#ifndef ShavePerVertTexInfo_h
#define ShavePerVertTexInfo_h

// Shave and a Haircut
// (c) 2019 Epic Games
// US Patent 6720962

//	This class is used to store a node's per-vertex texture data.
class ShavePerVertTexInfo
{
public:
						ShavePerVertTexInfo();
	virtual				~ShavePerVertTexInfo();

	//	Only a small number of hair parameters are applied per-vertex, as
	//	opposed to per-hair. These next three methods provide a compact
	//	enumeration for these parameters from 0 to numParams()-1

	//	Returns the total number of per-vertex parameters available.
	static unsigned int	numParams()		{ return mNumVertParams; }

	//	Stores in 'paramIdx' the index from 0 to numParams()-1 of the given
	//	parameter number and returns true.
	//	If 'paramNumber' is not a per-vertex parameter
	//	then false is returned and the value of 'paramIdx' is undefined.
	static bool			getParamIdx(int paramNumber, unsigned int& paramIdx);

	//	Returns the parameter number of the i'th per-vertex parameter.
	//	Returns -1 if 'paramIdx' is invalid.
	static int			getParamNumber(unsigned int paramIdx);

	float				getValue(
							unsigned int paramIdx,
							unsigned int vertIdx
						) const;

	//	This must be called before storing any texture values. If there is
	//	existing texture data it will be deleted.
	void				init(unsigned int numVertices);

	static bool			isPerVertParam(int paramNumber);

	bool				setValue(
							unsigned int	paramIdx,
							unsigned int	vertIdx,
							float			value
						);

protected:
	void				clear(bool all);

	bool			mIsInitialized;
	unsigned int	mNumVertices;
	float**			mTextureValues;

	static const int			mVertParams[];
	static const unsigned int	mNumVertParams;
};


inline bool ShavePerVertTexInfo::getParamIdx(
	int paramNumber, unsigned int& paramIdx
)
{
	for (paramIdx = 0; paramIdx < mNumVertParams; ++paramIdx)
		if (mVertParams[paramIdx] == paramNumber) return true;

	paramIdx = 0;

	return false;
}


inline int ShavePerVertTexInfo::getParamNumber(unsigned int paramIdx)
{
	if (paramIdx < mNumVertParams) return mVertParams[paramIdx];

	return -1;
}


inline float ShavePerVertTexInfo::getValue(
	unsigned int paramIdx, unsigned int vertIdx
) const
{
	if ((mTextureValues != 0)
	&&	(paramIdx < mNumVertParams)
	&&	(mTextureValues[paramIdx] != 0)
	&&	(vertIdx < mNumVertices))
	{
		return mTextureValues[paramIdx][vertIdx];
	}

	return 1.0f;
}


inline bool ShavePerVertTexInfo::isPerVertParam(int paramNum)
{
	for (unsigned int i = 0; i < mNumVertParams; ++i)
		if (mVertParams[i] == paramNum) return true;

	return false;
}

#endif