(svn r27157) -Fix: Mark bridge middle tiles dirty when building/removing/changing bridges.

src/rail_cmd.cpp

@@ -1688,13 +1688,11 @@ CommandCost CmdConvertRail(TileIndex tile, DoCommandFlag flags, uint32 p1, uint3
 					YapfNotifyTrackLayoutChange(tile, track);
 					YapfNotifyTrackLayoutChange(endtile, track);
 
-					MarkTileDirtyByTile(tile);
-					MarkTileDirtyByTile(endtile);
-
 					if (IsBridge(tile)) {
-						TileIndexDiff delta = TileOffsByDiagDir(GetTunnelBridgeDirection(tile));
-						TileIndex t = tile + delta;
-						for (; t != endtile; t += delta) MarkTileDirtyByTile(t); // TODO encapsulate this into a function
+						MarkBridgeDirty(tile);
+					} else {
+						MarkTileDirtyByTile(tile);
+						MarkTileDirtyByTile(endtile);
 					}
 				}
 

src/road_cmd.cpp

@@ -246,12 +246,11 @@ static CommandCost RemoveRoad(TileIndex tile, DoCommandFlag flags, RoadBits piec
 				}
 
 				/* Mark tiles dirty that have been repaved */
-				MarkTileDirtyByTile(tile);
-				MarkTileDirtyByTile(other_end);
 				if (IsBridge(tile)) {
-					TileIndexDiff delta = TileOffsByDiagDir(GetTunnelBridgeDirection(tile));
-
-					for (TileIndex t = tile + delta; t != other_end; t += delta) MarkTileDirtyByTile(t);
+					MarkBridgeDirty(tile);
+				} else {
+					MarkTileDirtyByTile(tile);
+					MarkTileDirtyByTile(other_end);
 				}
 			}
 		} else {
@@ -747,12 +746,11 @@ do_clear:;
 				SetRoadOwner(tile, rt, company);
 
 				/* Mark tiles dirty that have been repaved */
-				MarkTileDirtyByTile(other_end);
-				MarkTileDirtyByTile(tile);
 				if (IsBridge(tile)) {
-					TileIndexDiff delta = TileOffsByDiagDir(GetTunnelBridgeDirection(tile));
-
-					for (TileIndex t = tile + delta; t != other_end; t += delta) MarkTileDirtyByTile(t);
+					MarkBridgeDirty(tile);
+				} else {
+					MarkTileDirtyByTile(other_end);
+					MarkTileDirtyByTile(tile);
 				}
 				break;
 			}

src/tunnelbridge.h

@@ -14,6 +14,9 @@
 
 #include "map_func.h"
 
+void MarkBridgeDirty(TileIndex begin, TileIndex end, DiagDirection direction, uint bridge_height);
+void MarkBridgeDirty(TileIndex tile);
+
 /**
  * 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

@@ -52,6 +52,33 @@ TileIndex _build_tunnel_endtile; ///< The end of a tunnel; as hidden return from
 /** Z position of the bridge sprites relative to bridge height (downwards) */
 static const int BRIDGE_Z_START = 3;
 
+
+/**
+ * Mark bridge tiles dirty.
+ * Note: The bridge does not need to exist, everything is passed via parameters.
+ * @param begin Start tile.
+ * @param end End tile.
+ * @param direction Direction from \a begin to \a end.
+ * @param bridge_height Bridge height level.
+ */
+void MarkBridgeDirty(TileIndex begin, TileIndex end, DiagDirection direction, uint bridge_height)
+{
+	TileIndexDiff delta = TileOffsByDiagDir(direction);
+	for (TileIndex t = begin; t != end; t += delta) {
+		MarkTileDirtyByTile(t, bridge_height - TileHeight(t));
+	}
+	MarkTileDirtyByTile(end);
+}
+
+/**
+ * Mark bridge tiles dirty.
+ * @param tile Bridge head.
+ */
+void MarkBridgeDirty(TileIndex tile)
+{
+	MarkBridgeDirty(tile, GetOtherTunnelBridgeEnd(tile), GetTunnelBridgeDirection(tile), GetBridgeHeight(tile));
+}
+
 /** Reset the data been eventually changed by the grf loaded. */
 void ResetBridges()
 {
@@ -506,10 +533,7 @@ CommandCost CmdBuildBridge(TileIndex end_tile, DoCommandFlag flags, uint32 p1, u
 		}
 
 		/* Mark all tiles dirty */
-		TileIndexDiff delta = (direction == AXIS_X ? TileDiffXY(1, 0) : TileDiffXY(0, 1));
-		for (TileIndex tile = tile_start; tile <= tile_end; tile += delta) {
-			MarkTileDirtyByTile(tile);
-		}
+		MarkBridgeDirty(tile_start, tile_end, AxisToDiagDir(direction), z_start);
 		DirtyCompanyInfrastructureWindows(owner);
 	}
 
@@ -926,7 +950,7 @@ static CommandCost DoClearBridge(TileIndex tile, DoCommandFlag flags)
 				if (height < minz) SetRoadside(c, ROADSIDE_PAVED);
 			}
 			ClearBridgeMiddle(c);
-			MarkTileDirtyByTile(c);
+			MarkTileDirtyByTile(c, height - TileHeight(c));
 		}
 
 		if (rail) {

src/viewport.cpp

@@ -2232,14 +2232,15 @@ void ConstrainAllViewportsZoom()
 /**
  * Mark a tile given by its index dirty for repaint.
  * @param tile The tile to mark dirty.
+ * @param bridge_level_offset Height of bridge on tile to also mark dirty. (Height level relative to north corner.)
  * @ingroup dirty
  */
-void MarkTileDirtyByTile(TileIndex tile)
+void MarkTileDirtyByTile(TileIndex tile, int bridge_level_offset)
 {
 	Point pt = RemapCoords(TileX(tile) * TILE_SIZE, TileY(tile) * TILE_SIZE, TilePixelHeight(tile));
 	MarkAllViewportsDirty(
 			pt.x - MAX_TILE_EXTENT_LEFT,
-			pt.y - MAX_TILE_EXTENT_TOP,
+			pt.y - MAX_TILE_EXTENT_TOP - ZOOM_LVL_BASE * TILE_HEIGHT * bridge_level_offset,
 			pt.x + MAX_TILE_EXTENT_RIGHT,
 			pt.y + MAX_TILE_EXTENT_BOTTOM);
 }

src/viewport_func.h

@@ -77,7 +77,7 @@ void UpdateAllVirtCoords();
 
 extern Point _tile_fract_coords;
 
-void MarkTileDirtyByTile(TileIndex tile);
+void MarkTileDirtyByTile(TileIndex tile, int bridge_level_offset = 0);
 
 int GetRowAtTile(int viewport_y, Point tile, bool bridge_correct);
 void MarkTileDirtyByTileOutsideMap(int x, int y);