/////////////////////////////////////////////////////////////////////////////////
//
//  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 "RivTernaryScalarMapperEffectGenerator.h"

#include "RiaColorTables.h"

#include "RivTernaryScalarMapper.h"

#include "cvfRenderStateBlending.h"
#include "cvfRenderStateCullFace.h"
#include "cvfRenderStateDepth.h"
#include "cvfRenderStateTextureBindings.h"
#include "cvfRenderState_FF.h"
#include "cvfSampler.h"
#include "cvfShaderProgram.h"
#include "cvfShaderProgramGenerator.h"
#include "cvfShaderSourceProvider.h"
#include "cvfTexture.h"
#include "cvfTexture2D_FF.h"
#include "cvfUniform.h"

#include <algorithm>

//==================================================================================================
//
// RivTernaryScalarMapperEffectGenerator
//
//==================================================================================================

//--------------------------------------------------------------------------------------------------
///
//--------------------------------------------------------------------------------------------------
RivTernaryScalarMapperEffectGenerator::RivTernaryScalarMapperEffectGenerator( const RivTernaryScalarMapper* scalarMapper,
                                                                              caf::PolygonOffset            polygonOffset )
    : m_undefinedColor( RiaColorTables::undefinedCellColor() )
{
    m_scalarMapper     = scalarMapper;
    m_polygonOffset    = polygonOffset;
    m_opacityLevel     = 1.0f;
    m_faceCulling      = caf::FC_NONE;
    m_enableDepthWrite = true;
    m_disableLighting  = false;
}

//--------------------------------------------------------------------------------------------------
///
//--------------------------------------------------------------------------------------------------
void RivTernaryScalarMapperEffectGenerator::setOpacityLevel( float opacity )
{
    m_opacityLevel = std::clamp( opacity, 0.0f, 1.0f );
}

//--------------------------------------------------------------------------------------------------
///
//--------------------------------------------------------------------------------------------------
void RivTernaryScalarMapperEffectGenerator::setUndefinedColor( cvf::Color3f color )
{
    m_undefinedColor = color;
}

//--------------------------------------------------------------------------------------------------
///
//--------------------------------------------------------------------------------------------------
void RivTernaryScalarMapperEffectGenerator::setFaceCulling( caf::FaceCulling faceCulling )
{
    m_faceCulling = faceCulling;
}

//--------------------------------------------------------------------------------------------------
///
//--------------------------------------------------------------------------------------------------
void RivTernaryScalarMapperEffectGenerator::enableDepthWrite( bool enableWrite )
{
    m_enableDepthWrite = enableWrite;
}

//--------------------------------------------------------------------------------------------------
///
//--------------------------------------------------------------------------------------------------
void RivTernaryScalarMapperEffectGenerator::disableLighting( bool disable )
{
    m_disableLighting = disable;
}

//--------------------------------------------------------------------------------------------------
///
//--------------------------------------------------------------------------------------------------
void RivTernaryScalarMapperEffectGenerator::updateForShaderBasedRendering( cvf::Effect* effect ) const
{
    cvf::ref<cvf::Effect> eff = effect;

    cvf::ShaderProgramGenerator gen( "ScalarMapperMeshEffectGenerator", cvf::ShaderSourceProvider::instance() );
    gen.addVertexCode( cvf::ShaderSourceRepository::vs_Standard );
    gen.addFragmentCode( cvf::ShaderSourceRepository::src_Texture );

    if ( m_disableLighting )
    {
        gen.addFragmentCode( cvf::ShaderSourceRepository::fs_Unlit );
    }
    else
    {
        gen.addFragmentCode( caf::CommonShaderSources::light_AmbientDiffuse() );
        gen.addFragmentCode( cvf::ShaderSourceRepository::fs_Standard );
    }

    cvf::ref<cvf::ShaderProgram> prog = gen.generate();
    eff->setShaderProgram( prog.p() );

    if ( !m_disableLighting ) prog->setDefaultUniform( new cvf::UniformFloat( "u_ecLightPosition", cvf::Vec3f( 0.5, 5.0, 7.0 ) ) );

