Reduce screen re-draw area for tunnel/bridge end signal updates

src/rail.h

@@ -478,6 +478,7 @@ static inline Money SignalMaintenanceCost(uint32 num)
 }
 
 void MarkSingleSignalDirty(TileIndex tile, Trackdir td);
+void MarkSingleSignalDirtyAtZ(TileIndex tile, Trackdir td, uint z);
 
 void DrawTrainDepotSprite(int x, int y, int image, RailType railtype);
 int TicksToLeaveDepot(const Train *v);

src/rail_cmd.cpp

@@ -2766,13 +2766,9 @@ static void DrawSingleSignal(TileIndex tile, const RailtypeInfo *rti, Track trac
 	DrawSingleSignal(tile, rti, track, condition, image, pos, type, variant, show_restricted);
 }
 
-void MarkSingleSignalDirty(TileIndex tile, Trackdir td)
+template <typename F>
+void MarkSingleSignalDirtyIntl(TileIndex tile, Trackdir td, F get_z)
 {
-	if (_signal_sprite_oversized || td >= TRACKDIR_END) {
-		MarkTileDirtyByTile(tile, VMDF_NOT_MAP_MODE);
-		return;
-	}
-
 	static const uint8 trackdir_to_pos[TRACKDIR_END] = {
 		8,  // TRACKDIR_X_NE
 		10, // TRACKDIR_Y_SE
@@ -2794,7 +2790,7 @@ void MarkSingleSignalDirty(TileIndex tile, Trackdir td)
 
 	uint x, y;
 	GetSignalXY(tile, trackdir_to_pos[td], x, y);
-	Point pt = RemapCoords(x, y, GetSaveSlopeZ(x, y, TrackdirToTrack(td)));
+	Point pt = RemapCoords(x, y, get_z(x, y));
 	MarkAllViewportsDirty(
 			pt.x - SIGNAL_DIRTY_LEFT,
 			pt.y - SIGNAL_DIRTY_TOP,
@@ -2804,6 +2800,25 @@ void MarkSingleSignalDirty(TileIndex tile, Trackdir td)
 	);
 }
 
+void MarkSingleSignalDirty(TileIndex tile, Trackdir td)
+{
+	if (_signal_sprite_oversized || td >= TRACKDIR_END) {
+		MarkTileDirtyByTile(tile, VMDF_NOT_MAP_MODE);
+		return;
+	}
+
+	MarkSingleSignalDirtyIntl(tile, td, [td](uint x, uint y) -> uint {
+		return GetSaveSlopeZ(x, y, TrackdirToTrack(td));
+	});
+}
+
+void MarkSingleSignalDirtyAtZ(TileIndex tile, Trackdir td, uint z)
+{
+	MarkSingleSignalDirtyIntl(tile, td, [z](uint x, uint y) -> uint {
+		return z;
+	});
+}
+
 static uint32 _drawtile_track_palette;
 
 

src/signal.cpp

@@ -720,7 +720,7 @@ static void UpdateSignalsAroundSegment(SigInfo info)
 					uint8 aspect = GetForwardAspectAndIncrement(info, tile, exit_td);
 					if (aspect != GetTunnelBridgeExitSignalAspect(tile)) {
 						SetTunnelBridgeExitSignalAspect(tile, aspect);
-						MarkTileDirtyByTile(tile, VMDF_NOT_MAP_MODE);
+						MarkTunnelBridgeSignalDirty(tile, true);
 						PropagateAspectChange(tile, exit_td, aspect);
 					}
 				}
@@ -748,7 +748,7 @@ static void UpdateSignalsAroundSegment(SigInfo info)
 					PropagateAspectChange(tile, exit_td, aspect);
 				}
 			}
-			if (refresh) MarkTileDirtyByTile(tile, VMDF_NOT_MAP_MODE);
+			if (refresh) MarkTunnelBridgeSignalDirty(tile, true);
 
 			continue;
 		}
@@ -857,7 +857,7 @@ static void UpdateSignalsAroundSegment(SigInfo info)
 			uint8 old_aspect = GetTunnelBridgeExitSignalAspect(tile);
 			if (aspect != old_aspect) {
 				SetTunnelBridgeExitSignalAspect(tile, aspect);
-				if (old_aspect != 0) MarkTileDirtyByTile(tile, VMDF_NOT_MAP_MODE);
+				if (old_aspect != 0) MarkTunnelBridgeSignalDirty(tile, true);
 				PropagateAspectChange(tile, trackdir, aspect);
 			}
 		} else {
@@ -1358,7 +1358,7 @@ void PropagateAspectChange(TileIndex tile, Trackdir trackdir, uint8 aspect)
 						if (!IsTunnelBridgeSignalSimulationExit(tile) || GetTunnelBridgeExitSignalState(tile) != SIGNAL_STATE_GREEN) return;
 						if (GetTunnelBridgeExitSignalAspect(tile) == aspect) return;
 						SetTunnelBridgeExitSignalAspect(tile, aspect);
-						MarkTileDirtyByTile(tile, VMDF_NOT_MAP_MODE);
+						MarkTunnelBridgeSignalDirty(tile, true);
 						if (IsBridge(tile)) RefreshBridgeOnExitAspectChange(other, tile);
 						aspect = std::min<uint>(GetSignalledTunnelBridgeEntranceForwardAspect(other, tile) + 1, _extra_aspects + 1);
 					}
@@ -1372,7 +1372,7 @@ void PropagateAspectChange(TileIndex tile, Trackdir trackdir, uint8 aspect)
 							if (!IsTunnelBridgeSignalSimulationEntrance(tile) || GetTunnelBridgeEntranceSignalState(tile) != SIGNAL_STATE_GREEN) return;
 							if (GetTunnelBridgeEntranceSignalAspect(tile) == aspect) return;
 							SetTunnelBridgeEntranceSignalAspect(tile, aspect);
-							MarkTileDirtyByTile(tile, VMDF_NOT_MAP_MODE);
+							MarkTunnelBridgeSignalDirty(tile, false);
 							aspect = std::min<uint>(aspect + 1, _extra_aspects + 1);
 						}
 					}

