/* $Id$ */
/* Rail selection types (directions):
/ \ / \ / \ / \ / \ / \
/ /\ /\ \ /===\ / \ /| \ / |\
\/ / \ \/ \ / \===/ \| / \ |/
\ / \ / \ / \ / \ / \ /
0 1 2 3 4 5
*/
// mark invalid tiles red
#define RED(c) c | PALETTE_SEL_TILE_RED
// table maps each of the six rail directions and tileh combinations to a sprite