//###########################################################################
//
// $Workfile:   RAY.HPP  $
// $Revision:   1.5  $
//  $Modtime:   14 May 1996 20:06:14  $
//
//~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
// Copyright(c) 1993 J. M. Albertson - All Rights Reserved
//
//###########################################################################

#if !defined(RAY_HPP)
#	define RAY_HPP

#	if !defined(POINT3D_HPP)
#		include <point3d.hpp>
#	endif

#	if !defined(UNITVEC_HPP)
#		include <unitvec.hpp>
#	endif

	class Plane;
	class Sphere;
	class Cylinder;
	class Cone;

	//~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Ray ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

	class Ray SIGNATURED
	{
	 public:
		Point3D
			origin;
		UnitVector
			direction;

		Ray()
			{}
		Ray(
			const Point3D &origin,
			const UnitVector &direction
		):
			origin(origin),
			direction(direction)
				{}

		//
		// Ray projection functions
		//
		void
			Project(
				Scalar length,
				Point3D *result
			);
		Scalar
			LengthToClosestPointTo(const Point3D &point);
		void
			ClosestPointTo(
				const Point3D &point,
				Point3D *result
			)
				{
					Check(this); Check(result); Check(&point);
					Project(LengthToClosestPointTo(point),result);
				}

		//
		// Ray intersection functions
		//
		Scalar
			DistanceTo(
				const Plane &plane,
				Scalar *product
			) const;
		Scalar
			DistanceTo(
				const Sphere &sphere,
				Scalar *penetration
			) const;

		//
		// Test support
		//
		Logical
			TestInstance() const;
		static Logical
			TestClass();
	};

	extern Scalar
		Find_Closest_Approach(
			const Point3D& origin1,
			const Vector3D& velocity1,
			Point3D *result1,
			const Point3D& origin2,
			const Vector3D& velocity2,
			Point3D *result2,
			Scalar *time,
			Logical *constant
		);

#endif