mobj_t: add owner member

src/lua_mobjlib.c

@@ -109,6 +109,7 @@ enum mobj_e {
 	mobj_stringargs,
 	mobj_reappear,
 	mobj_punt_ref,
+	mobj_owner,
 };
 
 static const char *const mobj_opt[] = {
@@ -198,6 +199,7 @@ static const char *const mobj_opt[] = {
 	"stringargs",
 	"reappear",
 	"punt_ref",
+	"owner",
 	NULL};
 
 #define UNIMPLEMENTED luaL_error(L, LUA_QL("mobj_t") " field " LUA_QS " is not implemented for Lua and cannot be accessed.", mobj_opt[field])
@@ -508,6 +510,14 @@ static int mobj_get(lua_State *L)
 		}
 		LUA_PushUserdata(L, mo->punt_ref, META_MOBJ);
 		break;
+	case mobj_owner:
+		if (mo->owner && P_MobjWasRemoved(mo->owner))
+		{ // don't put invalid mobj back into Lua.
+			P_SetTarget(&mo->owner, NULL);
+			return 0;
+		}
+		LUA_PushUserdata(L, mo->owner, META_MOBJ);
+		break;
 	default: // extra custom variables in Lua memory
 		lua_getfield(L, LUA_REGISTRYINDEX, LREG_EXTVARS);
 		I_Assert(lua_istable(L, -1));
@@ -910,6 +920,15 @@ static int mobj_set(lua_State *L)
 			P_SetTarget(&mo->punt_ref, punt_ref);
 		}
 		break;
+	case mobj_owner:
+		if (lua_isnil(L, 3))
+			P_SetTarget(&mo->owner, NULL);
+		else
+		{
+			mobj_t *owner = *((mobj_t **)luaL_checkudata(L, 3, META_MOBJ));
+			P_SetTarget(&mo->owner, owner);
+		}
+		break;
 	default:
 		lua_getfield(L, LUA_REGISTRYINDEX, LREG_EXTVARS);
 		I_Assert(lua_istable(L, -1));

src/p_mobj.c

@@ -10252,6 +10252,8 @@ void P_MobjThinker(mobj_t *mobj)
 		P_SetTarget(&mobj->itnext, NULL);
 	if (mobj->punt_ref && P_MobjWasRemoved(mobj->punt_ref))
 		P_SetTarget(&mobj->punt_ref, NULL);
+	if (mobj->owner && P_MobjWasRemoved(mobj->owner))
+		P_SetTarget(&mobj->owner, NULL);
 
 	if (mobj->flags & MF_NOTHINK)
 		return;
@@ -11807,6 +11809,7 @@ void P_RemoveMobj(mobj_t *mobj)
 
 	P_SetTarget(&mobj->itnext, NULL);
 	P_SetTarget(&mobj->punt_ref, NULL);
+	P_SetTarget(&mobj->owner, NULL);
 
 	P_RemoveThingTID(mobj);
 	P_DeleteMobjStringArgs(mobj);

src/p_mobj.h

@@ -445,6 +445,8 @@ struct mobj_t
 	// If punt_ref, set punt_ref->reappear, treat as if this->reappear
 	mobj_t *punt_ref;
 
+	mobj_t *owner;
+
 	// WARNING: New fields must be added separately to savegame and Lua.
 };
 

src/p_saveg.c

@@ -2676,6 +2676,7 @@ typedef enum
 	MD3_LIGHTLEVEL		= 1,
 	MD3_REAPPEAR		= 1<<1,
 	MD3_PUNT_REF		= 1<<2,
+	MD3_OWNER			= 1<<3,
 } mobj_diff3_t;
 
 typedef enum
@@ -3000,6 +3001,8 @@ static void SaveMobjThinker(savebuffer_t *save, const thinker_t *th, const UINT8
 		diff3 |= MD3_REAPPEAR;
 	if (mobj->punt_ref)
 		diff3 |= MD3_PUNT_REF;
+	if (mobj->owner)
+		diff3 |= MD3_OWNER;
 
 	if (diff3 != 0)
 		diff2 |= MD2_MORE;
@@ -3288,6 +3291,10 @@ static void SaveMobjThinker(savebuffer_t *save, const thinker_t *th, const UINT8
 	{
 		WRITEUINT32(save->p, mobj->punt_ref->mobjnum);
 	}
+	if (diff3 & MD3_OWNER)
+	{
+		WRITEUINT32(save->p, mobj->owner->mobjnum);
+	}
 
 	WRITEUINT32(save->p, mobj->mobjnum);
 }
@@ -4542,6 +4549,10 @@ static thinker_t* LoadMobjThinker(savebuffer_t *save, actionf_p1 thinker)
 	{
 		mobj->punt_ref = (mobj_t *)(size_t)READUINT32(save->p);
 	}
+	if (diff3 & MD3_OWNER)
+	{
+		mobj->owner = (mobj_t *)(size_t)READUINT32(save->p);
+	}
 
 	// set sprev, snext, bprev, bnext, subsector
 	P_SetThingPosition(mobj);
@@ -5589,6 +5600,13 @@ static void P_RelinkPointers(void)
 			if (!P_SetTarget(&mobj->punt_ref, P_FindNewPosition(temp)))
 				CONS_Debug(DBG_GAMELOGIC, "punt_ref not found on %d\n", mobj->type);
 		}
+		if (mobj->owner)
+		{
+			temp = (UINT32)(size_t)mobj->owner;
+			mobj->owner = NULL;
+			if (!P_SetTarget(&mobj->owner, P_FindNewPosition(temp)))
+				CONS_Debug(DBG_GAMELOGIC, "owner not found on %d\n", mobj->type);
+		}
 	}
 
 	for (i = 0; i < MAXPLAYERS; i++)