Improve game_check_goal implementation slightly.

[rrace.git] / src / game.c

diff --git a/src/game.c b/src/game.c
index 999d52674abd10007334811ec3a8d8562c40d801..47adc9ffe37cb01a90d88647d25246fb2be53332 100644 (file)
--- a/src/game.c
+++ b/src/game.c
@@ -168,6 +168,33 @@ void game_reset(struct board *board)
                        board->y = y;
                }
        }
+
+/* Uncomment to make every game stupidly easy -- winnable in 1 move */
+#if 0
+       /* Force empty space to the border */
+       if (board_position(board->x, board->y) & GOAL_MASK) {
+               switch (rng_uniform_int(4)) {
+               case 0: game_do_move(board, board->x, 0); break;
+               case 1: game_do_move(board, board->x, 4); break;
+               case 2: game_do_move(board, 0, board->y); break;
+               case 3: game_do_move(board, 4, board->y); break;
+               }
+       }
+
+       /* Force goal to match the current board */
+       for (i = 0; i < 3; i++) {
+               board->goal[i] = (board->game[i] & GOAL_MASK) >> GOAL_SHIFT;
+       }
+
+       /* Move empty space back to the centre */
+       if (board->x == 0 || board->x == 4) {
+               game_do_move(board, 1+rng_uniform_int(3), board->y);
+       }
+
+       if (board->y == 0 || board->y == 4) {
+               game_do_move(board, board->x, 1+rng_uniform_int(3));
+       }
+#endif
 }
 
 uint_fast32_t game_do_move(struct board *board, int x, int y)
@@ -209,8 +236,8 @@ uint_fast32_t game_check_goal(struct board *board)
        int i;
 
        for (i = 0; i < 3; i++)
-               mask |= goal[i] ^ (game[i] >> GOAL_SHIFT);
-       return (mask << GOAL_SHIFT) & GOAL_MASK;
+               mask |= game[i] ^ ((0ul+goal[i]) << GOAL_SHIFT);
+       return mask & GOAL_MASK;
 }
 
 void game_begin(struct board *board)
@@ -218,14 +245,14 @@ void game_begin(struct board *board)
        board->time_start = gethrxtime();
 }
 
-static int_fast32_t elapsed(struct board *board)
+int_fast32_t game_elapsed(struct board *board)
 {
        return (gethrxtime() - board->time_start) / 1000000;
 }
 
 int_fast32_t game_finish(struct board *board)
 {
-       int_fast32_t t = elapsed(board);
+       int_fast32_t t = game_elapsed(board);
        int i;
 
        for (i = 0; i < 4; i++) {