MaterialDensityPair.h

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#ifndef __PolyVox_MaterialDensityPair_H__
#define __PolyVox_MaterialDensityPair_H__

#include "PolyVoxCore/DefaultIsQuadNeeded.h" //we'll specialise this function for this voxel type
#include "PolyVoxCore/DefaultMarchingCubesController.h" //We'll specialise the controller contained in here

#include "Impl/TypeDef.h"

namespace PolyVox
{
    template <typename Type, uint8_t NoOfMaterialBits, uint8_t NoOfDensityBits>
    class MaterialDensityPair
    {
    public:
        MaterialDensityPair() : m_uMaterial(0), m_uDensity(0) {}
        MaterialDensityPair(Type uMaterial, Type uDensity) : m_uMaterial(uMaterial), m_uDensity(uDensity) {}

        bool operator==(const MaterialDensityPair& rhs) const
        {
            return (m_uMaterial == rhs.m_uMaterial) && (m_uDensity == rhs.m_uDensity);
        };

        bool operator!=(const MaterialDensityPair& rhs) const
        {
            return !(*this == rhs);
        }

        MaterialDensityPair<Type, NoOfMaterialBits, NoOfDensityBits>& operator+=(const MaterialDensityPair<Type, NoOfMaterialBits, NoOfDensityBits>& rhs)
        {
            m_uDensity += rhs.m_uDensity;

            // What should we do with the material? Conceptually the idea of adding materials makes no sense, but for our
            // purposes we consider the 'sum' of two materials to just be the max. At least this way it is commutative.
            m_uMaterial = (std::max)(m_uMaterial, rhs.m_uMaterial);

            return *this;
        }

        MaterialDensityPair<Type, NoOfMaterialBits, NoOfDensityBits>& operator/=(uint32_t rhs)
        {
            // There's nothing sensible we can do with the material, so this function only affects the density.
            m_uDensity /= rhs;
            return *this;
        }

        Type getDensity() const { return m_uDensity; }
        Type getMaterial() const { return m_uMaterial; }

        void setDensity(Type uDensity) { m_uDensity = uDensity; }
        void setMaterial(Type uMaterial) { m_uMaterial = uMaterial; }

        static Type getMaxDensity() { return (0x01 << NoOfDensityBits) - 1; }
        static Type getMinDensity() { return 0; }

    private:
        Type m_uMaterial : NoOfMaterialBits;
        Type m_uDensity : NoOfDensityBits;
    };

    template<typename Type, uint8_t NoOfMaterialBits, uint8_t NoOfDensityBits>
    class DefaultIsQuadNeeded< MaterialDensityPair<Type, NoOfMaterialBits, NoOfDensityBits> >
    {
    public:
        bool operator()(MaterialDensityPair<Type, NoOfMaterialBits, NoOfDensityBits> back, MaterialDensityPair<Type, NoOfMaterialBits, NoOfDensityBits> front, uint32_t& materialToUse)
        {
            if((back.getMaterial() > 0) && (front.getMaterial() == 0))
            {
                materialToUse = static_cast<uint32_t>(back.getMaterial());
                return true;
            }
            else
            {
                return false;
            }
        }
    };

    template <typename Type, uint8_t NoOfMaterialBits, uint8_t NoOfDensityBits>
    class DefaultMarchingCubesController< MaterialDensityPair<Type, NoOfMaterialBits, NoOfDensityBits> >
    {
    public:
        typedef Type DensityType;
        typedef Type MaterialType;

        DefaultMarchingCubesController(void)
        {
            // Default to a threshold value halfway between the min and max possible values.
            m_tThreshold = (MaterialDensityPair<Type, NoOfMaterialBits, NoOfDensityBits>::getMinDensity() + MaterialDensityPair<Type, NoOfMaterialBits, NoOfDensityBits>::getMaxDensity()) / 2;
        }

        DefaultMarchingCubesController(DensityType tThreshold)
        {
            m_tThreshold = tThreshold;
        }

        DensityType convertToDensity(MaterialDensityPair<Type, NoOfMaterialBits, NoOfDensityBits> voxel)
        {
            return voxel.getDensity();
        }

        MaterialType convertToMaterial(MaterialDensityPair<Type, NoOfMaterialBits, NoOfDensityBits> voxel)
        {
            return voxel.getMaterial();
        }

        DensityType getThreshold(void)
        {           
            return m_tThreshold;
        }       

    private:
        DensityType m_tThreshold;
    };

    typedef MaterialDensityPair<uint8_t, 4, 4> MaterialDensityPair44;
    typedef MaterialDensityPair<uint16_t, 8, 8> MaterialDensityPair88;
}

#endif