(svn r3898) Add functions to find a bridge end starting at a middle tile

bridge_map.h

@@ -15,6 +15,12 @@ static inline bool IsBridgeRamp(TileIndex t)
 	return !HASBIT(_m[t].m5, 6);
 }
 
+static inline bool IsBridgeMiddle(TileIndex t)
+{
+	return HASBIT(_m[t].m5, 6);
+}
+
+
 
 /**
  * Get the direction pointing onto the bridge
@@ -28,6 +34,12 @@ static inline DiagDirection GetBridgeRampDirection(TileIndex t)
 }
 
 
+static inline Axis GetBridgeAxis(TileIndex t)
+{
+	return (Axis)GB(_m[t].m5, 0, 1);
+}
+
+
 static inline bool IsClearUnderBridge(TileIndex t)
 {
 	return GB(_m[t].m5, 3, 3) == 0;
@@ -45,6 +57,17 @@ static inline TransportType GetTransportTypeUnderBridge(TileIndex t)
 }
 
 
+/**
+ * Finds the end of a bridge in the specified direction starting at a middle tile
+ */
+TileIndex GetBridgeEnd(TileIndex, DiagDirection);
+
+/**
+ * Finds the southern end of a bridge starting at a middle tile
+ */
+TileIndex GetSouthernBridgeEnd(TileIndex t);
+
+
 /**
  * Starting at one bridge end finds the other bridge end
  */