/* -*-c++-*- */
/* osgEarth - Dynamic map generation toolkit for OpenSceneGraph
 * Copyright 2016 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 OSGEARTHFEATURES_SCATTER_FILTER_H
#define OSGEARTHFEATURES_SCATTER_FILTER_H 1

#include <osgEarthFeatures/Common>
#include <osgEarthFeatures/Filter>
#include <osgEarth/Random>

namespace osgEarth { namespace Features
{
    using namespace osgEarth;
    using namespace osgEarth::Symbology;

    /**
     * Feature filter that will take source feature and scatter points within
     * that feature. It will either scatter points randomly (the default), or
     * at fixed intervals, based on the density.
     */
    class OSGEARTHFEATURES_EXPORT ScatterFilter : public FeatureFilter
    {
    public:
        // Call this determine whether this filter is available.
        static bool isSupported() { return true; }

    public:
        ScatterFilter();

        virtual ~ScatterFilter() { }

        /** Approximate instances per sqkm. */
        void setDensity( float value ) { _density = value; }
        float getDensity() const { return _density; }

        /** Whether to randomly scatter (as opposed to a fixed interval scatter) */
        void setRandom( bool value ) { _random = value; }
        bool getRandom() const { return _random; }

        /** Seed value for the random number generator */
        void setRandomSeed( unsigned value ) { _randomSeed = value; }
        unsigned getRandomSeed() const { return _randomSeed; }

    public:
        /** Processes a new feature list */
        virtual FilterContext push( FeatureList& input, FilterContext& context );

    protected:
        void polyScatter(
            const Geometry*         input,
            const SpatialReference* inputSRS,
            const FilterContext&    context, 
            PointSet*               output);

        void lineScatter(
            const Geometry*         input,
            const SpatialReference* inputSRS,
            const FilterContext&    context, 
            PointSet*               output);


    private:
        float    _density;
        bool     _random;
        unsigned _randomSeed;
        Random   _prng;
    };

} } // namespace osgEarth::Features

#endif // OSGEARTHFEATURES_SUBSTITUTE_MODEL_FILTER_H
