diff --git a/src/compatibility.cpp b/src/compatibility.cpp
index d60677f64..498fefb2a 100644
--- a/src/compatibility.cpp
+++ b/src/compatibility.cpp
@@ -145,6 +145,7 @@ static FCompatOption Options[] =
 	{ "badangles",				COMPATF2_BADANGLES, SLOT_COMPAT2 },
 	{ "floormove",				COMPATF2_FLOORMOVE, SLOT_COMPAT2 },
 	{ "soundcutoff",			COMPATF2_SOUNDCUTOFF, SLOT_COMPAT2 },
+	{ "pointonline",			COMPATF2_POINTONLINE, SLOT_COMPAT2 },
 
 	{ NULL, 0, 0 }
 };
diff --git a/src/d_main.cpp b/src/d_main.cpp
index 98be13e33..3b3cce1f4 100644
--- a/src/d_main.cpp
+++ b/src/d_main.cpp
@@ -561,7 +561,7 @@ CUSTOM_CVAR(Int, compatmode, 0, CVAR_ARCHIVE|CVAR_NOINITCALL)
 			COMPATF_TRACE|COMPATF_MISSILECLIP|COMPATF_SOUNDTARGET|COMPATF_NO_PASSMOBJ|COMPATF_LIMITPAIN|
 			COMPATF_DEHHEALTH|COMPATF_INVISIBILITY|COMPATF_CROSSDROPOFF|COMPATF_CORPSEGIBS|COMPATF_HITSCAN|
 			COMPATF_WALLRUN|COMPATF_NOTOSSDROPS|COMPATF_LIGHT|COMPATF_MASKEDMIDTEX;
-		w = COMPATF2_BADANGLES|COMPATF2_FLOORMOVE;
+		w = COMPATF2_BADANGLES|COMPATF2_FLOORMOVE|COMPATF2_POINTONLINE;
 		break;
 
 	case 3: // Boom compat mode
@@ -580,6 +580,7 @@ CUSTOM_CVAR(Int, compatmode, 0, CVAR_ARCHIVE|CVAR_NOINITCALL)
 	case 6:	// Boom with some added settings to reenable some 'broken' behavior
 		v = COMPATF_TRACE|COMPATF_SOUNDTARGET|COMPATF_BOOMSCROLL|COMPATF_MISSILECLIP|COMPATF_NO_PASSMOBJ|
 			COMPATF_INVISIBILITY|COMPATF_CORPSEGIBS|COMPATF_HITSCAN|COMPATF_WALLRUN|COMPATF_NOTOSSDROPS;
+		w = COMPATF2_POINTONLINE;
 		break;
 
 	}
@@ -622,6 +623,7 @@ CVAR (Flag, compat_maskedmidtex,		compatflags,  COMPATF_MASKEDMIDTEX);
 CVAR (Flag, compat_badangles,			compatflags2, COMPATF2_BADANGLES);
 CVAR (Flag, compat_floormove,			compatflags2, COMPATF2_FLOORMOVE);
 CVAR (Flag, compat_soundcutoff,			compatflags2, COMPATF2_SOUNDCUTOFF);
+CVAR (Flag, compat_pointonline,			compatflags2, COMPATF2_POINTONLINE);
 
 //==========================================================================
 //
diff --git a/src/doomdef.h b/src/doomdef.h
index c8aa66c17..802591386 100644
--- a/src/doomdef.h
+++ b/src/doomdef.h
@@ -340,6 +340,7 @@ enum
 	COMPATF2_BADANGLES		= 1 << 0,	// It is impossible to face directly NSEW.
 	COMPATF2_FLOORMOVE		= 1 << 1,	// Use the same floor motion behavior as Doom.
 	COMPATF2_SOUNDCUTOFF	= 1 << 2,	// Cut off sounds when an actor vanishes instead of making it owner-less
+	COMPATF2_POINTONLINE	= 1 << 3,	// Use original but buggy P_PointOnLineSide() and P_PointOnDivlineSide()
 };
 
 // Emulate old bugs for select maps. These are not exposed by a cvar
diff --git a/src/g_mapinfo.cpp b/src/g_mapinfo.cpp
index 49493667e..ac938797d 100644
--- a/src/g_mapinfo.cpp
+++ b/src/g_mapinfo.cpp
@@ -1333,6 +1333,7 @@ MapFlagHandlers[] =
 	{ "compat_badangles",				MITYPE_COMPATFLAG, 0, COMPATF2_BADANGLES },
 	{ "compat_floormove",				MITYPE_COMPATFLAG, 0, COMPATF2_FLOORMOVE },
 	{ "compat_soundcutoff",				MITYPE_COMPATFLAG, 0, COMPATF2_SOUNDCUTOFF },
+	{ "compat_pointonline",				MITYPE_COMPATFLAG, 0, COMPATF2_POINTONLINE },
 	{ "cd_start_track",					MITYPE_EATNEXT,	0, 0 },
 	{ "cd_end1_track",					MITYPE_EATNEXT,	0, 0 },
 	{ "cd_end2_track",					MITYPE_EATNEXT,	0, 0 },
diff --git a/src/p_local.h b/src/p_local.h
index a8aaaeb0d..0e06ad72b 100644
--- a/src/p_local.h
+++ b/src/p_local.h
@@ -240,7 +240,10 @@ fixed_t P_AproxDistance (fixed_t dx, fixed_t dy);
 
 inline int P_PointOnLineSide (fixed_t x, fixed_t y, const line_t *line)
 {
-	return DMulScale32 (y-line->v1->y, line->dx, line->v1->x-x, line->dy) > 0;
+	const SDWORD result = DMulScale32 (y-line->v1->y, line->dx, line->v1->x-x, line->dy);
+	return (compatflags2 & COMPATF2_POINTONLINE)
+		? result >= 0
+		: result > 0;
 }
 
 //==========================================================================
@@ -254,7 +257,10 @@ inline int P_PointOnLineSide (fixed_t x, fixed_t y, const line_t *line)
 
 inline int P_PointOnDivlineSide (fixed_t x, fixed_t y, const divline_t *line)
 {
-	return DMulScale32 (y-line->y, line->dx, line->x-x, line->dy) > 0;
+	const SDWORD result = DMulScale32 (y-line->y, line->dx, line->x-x, line->dy);
+	return (compatflags2 & COMPATF2_POINTONLINE)
+		? result >= 0
+		: result > 0;
 }
 
 //==========================================================================
diff --git a/wadsrc/static/menudef.txt b/wadsrc/static/menudef.txt
index f15f91dff..b1ca44de7 100644
--- a/wadsrc/static/menudef.txt
+++ b/wadsrc/static/menudef.txt
@@ -1303,6 +1303,7 @@ OptionMenu "CompatibilityOptions"
 	Option "Find shortest textures like Doom",			"compat_SHORTTEX", "YesNo"
 	Option "Use buggier stair building",				"compat_stairs", "YesNo"
 	Option "Use Doom's floor motion behavior",			"compat_floormove", "YesNo"
+	Option "Use Doom's point-on-line algorithm",		"compat_pointonline", "YesNo"
 	
 	StaticText " "
 	StaticText "Physics Behavior",1