/* osgEarth
* Copyright 2008-2012 Pelican Mapping
* MIT License
*/
#pragma once

#include <osgEarth/VisibleLayer>
#include <osgEarth/Color>
#include <osg/Texture2D>
#include <osg/TransferFunction>

namespace osgEarth
{
    /**
     * Layer that renders a color ramp based on Elevation data in the Map.
     */
    class OSGEARTH_EXPORT ContourMapLayer : public VisibleLayer
    {
    public:
        class OSGEARTH_EXPORT Options : public VisibleLayer::Options {
        public:
            META_LayerOptions(osgEarth, Options, VisibleLayer::Options);
            struct Stop {
                float elevation;
                Color color;
            };
            OE_OPTION_VECTOR(Stop, stops);
            OE_OPTION(std::string, vdatum, "egm96");
            virtual Config getConfig() const;
            static Config getMetadata();
        private:
            void fromConfig(const Config& conf);
        };

    public:
        META_Layer(osgEarth, ContourMapLayer, Options, VisibleLayer, ContourMap);

        //! Sets a transfer function that maps elevations to colors.
        //! To change the color ramp at runtime, it is not sufficient to simply
        //! edit the transfer function - you must call dirty() or setTransferFunction()
        //! on this layer to apply properly.
        void setTransferFunction(osg::TransferFunction1D* xf);

        //! Gets the transfer function
        osg::TransferFunction1D* getTransferFunction() const { return _xfer.get(); }

        //! Re-applies the transfer function after editing it
        void dirty();

    public: // Layer

        //! Called by constructors
        void init() override;

        //! MapNode will call this function when terrain resources are available
        void prepareForRendering(TerrainEngine*) override;

        //! Release resources on close
        Status closeImplementation() override;

    protected:

        //! Destructor
        virtual ~ContourMapLayer() { }

        typedef osg::Texture2D TextureType;

        TextureImageUnitReservation _reservationColorRamp;
        TextureImageUnitReservation _reservationGeoid;
        osg::ref_ptr<osg::TransferFunction1D> _xfer;
        osg::ref_ptr<TextureType> _xferTexture;
        osg::ref_ptr<osg::Uniform> _xferSampler;
        osg::ref_ptr<osg::Uniform> _xferMin;
        osg::ref_ptr<osg::Uniform> _xferRange;
    };

}
OSGEARTH_SPECIALIZE_CONFIG(osgEarth::ContourMapLayer::Options);
