#pragma once

#include "Vector3.h"

#include <array>





// fwd:
class cWorld;





// tolua_begin

class cTracer
{
public:

	/// Contains the position of the block that caused the collision
	Vector3f BlockHitPosition;

	/// Contains which face was hit
	Vector3f HitNormal;

	/// Contains the exact position where a collision occured. (BlockHitPosition + Offset on block)
	Vector3f RealHit;


	cTracer(cWorld * a_World);
	~cTracer();

	/// Determines if a collision occures along a line. Returns true if a collision occurs.
	bool Trace(const Vector3f & a_Start, const Vector3f & a_Direction, int a_Distance)
	{
		return Trace(a_Start, a_Direction, a_Distance, false);
	}

	/// Determines if a collision occures along a line. Returns true if a collision occurs.
	/// When a_LineOfSight is true, we don't use the standard collision detection rules. Instead we use
	/// the rules for monster vision. E.g. Only water and air do not block vision.
	/// a_Distance is the number of iterations (blocks hits) that are tested.
	bool Trace(const Vector3f & a_Start, const Vector3f & a_Direction, int a_Distance, bool a_LineOfSight);

private:

	/// Preps Tracer object for call of Trace function. Only used internally.
	void SetValues( const Vector3f & a_Start, const Vector3f & a_Direction);

	/// Calculates where on the block a collision occured, if it does occur
	/// Returns 0 if no intersection occured
	/// Returns 1 if an intersection occured at a single point
	/// Returns 2 if the line segment lies in the plane being checked
	int intersect3D_SegmentPlane( const Vector3f & a_Origin, const Vector3f & a_End, const Vector3f & a_PlanePos, const Vector3f & a_PlaneNormal);
	
	/// Determines which face on the block a collision occured, if it does occur
	/// Returns 0 if the block is air, water or no collision occured
	/// Return 1 through 6 for the following block faces, repectively: -x, -z, x, z, y, -y
	int GetHitNormal( const Vector3f & start, const Vector3f & end, const Vector3i &  a_BlockPos);

	/// Signum function
	int SigNum(float a_Num);

	cWorld * m_World;

	static const std::array<const Vector3f, 6> & m_NormalTable(void);

	Vector3f dir;
	Vector3f tDelta;
	Vector3i pos;
	Vector3i end1;
	Vector3i step;
	Vector3f tMax;
};

// tolua_end