+void Terrain::Tile::set_node_elevation(unsigned i, float e)
+{
+ nodes[i].elevation = e;
+ update_axis();
+}
+
+void Terrain::Tile::update_axis()
+{
+ secondary_axis = (abs(nodes[1].elevation-nodes[2].elevation) < abs(nodes[0].elevation-nodes[3].elevation));
+}
+