src/train_cmd.cpp

@@ -3365,7 +3365,7 @@ static void UpdateTunnelBridgeEntranceSignalAspect(TileIndex tile)
 	uint8 old_aspect = GetTunnelBridgeEntranceSignalAspect(tile);
 	if (aspect != old_aspect) {
 		SetTunnelBridgeEntranceSignalAspect(tile, aspect);
-		MarkTileDirtyByTile(tile, VMDF_NOT_MAP_MODE);
+		MarkTunnelBridgeSignalDirty(tile, false);
 		PropagateAspectChange(tile, trackdir, aspect);
 	}
 }
@@ -3374,7 +3374,7 @@ static void SetTunnelBridgeEntranceSignalGreen(TileIndex tile)
 {
 	if (GetTunnelBridgeEntranceSignalState(tile) == SIGNAL_STATE_RED) {
 		SetTunnelBridgeEntranceSignalState(tile, SIGNAL_STATE_GREEN);
-		MarkTileDirtyByTile(tile, VMDF_NOT_MAP_MODE);
+		MarkTunnelBridgeSignalDirty(tile, false);
 		if (_extra_aspects > 0) {
 			SetTunnelBridgeEntranceSignalAspect(tile, 0);
 			UpdateAspectDeferred(tile, GetTunnelBridgeEntranceTrackdir(tile));

src/tunnelbridge.h

@@ -17,6 +17,8 @@ uint GetTunnelBridgeSignalSimulationSpacingTarget(Owner owner);
 uint GetBestTunnelBridgeSignalSimulationSpacing(Owner owner, TileIndex begin, TileIndex end);
 uint GetTunnelBridgeSignalSimulationSignalCount(TileIndex begin, TileIndex end);
 
+void MarkTunnelBridgeSignalDirty(TileIndex tile, bool exit);
+
 /**
  * Calculates the length of a tunnel or a bridge (without end tiles)
  * @param begin The begin of the tunnel or bridge.

src/tunnelbridge_cmd.cpp

@@ -1894,6 +1894,65 @@ void MarkSingleBridgeSignalDirty(TileIndex tile, TileIndex bridge_start_tile)
 	);
 }
 
+void MarkTunnelBridgeSignalDirty(TileIndex tile, bool exit)
+{
+	if (_signal_sprite_oversized) {
+		MarkTileDirtyByTile(tile, VMDF_NOT_MAP_MODE);
+		return;
+	}
+
+	if (IsRailCustomBridgeHeadTile(tile)) {
+		Trackdir td = exit ? GetTunnelBridgeExitTrackdir(tile) : GetTunnelBridgeEntranceTrackdir(tile);
+		MarkSingleSignalDirtyAtZ(tile, td, GetTileMaxPixelZ(tile));
+		return;
+	}
+
+	bool side = (_settings_game.vehicle.road_side != 0) && _settings_game.construction.train_signal_side;
+	DiagDirection dir = GetTunnelBridgeDirection(tile);
+
+	uint position;
+	switch (dir) {
+		default: NOT_REACHED();
+		case DIAGDIR_NE: position = 0; break;
+		case DIAGDIR_SE: position = 2; break;
+		case DIAGDIR_SW: position = 1; break;
+		case DIAGDIR_NW: position = 3; break;
+	}
+
+	static const Point SignalPositions[2][4] = {
+		{   /*  X         X         Y         Y     Signals on the left side */
+			{13,  3}, { 2, 13}, { 3,  4}, {13, 14}
+		}, {/*  X         X         Y         Y     Signals on the right side */
+			{14, 13}, { 3,  3}, {13,  2}, { 3, 13}
+		}
+	};
+
+	uint x = TileX(tile) * TILE_SIZE + SignalPositions[side != exit][position].x;
+	uint y = TileY(tile) * TILE_SIZE + SignalPositions[side != exit][position].y;
+
+	int z;
+	if (IsTunnel(tile)) {
+		z = GetTileZ(tile) * TILE_HEIGHT;
+	} else {
+		Slope slope = GetTilePixelSlope(tile, &z);
+		if (slope == SLOPE_FLAT) {
+			if (side == exit && dir == DIAGDIR_SE) z += 2;
+			if (side != exit && dir == DIAGDIR_SW) z += 2;
+		} else {
+			z += 8;
+		}
+	}
+
+	Point pt = RemapCoords(x, y, z);
+	MarkAllViewportsDirty(
+			pt.x - SIGNAL_DIRTY_LEFT,
+			pt.y - SIGNAL_DIRTY_TOP,
+			pt.x + SIGNAL_DIRTY_RIGHT,
+			pt.y + SIGNAL_DIRTY_BOTTOM,
+			VMDF_NOT_MAP_MODE
+	);
+}
+
 /**
  * Draws a tunnel of bridge tile.
  * For tunnels, this is rather simple, as you only need to draw the entrance.