diff --git a/src/p_enemy.cpp b/src/p_enemy.cpp
index 67ebdbfca..57b2200d2 100644
--- a/src/p_enemy.cpp
+++ b/src/p_enemy.cpp
@@ -885,11 +885,8 @@ void P_NewChaseDir(AActor * actor)
 		double deltay = 0;
 		while ((line = it.Next()))
 		{
-			if (line->backsector                     && // Ignore one-sided linedefs
-				box.Right()  > line->bbox[BOXLEFT]   &&
-				box.Left()   < line->bbox[BOXRIGHT]  &&
-				box.Top()    > line->bbox[BOXBOTTOM] && // Linedef must be contacted
-				box.Bottom() < line->bbox[BOXTOP]    &&
+			if (line->backsector  && // Ignore one-sided linedefs
+				box.inRange(line) &&
 				box.BoxOnLineSide(line) == -1)
 		    {
 				double front = line->frontsector->floorplane.ZatPoint(actor->PosRelative(line));
diff --git a/src/p_maputl.cpp b/src/p_maputl.cpp
index f6246b7a4..6dce13926 100644
--- a/src/p_maputl.cpp
+++ b/src/p_maputl.cpp
@@ -403,10 +403,10 @@ bool AActor::FixMapthingPos()
 			}
 
 			// Not inside the line's bounding box
-			if (_f_X() + _f_radius() <= ldef->bbox[BOXLEFT]
-				|| _f_X() - _f_radius() >= ldef->bbox[BOXRIGHT]
-				|| _f_Y() + _f_radius() <= ldef->bbox[BOXBOTTOM]
-				|| _f_Y() - _f_radius() >= ldef->bbox[BOXTOP])
+			if (X() + radius <= ldef->bbox[BOXLEFT]
+				|| X() - radius >= ldef->bbox[BOXRIGHT]
+				|| Y() + radius <= ldef->bbox[BOXBOTTOM]
+				|| Y() - radius >= ldef->bbox[BOXTOP])
 				continue;
 
 			// Get the exact distance to the line
diff --git a/src/p_setup.cpp b/src/p_setup.cpp
index e751957d3..91ea7086f 100644
--- a/src/p_setup.cpp
+++ b/src/p_setup.cpp
@@ -1905,26 +1905,26 @@ void P_AdjustLine (line_t *ld)
 
 	ld->setDelta(v2->fX() - v1->fX(), v2->fY() - v1->fY());
 	
-	if (v1->fixX() < v2->fixX())
+	if (v1->fX() < v2->fX())
 	{
-		ld->bbox[BOXLEFT] = v1->fixX();
-		ld->bbox[BOXRIGHT] = v2->fixX();
+		ld->bbox[BOXLEFT] = v1->fX();
+		ld->bbox[BOXRIGHT] = v2->fX();
 	}
 	else
 	{
-		ld->bbox[BOXLEFT] = v2->fixX();
-		ld->bbox[BOXRIGHT] = v1->fixX();
+		ld->bbox[BOXLEFT] = v2->fX();
+		ld->bbox[BOXRIGHT] = v1->fX();
 	}
 
-	if (v1->fixY() < v2->fixY())
+	if (v1->fY() < v2->fY())
 	{
-		ld->bbox[BOXBOTTOM] = v1->fixY();
-		ld->bbox[BOXTOP] = v2->fixY();
+		ld->bbox[BOXBOTTOM] = v1->fY();
+		ld->bbox[BOXTOP] = v2->fY();
 	}
 	else
 	{
-		ld->bbox[BOXBOTTOM] = v2->fixY();
-		ld->bbox[BOXTOP] = v1->fixY();
+		ld->bbox[BOXBOTTOM] = v2->fY();
+		ld->bbox[BOXTOP] = v1->fY();
 	}
 }
 
diff --git a/src/po_man.cpp b/src/po_man.cpp
index ca7a03f19..3a5ac69ad 100644
--- a/src/po_man.cpp
+++ b/src/po_man.cpp
@@ -168,6 +168,7 @@ public:
 // EXTERNAL FUNCTION PROTOTYPES --------------------------------------------
 
 void PO_Init (void);
+void P_AdjustLine(line_t *ld);
 
