- let's save the terrain properties as names so that they survive a change in the definition files.

src/p_terrain.cpp

@@ -46,6 +46,7 @@
 #include "s_sound.h"
 #include "p_local.h"
 #include "templates.h"
+#include "farchive.h"
 
 // MACROS ------------------------------------------------------------------
 
@@ -704,3 +705,26 @@ int P_FindTerrain (FName name)
 	}
 	return -1;
 }
+
+void P_SerializeTerrain(FArchive &arc, int &terrainnum)
+{
+	FName val;
+	if (arc.IsStoring())
+	{
+		if (terrainnum < 0 || terrainnum >= (int)Terrains.Size())
+		{
+			val = NAME_Null;
+		}
+		else
+		{
+			val = Terrains[terrainnum].Name;
+		}
+		arc << val;
+	}
+	else
+	{
+		arc << val;
+		terrainnum = P_FindTerrain(val);
+
+	}
+}