discrete_poisson_disk_pattern.h

// Description: Discrete poisson-disk pattern
// Detail: Sets those pixels for which the poisson-disk condition is fulfilled

#ifndef PASTELGFX_DISCRETE_POISSON_DISK_PATTERN_H
#define PASTELGFX_DISCRETE_POISSON_DISK_PATTERN_H

#include "pastel/sys/view/view.h"
#include "pastel/sys/view/view_visit.h"
#include "pastel/sys/array.h"

#include "pastel/gfx/drawing.h"

namespace Pastel
{

    namespace DiscretePoissonDiskPattern_
    {

        class Mixer
        {
        public:
            bool operator()(bool image,  bool texture) const
            {
                return (image && !texture);
            }
        };

        template <integer N, typename Image_View, typename Element_ConstView>
        class Visitor
        {
        public:
            Visitor(
                const ConstView<N, bool, Element_ConstView>& element,
                const View<N, bool, Image_View>& image)
                : element_(element)
                , image_(image)
                , elementOffset_(element.extent() / 2)
            {
            }

            void operator()(
                const Vector<integer, N>& position,
                bool& image) const
            {
                Mixer mixer;
                if (image)
                {
                    drawView(
                        element_,
                        position - elementOffset_,
                        image_,
                        mixer);

                    image = true;
                }
            }

        private:
            const ConstView<N, bool, Element_ConstView>& element_;
            const View<N, bool, Image_View>& image_;
            Vector<integer, N> elementOffset_;
        };

    }

    template <integer N, typename Image_View, typename Element_ConstView>
    void discretePoissonDiskPattern(
        const ConstView<N, bool, Element_ConstView>& element,
        const View<N, bool, Image_View>& image)
    {
        DiscretePoissonDiskPattern_::Visitor<N, Image_View, Element_ConstView>
            visitor(element, image);

        visitPosition(image, visitor);
    }

}

#endif