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#ifndef __CGLA_TABLETRIGONOMETRY_H__
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#define __CGLA_TABLETRIGONOMETRY_H__
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#include <vector>
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#include "CGLA.h"
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namespace CGLA {
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	namespace TableTrigonometry
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	{
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		typedef unsigned short int Angle;
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		const Angle  ANGLE_MAX = USHRT_MAX>>2;
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		const float ANGLE_FACTOR = float(ANGLE_MAX) / M_PI_2;
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		class CosTable
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		{
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			std::vector<float> tab;
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		public:
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			CosTable(): tab(ANGLE_MAX+1)
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			{
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				for(int i=0;i<ANGLE_MAX+1; i++)
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					tab[i] = cos(i/ANGLE_FACTOR);
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			}
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			float operator[](int i) const {return tab[i];}
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		};
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		const CosTable& COS_TABLE();
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		inline float angle2float(Angle theta)
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		{
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			static float MPI2 = (float)(M_PI * 2);
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			switch(theta & 3)
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				{
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				case 0: return   (theta>>2)/ANGLE_FACTOR;
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				case 1: return M_PI - (theta>>2)/ANGLE_FACTOR;
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				case 2: return M_PI + (theta>>2)/ANGLE_FACTOR;
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				case 3: return MPI2 - (theta>>2)/ANGLE_FACTOR;
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				}
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			return 0;
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		}
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		inline float t_cos(Angle theta)
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		{
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			switch(theta & 3)
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				{
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				case 0: return   COS_TABLE()[ theta>>2 ];
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				case 1: return - COS_TABLE()[ theta>>2 ];
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				case 2: return - COS_TABLE()[ theta>>2 ];
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				case 3: return   COS_TABLE()[ theta>>2 ];
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				}
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			return 0;
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		}
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		inline float t_sin(Angle theta)
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		{
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			switch(theta & 3)
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				{
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				case 0: return   COS_TABLE()[ ANGLE_MAX - (theta>>2) ];
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				case 1: return   COS_TABLE()[ ANGLE_MAX - (theta>>2) ];
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				case 2: return - COS_TABLE()[ ANGLE_MAX - (theta>>2) ];
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				case 3: return - COS_TABLE()[ ANGLE_MAX - (theta>>2) ];
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				}
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			return 0;
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		}
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		inline Angle t_atan(float x, float y)
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		{
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			Angle theta = Angle( acos(fabs(x)/sqrt(x*x+y*y)) * ANGLE_FACTOR );
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			Angle key = (x>=0 ? (y>=0 ? 0 : 3) : (y>=0 ? 1 : 2));
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			return (theta<<2) | key;
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		}
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	}
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}
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#endif