Splits part of PTR_SlideTraverse into a lua-exposed function, exposes P_RailThinker

src/lua_baselib.c

@@ -681,6 +681,17 @@ static int lib_pSpawnPlayerMissile(lua_State *L)
 	return 1;
 }
 
+static int lib_pRailThinker(lua_State *L)
+{
+	mobj_t *mobj = *((mobj_t **)luaL_checkudata(L, 1, META_MOBJ));
+	NOHUD
+	INLEVEL
+	if (!mobj)
+		return LUA_ErrInvalid(L, "mobj_t");
+	lua_pushboolean(L, P_RailThinker(mobj));
+	return 1;
+}
+
 static int lib_pMobjFlip(lua_State *L)
 {
 	mobj_t *mobj = *((mobj_t **)luaL_checkudata(L, 1, META_MOBJ));
@@ -1406,6 +1417,19 @@ static int lib_pTeleportMove(lua_State *L)
 	return 2;
 }
 
+static int lib_pCheckMoveBlocked(lua_State *L)
+{
+	line_t *li = luaL_checkudata(L, 1, META_LINE);
+	mobj_t *mo = *((mobj_t **)luaL_checkudata(L, 2, META_MOBJ));
+	INLEVEL
+	if (!li)
+		return LUA_ErrInvalid(L, "line_t");
+	if (!mo)
+		return LUA_ErrInvalid(L, "mobj_t");
+	lua_pushboolean(L, P_CheckMoveBlocked(li, mo));
+	return 1;
+}
+
 static int lib_pSlideMove(lua_State *L)
 {
 	mobj_t *mo = *((mobj_t **)luaL_checkudata(L, 1, META_MOBJ));
@@ -2979,6 +3003,7 @@ static luaL_Reg lib[] = {
 	{"P_ColorTeamMissile",lib_pColorTeamMissile},
 	{"P_SPMAngle",lib_pSPMAngle},
 	{"P_SpawnPlayerMissile",lib_pSpawnPlayerMissile},
+	{"P_RailThinker",lib_pRailThinker},
 	{"P_MobjFlip",lib_pMobjFlip},
 	{"P_GetMobjGravity",lib_pGetMobjGravity},
 	{"P_WeaponOrPanel",lib_pWeaponOrPanel},
@@ -3041,6 +3066,7 @@ static luaL_Reg lib[] = {
 	{"P_TryMove",lib_pTryMove},
 	{"P_Move",lib_pMove},
 	{"P_TeleportMove",lib_pTeleportMove},
+	{"P_CheckMoveBlocked",lib_pCheckMoveBlocked},
 	{"P_SlideMove",lib_pSlideMove},
 	{"P_BounceMove",lib_pBounceMove},
 	{"P_CheckSight", lib_pCheckSight},

src/p_local.h

@@ -403,6 +403,7 @@ boolean P_CheckCameraPosition(fixed_t x, fixed_t y, camera_t *thiscam);
 boolean P_TryMove(mobj_t *thing, fixed_t x, fixed_t y, boolean allowdropoff);
 boolean P_Move(mobj_t *actor, fixed_t speed);
 boolean P_TeleportMove(mobj_t *thing, fixed_t x, fixed_t y, fixed_t z);
+boolean P_CheckMoveBlocked(line_t *li, mobj_t *mo);
 void P_SlideMove(mobj_t *mo);
 void P_BounceMove(mobj_t *mo);
 boolean P_CheckSight(mobj_t *t1, mobj_t *t2);

src/p_map.c

@@ -3367,6 +3367,45 @@ static boolean P_IsClimbingValid(player_t *player, angle_t angle)
 	return false;
 }
 
+//
+//P_CheckMoveBlocked
+//
+boolean P_CheckMoveBlocked(line_t *li, mobj_t *mo)
+{
+	// one-sided linedefs are always solid to sliding movement.
+	// one-sided linedef
+	if (!li->backsector)
+	{
+		if (P_PointOnLineSide(mo->x, mo->y, li))
+			return true; // don't hit the back side
+		return false;
+	}
+
+	if (!(mo->flags & MF_MISSILE))
+	{
+		if (li->flags & ML_IMPASSIBLE)
+			return false;
+
+		if ((mo->flags & (MF_ENEMY|MF_BOSS)) && li->flags & ML_BLOCKMONSTERS)
+			return false;
+	}
+
+	// set openrange, opentop, openbottom
+	P_LineOpening(li, mo);
+
+	if (openrange < mo->height)
+		return false; // doesn't fit
+
+	if (opentop - mo->z < mo->height)
+		return false; // mobj is too high
+
+	if (openbottom - mo->z > FixedMul(MAXSTEPMOVE, mo->scale))
+		return false; // too big a step up
+
+	// this line doesn't block movement
+	return true;
+}
+
 //
 // PTR_SlideTraverse
 //
@@ -3378,42 +3417,10 @@ static boolean PTR_SlideTraverse(intercept_t *in)
 
 	li = in->d.line;
 
-	// one-sided linedefs are always solid to sliding movement.
+	if (!P_CheckMoveBlocked(li, slidemo))
-	// one-sided linedef
-	if (!li->backsector)
 	{
-		if (P_PointOnLineSide(slidemo->x, slidemo->y, li))
-			return true; // don't hit the back side
-		goto isblocking;
-	}
-
-	if (!(slidemo->flags & MF_MISSILE))
-	{
-		if (li->flags & ML_IMPASSIBLE)
-			goto isblocking;
-
-		if ((slidemo->flags & (MF_ENEMY|MF_BOSS)) && li->flags & ML_BLOCKMONSTERS)
-			goto isblocking;
-	}
-
-	// set openrange, opentop, openbottom
-	P_LineOpening(li, slidemo);
-
-	if (openrange < slidemo->height)
-		goto isblocking; // doesn't fit
-
-	if (opentop - slidemo->z < slidemo->height)
-		goto isblocking; // mobj is too high
-
-	if (openbottom - slidemo->z > FixedMul(MAXSTEPMOVE, slidemo->scale))
-		goto isblocking; // too big a step up
-
-	// this line doesn't block movement
-	return true;
-
 		// the line does block movement,
 		// see if it is closer than best so far
-isblocking:
 		if (li->polyobj && slidemo->player)
 		{
 			if ((li->polyobj->lines[0]->backsector->flags & SF_TRIGGERSPECIAL_TOUCH) && !(li->polyobj->flags & POF_NOSPECIALS))
@@ -3536,6 +3543,8 @@ isblocking:
 
 		return false; // stop
 	}
+	return true; // keep going!
+}
 
 //
 // P_SlideCameraMove