    // Result mapping texture

    m_textureImage = new cvf::TextureImage();
    m_scalarMapper->updateTexture( m_textureImage.p(), m_opacityLevel );

    cvf::ref<cvf::Texture> texture = new cvf::Texture( m_textureImage.p() );
    cvf::ref<cvf::Sampler> sampler = new cvf::Sampler;
    sampler->setWrapMode( cvf::Sampler::CLAMP_TO_EDGE );
    sampler->setMinFilter( cvf::Sampler::NEAREST );
    sampler->setMagFilter( cvf::Sampler::NEAREST );

    cvf::ref<cvf::RenderStateTextureBindings> texBind = new cvf::RenderStateTextureBindings;
    texBind->addBinding( texture.p(), sampler.p(), "u_texture2D" );
    eff->setRenderState( texBind.p() );

    // Hardware independent:

    updateCommonEffect( eff.p() );
}

//--------------------------------------------------------------------------------------------------
///
//--------------------------------------------------------------------------------------------------
void RivTernaryScalarMapperEffectGenerator::updateForFixedFunctionRendering( cvf::Effect* effect ) const
{
    cvf::ref<cvf::Effect> eff = effect;

    cvf::ref<cvf::RenderStateMaterial_FF> mat = new cvf::RenderStateMaterial_FF( cvf::Color3::WHITE );
    eff->setRenderState( mat.p() );

    cvf::ref<cvf::RenderStateLighting_FF> lighting = new cvf::RenderStateLighting_FF;
    lighting->enableTwoSided( true );
    lighting->enable( !m_disableLighting );
    eff->setRenderState( lighting.p() );

    // Result mapping texture

    m_textureImage = new cvf::TextureImage;
    m_scalarMapper->updateTexture( m_textureImage.p(), m_opacityLevel );

    cvf::ref<cvf::Texture2D_FF> texture = new cvf::Texture2D_FF( m_textureImage.p() );
    texture->setWrapMode( cvf::Texture2D_FF::CLAMP );
    texture->setMinFilter( cvf::Texture2D_FF::NEAREST );
    texture->setMagFilter( cvf::Texture2D_FF::NEAREST );
    cvf::ref<cvf::RenderStateTextureMapping_FF> texMapping = new cvf::RenderStateTextureMapping_FF( texture.p() );
    eff->setRenderState( texMapping.p() );

    // Hardware independent:

    updateCommonEffect( eff.p() );
}

//--------------------------------------------------------------------------------------------------
/// It also modifies the texture, and adds two more pixel lines
/// one with a transparent version of the legend color, and one with color for undefined values
//--------------------------------------------------------------------------------------------------
void RivTernaryScalarMapperEffectGenerator::updateCommonEffect( cvf::Effect* effect ) const
{
    CVF_ASSERT( effect );

    if ( m_polygonOffset != caf::PO_NONE )
    {
        cvf::ref<cvf::RenderStatePolygonOffset> polyOffset = EffectGenerator::createAndConfigurePolygonOffsetRenderState( m_polygonOffset );
        effect->setRenderState( polyOffset.p() );
    }

    // Simple transparency
    if ( m_opacityLevel < 1.0f )
    {
        cvf::ref<cvf::RenderStateBlending> blender = new cvf::RenderStateBlending;
        blender->configureTransparencyBlending();
        effect->setRenderState( blender.p() );
    }

    // Backface culling
    if ( m_faceCulling != caf::FC_NONE )
    {
        cvf::ref<cvf::RenderStateCullFace> faceCulling = new cvf::RenderStateCullFace;
        if ( m_faceCulling == caf::FC_BACK )
        {
            faceCulling->setMode( cvf::RenderStateCullFace::BACK );
        }
        else if ( m_faceCulling == caf::FC_FRONT )
        {
            faceCulling->setMode( cvf::RenderStateCullFace::FRONT );
        }
        else if ( m_faceCulling == caf::FC_FRONT_AND_BACK )
        {
            faceCulling->setMode( cvf::RenderStateCullFace::FRONT_AND_BACK );
        }

        effect->setRenderState( faceCulling.p() );
    }

    if ( !m_enableDepthWrite )
    {
        cvf::ref<cvf::RenderStateDepth> depth = new cvf::RenderStateDepth;
        depth->enableDepthWrite( false );
        effect->setRenderState( depth.p() );
    }
}

