(svn r21153) -Change: unify the moment trains/road vehicles become (un)visible when entering/leaving a tunnel. As a side effect some tunnel related glitches are gone.

src/saveload/afterload.cpp

@@ -2319,6 +2319,58 @@ bool AfterLoadGame()
 		}
 	}
 
+
+	if (CheckSavegameVersion(152)) {
+		/* The moment vehicles go from hidden to visible changed. This means
+		 * that vehicles don't always get visible anymore causing things to
+		 * get messed up just after loading the savegame. This fixes that. */
+		Vehicle *v;
+		FOR_ALL_VEHICLES(v) {
+			/* Is the vehicle in a tunnel? */
+			if (!IsTunnelTile(v->tile)) continue;
+
+			/* Is the vehicle actually at a tunnel entrance/exit? */
+			TileIndex vtile = TileVirtXY(v->x_pos, v->y_pos);
+			if (!IsTunnelTile(vtile)) continue;
+
+			/* Are we actually in this tunnel? Or maybe a lower tunnel? */
+			if (GetSlopeZ(v->x_pos, v->y_pos) != v->z_pos) continue;
+
+			/* What way are we going? */
+			const DiagDirection dir = GetTunnelBridgeDirection(vtile);
+			const DiagDirection vdir = DirToDiagDir(v->direction);
+
+			/* Have we passed the visibility "switch" state already? */
+			byte pos = (DiagDirToAxis(vdir) == AXIS_X ? v->x_pos : v->y_pos) & TILE_UNIT_MASK;
+			byte frame = (vdir == DIAGDIR_NE || vdir == DIAGDIR_NW) ? TILE_SIZE - 1 - pos : pos;
+			extern const byte _tunnel_visibility_frame[DIAGDIR_END];
+
+			if (dir == vdir && !(v->vehstatus & VS_HIDDEN)) {
+				if (frame < _tunnel_visibility_frame[dir]) continue;
+				/* Tunnel entrance, make us invisible. */
+				v->tile = vtile;
+				v->vehstatus |= VS_HIDDEN;
+
+				switch (v->type) {
+					case VEH_TRAIN: Train::From(v)->track       = TRACK_BIT_WORMHOLE; break;
+					case VEH_ROAD:  RoadVehicle::From(v)->state = RVSB_WORMHOLE;      break;
+					default: NOT_REACHED();
+				}
+			} else if (dir == ReverseDiagDir(vdir) && (v->vehstatus & VS_HIDDEN)) {
+				if (frame < TILE_SIZE - _tunnel_visibility_frame[dir]) continue;
+				/* Tunnel exit, make us visible again. */
+				v->tile = vtile;
+				v->vehstatus &= ~VS_HIDDEN;
+
+				switch (v->type) {
+					case VEH_TRAIN: Train::From(v)->track       = DiagDirToDiagTrackBits(vdir); break;
+					case VEH_ROAD:  RoadVehicle::From(v)->state = DiagDirToDiagTrackdir(vdir);  break;
+					default: NOT_REACHED();
+				}
+			}
+		}
+	}
+
 	/* Road stops is 'only' updating some caches */
 	AfterLoadRoadStops();
 	AfterLoadLabelMaps();

src/tunnelbridge_cmd.cpp

@@ -1489,30 +1489,14 @@ static void ChangeTileOwner_TunnelBridge(TileIndex tile, Owner old_owner, Owner
 static const byte TUNNEL_SOUND_FRAME = 1;
 
 /**
- * Frame when a train should be hidden in a tunnel with a certain direction.
+ * Frame when a vehicle should be hidden in a tunnel with a certain direction.
  * This differs per direction, because of visibility / bounding box issues.
  * Note that direction, in this case, is the direction leading into the tunnel.
- * When entering a tunnel, hide the train when it reaches the given frame.
- * When leaving a tunnel, show the train when it is one frame further
+ * When entering a tunnel, hide the vehicle when it reaches the given frame.
+ * When leaving a tunnel, show the vehicle when it is one frame further
  * to the 'outside', i.e. at (TILE_SIZE-1) - (frame) + 1
  */
-static const byte _train_tunnel_frame[DIAGDIR_END] = {14, 9, 7, 12};
-
-/**
- * Frame when a road vehicle enters a tunnel with a certain direction.
- * This differs per direction, like for trains. To make it even more fun,
- * the entry and exit frames are not consistent. This is the entry frame,
- * the road vehicle should be hidden when it reaches this frame.
- */
-static const byte _road_enter_tunnel_frame[DIAGDIR_END] = {13, 8, 8, 13};
-
-/**
- * Frame when a road vehicle exits a tunnel with a certain direction.
- * Note that 'direction' refers to the tunnel direction, not the
- * vehicle direction. As stated above, this frame is not the same as the
- * entry frame, for unclear (historical?) reasons.
- */
-static const byte _road_exit_tunnel_frame[DIAGDIR_END] = {2, 7, 9, 4};
+extern const byte _tunnel_visibility_frame[DIAGDIR_END] = {12, 8, 8, 12};
 
 static VehicleEnterTileStatus VehicleEnter_TunnelBridge(Vehicle *v, TileIndex tile, int x, int y)
 {
@@ -1539,7 +1523,7 @@ static VehicleEnterTileStatus VehicleEnter_TunnelBridge(Vehicle *v, TileIndex ti
 					}
 					return VETSB_CONTINUE;
 				}
-				if (frame == _train_tunnel_frame[dir]) {
+				if (frame == _tunnel_visibility_frame[dir]) {
 					t->tile = tile;
 					t->track = TRACK_BIT_WORMHOLE;
 					t->vehstatus |= VS_HIDDEN;
@@ -1547,7 +1531,7 @@ static VehicleEnterTileStatus VehicleEnter_TunnelBridge(Vehicle *v, TileIndex ti
 				}
 			}
 
-			if (dir == ReverseDiagDir(vdir) && frame == TILE_SIZE - _train_tunnel_frame[dir] && z == 0) {
+			if (dir == ReverseDiagDir(vdir) && frame == TILE_SIZE - _tunnel_visibility_frame[dir] && z == 0) {
 				/* We're at the tunnel exit ?? */
 				t->tile = tile;
 				t->track = DiagDirToDiagTrackBits(vdir);
@@ -1560,7 +1544,7 @@ static VehicleEnterTileStatus VehicleEnter_TunnelBridge(Vehicle *v, TileIndex ti
 
 			/* Enter tunnel? */
 			if (rv->state != RVSB_WORMHOLE && dir == vdir) {
-				if (frame == _road_enter_tunnel_frame[dir]) {
+				if (frame == _tunnel_visibility_frame[dir]) {
 					/* Frame should be equal to the next frame number in the RV's movement */
 					assert(frame == rv->frame + 1);
 					rv->tile = tile;
@@ -1573,7 +1557,7 @@ static VehicleEnterTileStatus VehicleEnter_TunnelBridge(Vehicle *v, TileIndex ti
 			}
 
 			/* We're at the tunnel exit ?? */
-			if (dir == ReverseDiagDir(vdir) && frame == _road_exit_tunnel_frame[dir] && z == 0) {
+			if (dir == ReverseDiagDir(vdir) && frame == TILE_SIZE - _tunnel_visibility_frame[dir] && z == 0) {
 				rv->tile = tile;
 				rv->state = DiagDirToDiagTrackdir(vdir);
 				rv->frame = frame;