 // PRIVATE FUNCTION PROTOTYPES ---------------------------------------------
 
@@ -893,33 +894,7 @@ void FPolyObj::UpdateBBox ()
 {
 	for(unsigned i=0;i<Linedefs.Size(); i++)
 	{
-		line_t *line = Linedefs[i];
-
-		if (line->v1->fixX() < line->v2->fixX())
-		{
-			line->bbox[BOXLEFT] = line->v1->fixX();
-			line->bbox[BOXRIGHT] = line->v2->fixX();
-		}
-		else
-		{
-			line->bbox[BOXLEFT] = line->v2->fixX();
-			line->bbox[BOXRIGHT] = line->v1->fixX();
-		}
-		if (line->v1->fixY() < line->v2->fixY())
-		{
-			line->bbox[BOXBOTTOM] = line->v1->fixY();
-			line->bbox[BOXTOP] = line->v2->fixY();
-		}
-		else
-		{
-			line->bbox[BOXBOTTOM] = line->v2->fixY();
-			line->bbox[BOXTOP] = line->v1->fixY();
-		}
-
-		// Update the line's slopetype
-		line->setDelta(
-			line->v2->fixX() - line->v1->fixX(),
-			line->v2->fixY() - line->v1->fixY());
+		P_AdjustLine(Linedefs[i]);
 	}
 	CalcCenter();
 }
@@ -987,10 +962,10 @@ void FPolyObj::DoMovePolyobj (const DVector2 &pos)
 	}
 	for (unsigned i = 0; i < Linedefs.Size(); i++)
 	{
-		Linedefs[i]->bbox[BOXTOP] += FLOAT2FIXED(pos.Y);
-		Linedefs[i]->bbox[BOXBOTTOM] += FLOAT2FIXED(pos.Y);
-		Linedefs[i]->bbox[BOXLEFT] += FLOAT2FIXED(pos.X);
-		Linedefs[i]->bbox[BOXRIGHT] += FLOAT2FIXED(pos.X);
+		Linedefs[i]->bbox[BOXTOP] += pos.Y;
+		Linedefs[i]->bbox[BOXBOTTOM] += pos.Y;
+		Linedefs[i]->bbox[BOXLEFT] += pos.X;
+		Linedefs[i]->bbox[BOXRIGHT] += pos.X;
 	}
 }
 
@@ -1120,10 +1095,10 @@ bool FPolyObj::CheckMobjBlocking (side_t *sd)
 
 	ld = sd->linedef;
 
-	top = GetSafeBlockY(ld->bbox[BOXTOP]-bmaporgy);
-	bottom = GetSafeBlockY(ld->bbox[BOXBOTTOM]-bmaporgy);
-	left = GetSafeBlockX(ld->bbox[BOXLEFT]-bmaporgx);
-	right = GetSafeBlockX(ld->bbox[BOXRIGHT]-bmaporgx);
+	top = int((ld->bbox[BOXTOP] - FIXED2DBL(bmaporgy)) / 128.);
+	bottom = int((ld->bbox[BOXBOTTOM] - FIXED2DBL(bmaporgy)) / 128.);
+	left = int((ld->bbox[BOXLEFT] - FIXED2DBL(bmaporgx)) / 128.);
+	right = int((ld->bbox[BOXRIGHT] - FIXED2DBL(bmaporgx)) / 128.);
 
 	blocked = false;
 	checker.Clear();
@@ -1183,14 +1158,7 @@ bool FPolyObj::CheckMobjBlocking (side_t *sd)
 
 						FBoundingBox box(mobj->X(), mobj->Y(), mobj->radius);
 