//--------------------------------------------------------------------------------------------------
///
//--------------------------------------------------------------------------------------------------
bool RivTernaryScalarMapperEffectGenerator::isEqual( const EffectGenerator* other ) const
{
    const RivTernaryScalarMapperEffectGenerator* otherTextureResultEffect = dynamic_cast<const RivTernaryScalarMapperEffectGenerator*>( other );

    if ( otherTextureResultEffect )
    {
        if ( m_scalarMapper.p() == otherTextureResultEffect->m_scalarMapper && m_polygonOffset == otherTextureResultEffect->m_polygonOffset &&
             m_opacityLevel == otherTextureResultEffect->m_opacityLevel && m_undefinedColor == otherTextureResultEffect->m_undefinedColor &&
             m_faceCulling == otherTextureResultEffect->m_faceCulling && m_enableDepthWrite == otherTextureResultEffect->m_enableDepthWrite &&
             m_disableLighting == otherTextureResultEffect->m_disableLighting )
        {
            cvf::ref<cvf::TextureImage> texImg2 = new cvf::TextureImage;
            otherTextureResultEffect->m_scalarMapper->updateTexture( texImg2.p(), m_opacityLevel );

            return RivTernaryScalarMapperEffectGenerator::isImagesEqual( m_textureImage.p(), texImg2.p() );
        }
    }

    return false;
}

//--------------------------------------------------------------------------------------------------
///
//--------------------------------------------------------------------------------------------------
caf::EffectGenerator* RivTernaryScalarMapperEffectGenerator::copy() const
{
    RivTernaryScalarMapperEffectGenerator* scEffGen = new RivTernaryScalarMapperEffectGenerator( m_scalarMapper.p(), m_polygonOffset );
    scEffGen->m_textureImage                        = m_textureImage;
    scEffGen->m_opacityLevel                        = m_opacityLevel;
    scEffGen->m_undefinedColor                      = m_undefinedColor;
    scEffGen->m_faceCulling                         = m_faceCulling;
    scEffGen->m_enableDepthWrite                    = m_enableDepthWrite;
    scEffGen->m_disableLighting                     = m_disableLighting;

    return scEffGen;
}

//--------------------------------------------------------------------------------------------------
/// Tests whether two texture images are equal. It might in some rare cases not detect the difference
/// but to make the comparison fast only some sampling points are used. If both pointers are nullptr,
/// they are considered equal.
//--------------------------------------------------------------------------------------------------
bool RivTernaryScalarMapperEffectGenerator::isImagesEqual( const cvf::TextureImage* texImg1, const cvf::TextureImage* texImg2 )
{
    if ( texImg1 == nullptr && texImg2 == nullptr ) return true;

    if ( texImg1 != nullptr && texImg2 != nullptr && texImg1->height() == texImg2->height() && texImg1->width() == texImg2->width() &&
         texImg1->width() > 0 && texImg1->height() > 0 && texImg1->pixel( 0, 0 ) == texImg2->pixel( 0, 0 ) &&
         texImg1->pixel( texImg1->width() - 1, texImg1->height() - 1 ) == texImg2->pixel( texImg1->width() - 1, texImg1->height() - 1 ) &&
         texImg1->pixel( texImg1->width() / 2, texImg1->height() / 2 ) == texImg2->pixel( texImg1->width() / 2, texImg1->height() / 2 ) &&
         texImg1->pixel( texImg1->width() / 4, texImg1->height() / 4 ) == texImg2->pixel( texImg1->width() / 4, texImg1->height() / 4 ) &&
         texImg1->pixel( texImg1->width() / 2 + texImg1->width() / 4, texImg1->height() / 2 + texImg1->height() / 4 ) ==
             texImg2->pixel( texImg1->width() / 2 + texImg1->width() / 4, texImg1->height() / 2 + texImg1->height() / 4 ) )
    {
        return true;
    }

    return false;
}