polyvox/include/PolyVox/MaterialDensityPair.h

/*******************************************************************************
Copyright (c) 2005-2009 David Williams

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Permission is granted to anyone to use this software for any purpose,
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    claim that you wrote the original software. If you use this software
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    appreciated but is not required.

    2. Altered source versions must be plainly marked as such, and must not be
    misrepresented as being the original software.

    3. This notice may not be removed or altered from any source
    distribution. 	
*******************************************************************************/

#ifndef __PolyVox_MaterialDensityPair_H__
#define __PolyVox_MaterialDensityPair_H__

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

#include "Impl/PlatformDefinitions.h"

namespace PolyVox
{
	/// This class represents a voxel storing only a density.
	////////////////////////////////////////////////////////////////////////////////
	/// Detailed description...
	///
	/// \sa Density, Material
	////////////////////////////////////////////////////////////////////////////////
	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, MaterialDensityPair<Type, NoOfMaterialBits, NoOfDensityBits>& materialToUse)
		{
			if((back.getMaterial() > 0) && (front.getMaterial() == 0))
			{
				materialToUse = back;
				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();
		}

		MaterialDensityPair<Type, NoOfMaterialBits, NoOfDensityBits> blendMaterials(MaterialDensityPair<Type, NoOfMaterialBits, NoOfDensityBits> a, MaterialDensityPair<Type, NoOfMaterialBits, NoOfDensityBits> b, float /*weight*/)
		{
			if(convertToDensity(a) > convertToDensity(b))
			{
				return a;
			}
			else
			{
				return b;
			}
		}

		DensityType getThreshold(void)
		{			
			return m_tThreshold;
		}

		void setThreshold(DensityType tThreshold)
		{
			m_tThreshold = tThreshold;
		}

	private:
		DensityType m_tThreshold;
	};

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

#endif