-						if (box.Right() <= ld->bbox[BOXLEFT]
-							|| box.Left() >= ld->bbox[BOXRIGHT]
-							|| box.Top() <= ld->bbox[BOXBOTTOM]
-							|| box.Bottom() >= ld->bbox[BOXTOP])
-						{
-							continue;
-						}
-						if (box.BoxOnLineSide(ld) != -1)
+						if (!box.inRange(ld) || box.BoxOnLineSide(ld) != -1)
 						{
 							continue;
 						}
@@ -1648,10 +1616,10 @@ static void TranslateToStartSpot (int tag, const DVector2 &origin)
 	}
 	for (unsigned i = 0; i < po->Linedefs.Size(); i++)
 	{
-		po->Linedefs[i]->bbox[BOXTOP] -= FLOAT2FIXED(delta.Y);
-		po->Linedefs[i]->bbox[BOXBOTTOM] -= FLOAT2FIXED(delta.Y);
-		po->Linedefs[i]->bbox[BOXLEFT] -= FLOAT2FIXED(delta.X);
-		po->Linedefs[i]->bbox[BOXRIGHT] -= FLOAT2FIXED(delta.X);
+		po->Linedefs[i]->bbox[BOXTOP] -= delta.Y;
+		po->Linedefs[i]->bbox[BOXBOTTOM] -= delta.Y;
+		po->Linedefs[i]->bbox[BOXLEFT] -= delta.X;
+		po->Linedefs[i]->bbox[BOXRIGHT] -= delta.X;
 	}
 	for (unsigned i = 0; i < po->Vertices.Size(); i++)
 	{
diff --git a/src/portal.cpp b/src/portal.cpp
index 882b4da52..dab6bf009 100644
--- a/src/portal.cpp
+++ b/src/portal.cpp
@@ -1174,13 +1174,7 @@ bool P_CollectConnectedGroups(int startgroup, const fixedvec3 &position, fixed_t
 
 			FBoundingBox box(position.x + disp.pos.x, position.y + disp.pos.y, checkradius);
 
-			if (box.Right() <= ld->bbox[BOXLEFT]
-				|| box.Left() >= ld->bbox[BOXRIGHT]
-				|| box.Top() <= ld->bbox[BOXBOTTOM]
-				|| box.Bottom() >= ld->bbox[BOXTOP])
-				continue;	// not touched
-
-			if (box.BoxOnLineSide(linkedPortals[i]->mOrigin) != -1) continue;	// not touched
+			if (!box.inRange(ld) || box.BoxOnLineSide(linkedPortals[i]->mOrigin) != -1) continue;	// not touched
 			foundPortals.Push(linkedPortals[i]);
 		}
 		bool foundone = true;
@@ -1241,13 +1235,7 @@ bool P_CollectConnectedGroups(int startgroup, const fixedvec3 &position, fixed_t
 				line_t *ld;
 				while ((ld = it.Next()))
 				{
-					if (box.Right() <= ld->bbox[BOXLEFT]
-						|| box.Left() >= ld->bbox[BOXRIGHT]
-						|| box.Top() <= ld->bbox[BOXBOTTOM]
-						|| box.Bottom() >= ld->bbox[BOXTOP])
-						continue;
-
-					if (box.BoxOnLineSide(ld) != -1)
+					if (!box.inRange(ld) || box.BoxOnLineSide(ld) != -1)
 						continue;
 
 					if (!(thisgroup & FPortalGroupArray::LOWER))
diff --git a/src/r_defs.h b/src/r_defs.h
index 851fc2a7a..7814d2c11 100644
--- a/src/r_defs.h
+++ b/src/r_defs.h
@@ -1407,7 +1407,7 @@ public:
 	fixed_t		Alpha;		// <--- translucency (0=invisibile, FRACUNIT=opaque)
 	int			args[5];	// <--- hexen-style arguments (expanded to ZDoom's full width)
 	side_t		*sidedef[2];
-	fixed_t		bbox[4];	// bounding box, for the extent of the LineDef.
+	double		bbox[4];	// bounding box, for the extent of the LineDef.
 	sector_t	*frontsector, *backsector;
 	int 		validcount;	// if == validcount, already checked
 	int			locknumber;	// [Dusk] lock number for special
@@ -1672,10 +1672,10 @@ inline void AActor::ClearInterpolation()
 
 inline bool FBoundingBox::inRange(const line_t *ld) const
 {
-	return Left() < ld->bbox[BOXRIGHT] &&
-		Right() > ld->bbox[BOXLEFT] &&
-		Top() > ld->bbox[BOXBOTTOM] &&
-		Bottom() < ld->bbox[BOXTOP];
+	return FIXED2DBL(Left()) < ld->bbox[BOXRIGHT] &&
+		FIXED2DBL(Right()) > ld->bbox[BOXLEFT] &&
+		FIXED2DBL(Top()) > ld->bbox[BOXBOTTOM] &&
+		FIXED2DBL(Bottom()) < ld->bbox[BOXTOP];
 }