m_undefScalarColor( undefScalarColor )
    , m_textureSize( 128, 256 )
{
    setTernaryRanges( 0.0, 1.0, 0.0, 1.0 );
}

//--------------------------------------------------------------------------------------------------
///
//--------------------------------------------------------------------------------------------------
cvf::Vec2f RivTernaryScalarMapper::mapToTextureCoord( double soil, double sgas, bool isTransparent ) const
{
    // Clamp the float texture coordinate to avoid edge issues when looking up the texture coordinate
    // The issue was detected on Linux, no similar issues has been seen on Windows
    double edgeClampDelta = 0.001;

    double soilNormalized = ( soil - m_rangeMinSoil ) * m_soilFactor;
    soilNormalized        = std::clamp( soilNormalized, edgeClampDelta, 1.0 - edgeClampDelta );

    double sgasNormalized = ( sgas - m_rangeMinSgas ) * m_sgasFactor;
    sgasNormalized        = std::clamp( sgasNormalized, edgeClampDelta, 1.0 - soilNormalized );
    sgasNormalized /= 2.0;

    if ( isTransparent )
    {
        sgasNormalized += 0.5;
    }

    cvf::Vec2f texCoord( static_cast<float>( soilNormalized ), static_cast<float>( sgasNormalized ) );
    return texCoord;
}

//--------------------------------------------------------------------------------------------------
/// F *
///   * *
///   *   *
///   *     *                Texture in this region is assigned the given opacity level
///   *       *
/// D ***********  E
/// C * SGAS
///   * *
///   *   *                    Texture in this region is opaque
///   *     *
///   *       *
/// A *********** B
/// SWAT          SOIL
//--------------------------------------------------------------------------------------------------
bool RivTernaryScalarMapper::updateTexture( cvf::TextureImage* image, float opacityLevel ) const
{
    CVF_ASSERT( image );
    image->allocate( m_textureSize.x(), m_textureSize.y() );

    image->fill( cvf::Color4ub( cvf::Color3ub( m_undefScalarColor ) ) );

    cvf::uint halfTextureHeight = m_textureSize.y() / 2;

    // Create texture

    float xStride = static_cast<float>( 1.0f / m_textureSize.x() );
    float yStride = static_cast<float>( 1.0f / halfTextureHeight );

    float sgas_red = 0.0f;
    for ( cvf::uint yPos = 0; yPos < halfTextureHeight; yPos++ )
    {
        float soil_green = 0.0f;
        for ( cvf::uint xPos = 0; xPos < m_textureSize.x() - yPos; xPos++ )
        {
            float swat_blue = 1.0f - sgas_red - soil_green;

            cvf::Color3f floatCol( sgas_red, soil_green, swat_blue );

            cvf::ubyte rByteCol = floatCol.rByte();
            cvf::ubyte gByteCol = floatCol.gByte();
            cvf::ubyte bByteCol = floatCol.bByte();

            const cvf::Color4ub clr( rByteCol, gByteCol, bByteCol, 255 );
            image->setPixel( xPos, yPos, clr );

            // Set opacity
            const cvf::Color4ub clrOpacity( rByteCol, gByteCol, bByteCol, static_cast<cvf::ubyte>( 255 * opacityLevel ) );
            image->setPixel( xPos, yPos + halfTextureHeight, clrOpacity );

            soil_green += xStride;
        }
        sgas_red += yStride;
    }

    return true;
}

//--------------------------------------------------------------------------------------------------
///
//--------------------------------------------------------------------------------------------------
void RivTernaryScalarMapper::setTernaryRanges( double soilLower, double soilUpper, double sgasLower, double sgasUpper )
{
    m_rangeMinSoil = soilLower;
    m_rangeMaxSoil = soilUpper;
    m_soilFactor   = 1.0 / ( soilUpper - soilLower );

    m_rangeMinSgas = sgasLower;
    m_rangeMaxSgas = sgasUpper;
    m_sgasFactor   = 1.0 / ( sgasUpper - sgasLower );
}