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#ifndef __CGLA_UNITVECTOR_H_
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#define __CGLA_UNITVECTOR_H_
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#include "CGLA.h"
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#include "Vec3f.h"
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#include "TableTrigonometry.h"
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namespace CGLA
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{
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	namespace TT=TableTrigonometry;
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	/** The UnitVector stores a unit length vector as two angles.
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	A vector stored as two (fix point) angles is much smaller than
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	vector stored in the usual way. On a 32 bit architecture this
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	class should take up four bytes. not too bad. */
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	class UnitVector
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	{
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		TT::Angle theta, phi;
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		void encode(const Vec3f& v)
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		{
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#ifndef OLD_C_HEADERS
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			theta = TT::t_atan(std::sqrt(CGLA::sqr(v[0])+CGLA::sqr(v[1])), v[2]);
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#else
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			theta = TT::t_atan(sqrt(CGLA::sqr(v[0])+CGLA::sqr(v[1])), v[2]);
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#endif
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			phi   = TT::t_atan(v[0],v[1]);
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		}
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	public:
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		/// Construct unitvector from normal vector
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		explicit UnitVector(const Vec3f& v) {encode(v);}
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		/// Construct default unit vector
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		explicit UnitVector(): theta(0), phi(0) {}
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		/// Get theta angle
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		float t() const {return TT::angle2float(theta);}
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		/// Get phi angle
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		float f() const {return TT::angle2float(phi);}
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		/// Reconstruct Vec3f from unit vector
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		operator Vec3f() const
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		{
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			float costf = TT::t_cos(theta);
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			return Vec3f(TT::t_cos(phi)*costf ,
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									 TT::t_sin(phi)*costf,
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									 TT::t_sin(theta));
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		}
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		/// Test for equality.
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		bool operator==(const UnitVector& u) const
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		{
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			return theta == u.theta && phi == u.phi;
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		}
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	};
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	/// Inline output operator.
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	inline std::ostream& operator<<(std::ostream& os, const UnitVector& u)
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	{
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		os << "<v=" << u.t() << " h=" << u.f() << ">";
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		return os;
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	}
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}
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#endif