Chunnel: Fix setting of tunnel ID in load conversion, add method to set ID.

src/saveload/afterload.cpp

@@ -58,6 +58,7 @@
 #include "../error.h"
 #include "../disaster_vehicle.h"
 #include "../tracerestrict.h"
+#include "../tunnel_map.h"
 
 
 #include "saveload_internal.h"
@@ -2047,8 +2048,8 @@ bool AfterLoadGame()
 
 					const Tunnel *t = new Tunnel(start_tile, end_tile, false);
 
-					_m[start_tile].m2 = t->index;
-					_m[end_tile].m2 = t->index;
+					SetTunnelIndex(start_tile, t->index);
+					SetTunnelIndex(end_tile, t->index);
 				}
 			}
 		}

src/tunnel_map.h

@@ -58,6 +58,18 @@ static inline TunnelID GetTunnelIndex(TileIndex t)
 TileIndex GetOtherTunnelEnd(TileIndex);
 bool IsTunnelInWay(TileIndex, int z, bool chunnel_allowed = false);
 
+/**
+ * Set the index of tunnel tile.
+ * @param t the tile
+ * @param id the tunnel ID
+ * @pre IsTunnelTile(t)
+ */
+static inline void SetTunnelIndex(TileIndex t, TunnelID id)
+{
+	assert(IsTunnelTile(t));
+	_m[t].m2 = (id >= TUNNEL_ID_MAP_LOOKUP) ? TUNNEL_ID_MAP_LOOKUP : id;
+}
+
 /**
  * Makes a road tunnel entrance
  * @param t the entrance of the tunnel
@@ -70,12 +82,12 @@ static inline void MakeRoadTunnel(TileIndex t, Owner o, TunnelID id, DiagDirecti
 {
 	SetTileType(t, MP_TUNNELBRIDGE);
 	SetTileOwner(t, o);
-	_m[t].m2 = (id >= TUNNEL_ID_MAP_LOOKUP) ? TUNNEL_ID_MAP_LOOKUP : id;
 	_m[t].m3 = 0;
 	_m[t].m4 = 0;
 	_m[t].m5 = TRANSPORT_ROAD << 2 | d;
 	SB(_me[t].m6, 2, 4, 0);
 	_me[t].m7 = 0;
+	SetTunnelIndex(t, id);
 	SetRoadOwner(t, ROADTYPE_ROAD, o);
 	if (o != OWNER_TOWN) SetRoadOwner(t, ROADTYPE_TRAM, o);
 	SetRoadTypes(t, r);
@@ -93,7 +105,6 @@ static inline void MakeRailTunnel(TileIndex t, Owner o, TunnelID id, DiagDirecti
 {
 	SetTileType(t, MP_TUNNELBRIDGE);
 	SetTileOwner(t, o);
-	_m[t].m2 = (id >= TUNNEL_ID_MAP_LOOKUP) ? TUNNEL_ID_MAP_LOOKUP : id;
 	SB(_m[t].m1, 7, 1, GB(r, 4, 1));
 	SB(_m[t].m3, 0, 4, GB(r, 0, 4));
 	SB(_m[t].m3, 4, 4, 0);
@@ -101,6 +112,7 @@ static inline void MakeRailTunnel(TileIndex t, Owner o, TunnelID id, DiagDirecti
 	_m[t].m5 = TRANSPORT_RAIL << 2 | d;
 	SB(_me[t].m6, 2, 4, 0);
 	_me[t].m7 = 0;
+	SetTunnelIndex(t, id);
 }
 
 #endif /* TUNNEL_MAP_H */