diff -r 5e032b540af3 -r 9fc900fbfa79 src/proto2/Terrain.hh
--- a/src/proto2/Terrain.hh	Sun Nov 30 17:13:16 2008 +0000
+++ b/src/proto2/Terrain.hh	Sun Nov 30 17:22:57 2008 +0000
@@ -124,7 +124,7 @@
      * @param point Point for which the normal is calculated.
      * @return Normal vector ((0,0) if there's no terrain)
      */
-    Vector getNormal(Vector point) const;
+    Vector getNormal(Vector point, Vector prevPoint) const;
 
     /**
      * Generate random terrain.