source: Revenant/geoworld/include/gwmorphs/winderode.h

#pragma once

#include "geomorph.h"
#include "gwutil.h"
#include "gmregistry.h"
#include "gwtypes.h"

namespace geoworld
{
        class WindErosionGM : public HeightMapGeoMorph
        {
        private:
                typedef float RationalType;

                unsigned int _iterations;
                RationalType _frDecayLevel;
                bool _bSmoothPost;

                const IGeoWorldAccessor * _pAccessor;
                const GMScalarField * _psfDensity;

                RationalType _fgaussblur[5][5];

                using NoiseGen = NoiseGenerator< RationalType >;
                NoiseGen _ngen;

                template< typename T >
                inline void grad5( const mars::ScalarField< T > & hmf, const signed int x, const signed int y, VectorTag< RationalType >:: V2 & v ) const
                {
                        v.x = (hmf(x + 2, y) - hmf(x - 2, y)) / static_cast< T > (4);
                        v.y = (hmf(x, y + 2) - hmf(x, y - 2)) / static_cast< T > (4);
                }

                inline RationalType & gaussblur (const signed int x, const signed int y)
                {
                        assert(x >= -2 && y >= -2 && x <= +2 && y <= +2);
                        return _fgaussblur[x + 2][y + 2];
                }
                inline RationalType gaussblur (const signed int x, const signed int y) const
                {
                        assert(x >= -2 && y >= -2 && x <= +2 && y <= +2);
                        return _fgaussblur[x + 2][y + 2];
                }

        public:
                WindErosionGM (
                        const unsigned int nIterations = 8,
                        const float frDecayLevel = 0.1f,
                        const bool bSmoothPost = true
                );
                ~WindErosionGM();

                void init (SynthesisSession & manager, const IGeoWorldAccessor & accessor, const unsigned short nMaxWidth, const unsigned short nMaxHeight);
                void doMorph (LockedGWSection & section) const;
        };

        class WindErosionGTFactory : public GeoTemplateFactory, public IOpenGeoMorphFactory
        {
        private:
                mars::RangeX< unsigned int > _mmnIterations;
                float _frDecayLevel;
                bool _bSmoothPost;

        public:
                virtual GeoMorph * createRandomInstance() const;
                virtual void configure( IConfigGTFactory * pFactoryConfig, const IConfigGTFactory::Settings & settings );
        };
}