/* -*-c++-*- */
/* osgEarth - Dynamic map generation toolkit for OpenSceneGraph
 * Copyright 2015 Pelican Mapping
 * http://osgearth.org
 *
 * osgEarth 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 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 Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>
 */
#ifndef OSGEARTHUTIL_CHROMAKEY_COLOR_FILTER
#define OSGEARTHUTIL_CHROMAKEY_COLOR_FILTER

#include <osgEarthUtil/Common>
#include <osgEarth/ColorFilter>
#include <osg/Uniform>

namespace osgEarth { namespace Util
{
    using namespace osgEarth;

    /**
    * Color filter that makes a color transparent.
    */
    class OSGEARTHUTIL_EXPORT ChromaKeyColorFilter : public osgEarth::ColorFilter
    {
    public:
        ChromaKeyColorFilter(void);
        ChromaKeyColorFilter(const Config& conf);
        virtual ~ChromaKeyColorFilter(void) { }

        /**
         * The color to make transparent, each component is [0..1]
         */
        void setColor( const osg::Vec3f& color );
        osg::Vec3f getColor() const;

        /**
         * The linear distance to search for "similar" colors to make transparent.
         * Currently this is doing a simple 3D distance comparison to find similar colors.
         */
        void setDistance( float distance );
        float getDistance() const;

    public: // ColorFilter
        virtual std::string getEntryPointFunctionName(void) const;
        virtual void install(osg::StateSet* stateSet) const;
        virtual Config getConfig() const;

    protected:
        unsigned int _instanceId;
        osg::ref_ptr<osg::Uniform> _color;
        osg::ref_ptr<osg::Uniform> _distance;

        void init();
    };

} } // namespace osgEarth::Util

#endif // OSGEARTHUTIL_CHROMAKEY_COLOR_FILTER
