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

bridge_map.c

@@ -5,6 +5,26 @@
 #include "bridge_map.h"
 
 
+TileIndex GetBridgeEnd(TileIndex tile, DiagDirection dir)
+{
+	TileIndexDiff delta = TileOffsByDir(dir);
+
+	assert(DiagDirToAxis(dir) == GetBridgeAxis(tile));
+
+	do {
+		tile += delta;
+	} while (!IsBridgeRamp(tile));
+
+	return tile;
+}
+
+
+TileIndex GetSouthernBridgeEnd(TileIndex t)
+{
+	return GetBridgeEnd(t, AxisToDiagDir(GetBridgeAxis(t)));
+}
+
+
 TileIndex GetOtherBridgeEnd(TileIndex tile)
 {
 	TileIndexDiff delta = TileOffsByDir(GetBridgeRampDirection(tile));