Fix: Try all possible reverse directions when a ship reaches a dead end

1 files changed, 17 insertions, 4 deletions

diff --git a/src/ship_cmd.cpp b/src/ship_cmd.cpp
index 0d8cd6c37..7f9dab0f1 100644
--- a/src/ship_cmd.cpp
+++ b/src/ship_cmd.cpp
@@ -335,13 +335,13 @@ static Vehicle *EnsureNoMovingShipProc(Vehicle *v, void *data)
 	return v->type == VEH_SHIP && (v->vehstatus & (VS_HIDDEN | VS_STOPPED)) == 0 ? v : nullptr;
 }
 
-static bool CheckReverseShip(const Ship *v)
+static bool CheckReverseShip(const Ship *v, Trackdir *trackdir = nullptr)
 {
 	/* Ask pathfinder for best direction */
 	bool reverse = false;
 	switch (_settings_game.pf.pathfinder_for_ships) {
-		case VPF_NPF: reverse = NPFShipCheckReverse(v); break;
-		case VPF_YAPF: reverse = YapfShipCheckReverse(v); break;
+		case VPF_NPF: reverse = NPFShipCheckReverse(v, trackdir); break;
+		case VPF_YAPF: reverse = YapfShipCheckReverse(v, trackdir); break;
 		default: NOT_REACHED();
 	}
 	return reverse;
@@ -725,7 +725,19 @@ static void ShipController(Ship *v)
 			DiagDirection diagdir = DiagdirBetweenTiles(gp.old_tile, gp.new_tile);
 			assert(diagdir != INVALID_DIAGDIR);
 			tracks = GetAvailShipTracks(gp.new_tile, diagdir);
-			if (tracks == TRACK_BIT_NONE) goto reverse_direction;
+			if (tracks == TRACK_BIT_NONE) {
+				Trackdir trackdir = INVALID_TRACKDIR;
+				CheckReverseShip(v, &trackdir);
+				if (trackdir == INVALID_TRACKDIR) goto reverse_direction;
+				static const Direction _trackdir_to_direction[] = {
+					DIR_NE, DIR_SE, DIR_E, DIR_E, DIR_S, DIR_S, INVALID_DIR, INVALID_DIR,
+					DIR_SW, DIR_NW, DIR_W, DIR_W, DIR_N, DIR_N, INVALID_DIR, INVALID_DIR,
+				};
+				v->direction = _trackdir_to_direction[trackdir];
+				assert(v->direction != INVALID_DIR);
+				v->state = TrackdirBitsToTrackBits(TrackdirToTrackdirBits(trackdir));
+				goto direction_changed;
+			}
 
 			/* Choose a direction, and continue if we find one */
 			track = ChooseShipTrack(v, gp.new_tile, diagdir, tracks);
@@ -796,6 +808,7 @@ getout:
 
 reverse_direction:
 	v->direction = ReverseDir(v->direction);
+direction_changed:
 	/* Remember our current location to avoid movement glitch */
 	v->rotation_x_pos = v->x_pos;
 	v->rotation_y_pos = v->y_pos;