/* -*-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 OSGEARTH_ELEVATION_FIELD_H
#define OSGEARTH_ELEVATION_FIELD_H 1

#include <osgEarth/Common>
#include <osgEarth/GeoCommon>
#include <osg/Object>
#include <osg/Vec3f>

namespace osgEarth
{
    /**
     * A grid of elevation data.
     */
    class OSGEARTH_EXPORT ElevationField : public osg::Object
    {
    public:
        META_Object(osgEarth, ElevationField);

        /** Constructor */
        ElevationField();

        /**
         * Sets the width and height (in samples) of the field.
         * This will wipe out any existing data.
         */
        void setSize(unsigned width, unsigned height);

        /**
         * Gets the height value at sample x,y.
         */
        float getHeight(unsigned x, unsigned y) const;

        /**
         * If the data is "dirty", recalculate derived values like
         * slope, curvature, min and max.
         */
        void update(float spacing);


    protected:
        unsigned                _width, _height;
        std::vector<float>      _heights;
        std::vector<float>      _slopes;
        std::vector<float>      _curvatures;
        std::vector<float>      _aspects;
        std::vector<osg::Vec3f> _normals;
        float                   _min, _max;
        bool                    _dirty;
        float                   _spacing;

    protected:
        virtual ~ElevationField() { }

        // Copy CTOR hidden for now
        ElevationField(const ElevationField& rhs, const osg::CopyOp& copy) { }

        void computeSlopeAndCurvature();
    };
}

#endif // OSGEARTH_ELEVATION_FIELD_H