// Marks the path of the laser until it hits a piece or goes off the board.
// Returns the number of unpinned pawns.
//
// p : current board state
// laser_map : end result will be stored here. Every square on the
// path of the laser is marked with mark_mask
// c : color of king shooting laser
// mark_mask: what each square is marked with
int mark_laser_path(position_t *p, char *laser_map, color_t c,
char mark_mask) {
int pinned_pawns = 0;
uint8_t total_pawns;
color_t color = opp_color(c);
square_t o_king_sq = p->kloc[color];
if (c == WHITE) { // opposing king pins our pawns
total_pawns = p->pawn_count[BLACK];
} else {
total_pawns = p->pawn_count[WHITE];
}
// Fire laser, recording in laser_map
square_t sq = p->kloc[c];
int bdir = ori_of(p->board[sq]);
int beam = beam_of(bdir);
tbassert(ptype_of(p->board[sq]) == KING,
"ptype: %d\n", ptype_of(p->board[sq]));
laser_map[sq] |= mark_mask;
// we update h_attackable here
h_attackable = h_dist(sq, o_king_sq);
while (true) {
sq += beam;
laser_map[sq] |= mark_mask;
tbassert(sq < ARR_SIZE && sq >= 0, "sq: %d\n", sq);
switch (ptype_of(p->board[sq])) {
case EMPTY: // empty square
h_attackable += h_dist(sq, o_king_sq);
break;
case PAWN: // Pawn
h_attackable += h_dist(sq, o_king_sq);
if (color_of(p->board[sq]) == color) {
pinned_pawns += 1;
}
bdir = reflect_of(bdir, ori_of(p->board[sq]));
if (bdir < 0) { // Hit back of Pawn
return total_pawns - pinned_pawns;
}
beam = beam_of(bdir);
break;
case KING: // King
h_attackable += h_dist(sq, o_king_sq);
return total_pawns - pinned_pawns;
break;
case INVALID: // Ran off edge of board
return total_pawns - pinned_pawns;
break;
default: // Shouldna happen, man!
tbassert(false, "Not cool, man. Not cool.\n");
break;
}
}
}
// H_SQUARES_ATTACKABLE heuristic: for shooting the enemy king
int h_squares_attackable(position_t *p, color_t c) {
char* laser_map;
if (c == WHITE) {
laser_map = laser_map_white;
} else {
laser_map = laser_map_black;
}
square_t o_king_sq = p->kloc[opp_color(c)];
tbassert(ptype_of(p->board[o_king_sq]) == KING,
"ptype: %d\n", ptype_of(p->board[o_king_sq]));
tbassert(color_of(p->board[o_king_sq]) != c,
"color: %d\n", color_of(p->board[o_king_sq]));
float h_attackable_temp = 0;
for (fil_t f = 0; f < BOARD_WIDTH; f++) {
for (rnk_t r = 0; r < BOARD_WIDTH; r++) {
square_t sq = square_of(f, r);
if (laser_map[sq] != 0) {
h_attackable_temp += h_dist(sq, o_king_sq);
}
}
}
return h_attackable_temp;
}
static long
hamm_dist(register char *p, register char *q)
{
return h_dist(0) + h_dist(1) + h_dist(2) + h_dist(3) + h_dist(4);
}
//#line 36 "../PROTOTYPES/ladders.ch"
long hamm_dist(register char *p, register char *q)
//#line 327 "../ladders.w"
{
return h_dist(0) + h_dist(1) + h_dist(2) + h_dist(3) + h_dist(4);
}