P_SpawnMapThing, P_RaiseTaggedThingsToFakeFloor: save raised Z position for respawning later

P_RespawnSpecials just calls P_SpawnMapThing again, so
this works.

src/doomdata.h

@@ -278,6 +278,7 @@ struct mapthing_t
 	char *script_stringargs[NUM_SCRIPT_STRINGARGS];
 	UINT8 layer; // FOF layer to spawn on, see P_GetMobjSpawnHeight
 	mapUserProperties_t user; // UDMF user-defined custom properties.
+	fixed_t adjusted_z; // Z adjusted on map load, used for respawning
 	mobj_t *mobj;
 };
 

src/p_mobj.c

@@ -13910,7 +13910,16 @@ mobj_t *P_SpawnMapThing(mapthing_t *mthing)
 
 	x = mthing->x << FRACBITS;
 	y = mthing->y << FRACBITS;
-	z = P_GetMapThingSpawnHeight(i, mthing, x, y);
+
+	if (mthing->adjusted_z != INT32_MAX)
+	{
+		z = mthing->adjusted_z;
+	}
+	else
+	{
+		z = P_GetMapThingSpawnHeight(i, mthing, x, y);
+	}
+
 	return P_SpawnMobjFromMapThing(mthing, x, y, z, i);
 }
 

src/p_setup.c

@@ -1356,6 +1356,8 @@ static void P_LoadThings(UINT8 *data)
 		else
 			mt->z = mt->options >> ZSHIFT;
 
+		mt->adjusted_z = INT32_MAX;
+
 		mt->mobj = NULL;
 	}
 }
@@ -3239,6 +3241,7 @@ static void P_LoadTextmap(void)
 		memset(mt->script_args, 0, NUM_SCRIPT_ARGS*sizeof(*mt->script_args));
 		memset(mt->script_stringargs, 0x00, NUM_SCRIPT_STRINGARGS*sizeof(*mt->script_stringargs));
 		mt->layer = 0;
+		mt->adjusted_z = INT32_MAX;
 		mt->mobj = NULL;
 
 		K_UserPropertiesClear(&mt->user);

src/p_spec.c

@@ -6256,6 +6256,8 @@ P_RaiseTaggedThingsToFakeFloor (
 					offset = mo->z - mo->floorz;
 					mo->z = P_GetZAt(control->c_slope, mo->x, mo->y, control->ceilingheight) + offset;
 				}
+
+				mthing->adjusted_z = mo->z;
 			}
 		}
 	}