AABB - Line Segment intersection test

static bool RaySlabIntersect(float slabmin, float slabmax, float raystart, float rayend, float& tbenter, float& tbexit){	float raydir = rayend - raystart;	// ray parallel to the slab	if (fabs(raydir) < 1.0E-9f)	{		// ray parallel to the slab, but ray not inside the slab planes		if(raystart < slabmin || raystart > slabmax)		{			return false;		}		// ray parallel to the slab, but ray inside the slab planes		else		{			return true;		}	}	// slab's enter and exit parameters	float tsenter = (slabmin - raystart) / raydir;	float tsexit = (slabmax - raystart) / raydir;	// order the enter / exit values.	if(tsenter > tsexit)	{		swapf(tsenter, tsexit);	}	// make sure the slab interval and the current box intersection interval overlap	if (tbenter > tsexit || tsenter > tbexit)	{		// nope. Ray missed the box.		return false;	}	// yep, the slab and current intersection interval overlap	else	{		// update the intersection interval		tbenter = max(tbenter, tsenter);		tbexit = min(tbexit, tsexit);		return true;	}}static bool SegmentAABBoxIntersect(const CAABBox1& Box, const CSegment1& Seg, float &tinter){	// initialise to the segment's boundaries. 	float tenter = 0.0f, texit = 1.0f; 	// test X slab	if (!RaySlabIntersect(Box.Min.x, Box.Max.x, Seg.Start.x, Seg.End.x, tenter, texit)) 	{		return false;	}	// test Y slab	if (!RaySlabIntersect(Box.Min.y, Box.Max.y, Seg.Start.y, Seg.End.y, tenter, texit)) 	{		return false;	}	// test Z slab	if (!RaySlabIntersect(Box.Min.z, Box.Max.z, Seg.Start.z, Seg.End.z, tenter, texit)) 	{		return false;	}	// all intersections in the green. Return the first time of intersection, tenter.	tinter = tenter;	return  true;}

bool Intersection::Intersect(const Vector3& p1, const Vector3& p2, const Vector3& min, const Vector3& max){    Vector3 d = (p2 - p1) * 0.5f;    Vector3 e = (max - min) * 0.5f;    Vector3 c = p1 + d - (min + max) * 0.5f;    Vector3 ad = d.Absolute(); // Returns same vector with all components positive    if (fabsf(c[0]) > e[0] + ad[0])        return false;    if (fabsf(c[1]) > e[1] + ad[1])        return false;    if (fabsf(c[2]) > e[2] + ad[2])        return false;      if (fabsf(d[1] * c[2] - d[2] * c[1]) > e[1] * ad[2] + e[2] * ad[1] + EPSILON)        return false;    if (fabsf(d[2] * c[0] - d[0] * c[2]) > e[2] * ad[0] + e[0] * ad[2] + EPSILON)        return false;    if (fabsf(d[0] * c[1] - d[1] * c[0]) > e[0] * ad[1] + e[1] * ad[0] + EPSILON)        return false;                return true;}

template <class T> bool IntersectLineAABB(    const Vector3<T>& O,    const Vector3<T>& D,    const Vector3<T>& min,    const Vector3<T>& max,    T t[],    T epsilon){    Vector3<T> C = (min + max) * (T)0.5;    Vector3<T> e = (max - min) * (T)0.5;    int parallel = 0;    bool found = false;    Vector3<T> d = C - O;    for (int i = 0; i < 3; ++i)    {        if (Math<T>::Fabs(D) < epsilon)            parallel |= 1 << i;        else        {            T es = (D > (T)0.0) ? e : -e;            T invDi = (T)1.0 / D;            if (!found)            {                t[0] = (d - es) * invDi;                t[1] = (d + es) * invDi;                found = true;            }            else            {                T s = (d - es) * invDi;                if (s > t[0])                    t[0] = s;                s = (d + es) * invDi;                if (s < t[1])                    t[1] = s;                if (t[0] > t[1])                    return false;            }        }    }        if (parallel)        for (int i = 0; i < 3; ++i)            if (parallel & (1 << i))                if (Math<T>::Fabs(d - t[0] * D) > e || Math<T>::Fabs(d - t[1] * D) > e)                    return false;    return true;}