diff -r fc1723285db9 -r d534f0c8c845 map.h
--- a/map.h	Mon Apr 11 14:59:06 2005 +0000
+++ b/map.h	Mon Apr 11 19:14:48 2005 +0000
@@ -102,10 +102,11 @@
 }
 
 // Functions to calculate distances
-uint DistanceManhattan(TileIndex, TileIndex); // also known as L1-Norm
+uint DistanceManhattan(TileIndex, TileIndex); // also known as L1-Norm. Is the shortest distance one could go over diagonal tracks (or roads)
 uint DistanceSquare(TileIndex, TileIndex); // euclidian- or L2-Norm squared
 uint DistanceMax(TileIndex, TileIndex); // also known as L-Infinity-Norm
 uint DistanceMaxPlusManhattan(TileIndex, TileIndex); // Max + Manhattan
+uint DistanceTrack(TileIndex, TileIndex); // Returns the shortest distance one could go over tracks
 uint DistanceFromEdge(TileIndex); // shortest distance from any edge of the map
 
 
@@ -117,4 +118,10 @@
 	return ToTileIndexDiff(_tileoffs_by_dir[dir]);
 }
 
+/* Approximation of the length of a straight track, relative to a diagonal
+ * track (ie the size of a tile side). #defined instead of const so it can
+ * stay integer. (no runtime float operations) Is this needed?
+ * This value should be sqrt(2)/2 ~ 0.7071 */
+#define STRAIGHT_TRACK_LENGTH (7071/10000)
+
 #endif