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-rw-r--r--src/tunnel_map.c50
1 files changed, 50 insertions, 0 deletions
diff --git a/src/tunnel_map.c b/src/tunnel_map.c
new file mode 100644
index 000000000..a4945591d
--- /dev/null
+++ b/src/tunnel_map.c
@@ -0,0 +1,50 @@
+/* $Id$ */
+
+#include "stdafx.h"
+#include "openttd.h"
+#include "tile.h"
+#include "tunnel_map.h"
+
+TileIndex GetOtherTunnelEnd(TileIndex tile)
+{
+ DiagDirection dir = GetTunnelDirection(tile);
+ TileIndexDiff delta = TileOffsByDiagDir(dir);
+ uint z = GetTileZ(tile);
+
+ dir = ReverseDiagDir(dir);
+ do {
+ tile += delta;
+ } while (
+ !IsTunnelTile(tile) ||
+ GetTunnelDirection(tile) != dir ||
+ GetTileZ(tile) != z
+ );
+
+ return tile;
+}
+
+
+static bool IsTunnelInWayDir(TileIndex tile, uint z, DiagDirection dir)
+{
+ TileIndexDiff delta = TileOffsByDiagDir(dir);
+ uint height;
+
+ do {
+ tile -= delta;
+ height = GetTileZ(tile);
+ } while (z < height);
+
+ return
+ z == height &&
+ IsTunnelTile(tile) &&
+ GetTunnelDirection(tile) == dir;
+}
+
+bool IsTunnelInWay(TileIndex tile, uint z)
+{
+ return
+ IsTunnelInWayDir(tile, z, DIAGDIR_NE) ||
+ IsTunnelInWayDir(tile, z, DIAGDIR_SE) ||
+ IsTunnelInWayDir(tile, z, DIAGDIR_SW) ||
+ IsTunnelInWayDir(tile, z, DIAGDIR_NW);
+}