Pack/unpack the tile planes arithmetically.

[rrace.git] / src / game.c

diff --git a/src/game.c b/src/game.c
index 47adc9ffe37cb01a90d88647d25246fb2be53332..eefafe5ac40e16d93df0581a51fc23a46539202b 100644 (file)
--- a/src/game.c
+++ b/src/game.c
@@ -119,6 +119,12 @@ void game_reseed(unsigned long long seed)
        rng_state[3] = splitmix64(&seed);
 }
 
+#define assign_tile(planes, tile, bit) do { \
+       0[planes] |= (((tile)>>0) & 1ul) << (bit); \
+       1[planes] |= (((tile)>>1) & 1ul) << (bit); \
+       2[planes] |= (((tile)>>2) & 1ul) << (bit); \
+} while (0)
+
 void game_reset(struct board *board)
 {
        unsigned char tiles[25];
@@ -141,31 +147,26 @@ void game_reset(struct board *board)
        shuffle(tiles, 24);
        memset(board->goal, 0, sizeof board->goal);
 
-       for (i = 0; i < 9; i++) {
-               uint_fast32_t position = board_position(i/3+1, i%3+1) >> 6;
-
-               if (tiles[i] & 1) board->goal[0] |= position;
-               if (tiles[i] & 2) board->goal[1] |= position;
-               if (tiles[i] & 4) board->goal[2] |= position;
+       /*
+        * Goal bitmap has 2-tile "gaps" between rows; it doesn't matter what
+        * these are set to and since we have a random permutation it doesn't
+        * matter which of the 24 nonempty tiles we pick for the actual goal.
+        */
+       for (i = 0; i < 13; i++) {
+               assign_tile(board->goal, tiles[i], i);
        }
 
        tiles[24] = TILE_EMPTY;
        shuffle(tiles, 25);
-
        memset(board->game, 0, sizeof board->game);
+
        for (i = 0; i < 25; i++) {
-               unsigned x = i/5, y = i%5;
-               uint_fast32_t position;
-
-               position = board_position(x, y);
-               if (tiles[i] != TILE_EMPTY) {
-                       if (tiles[i] & 1) board->game[0] |= position;
-                       if (tiles[i] & 2) board->game[1] |= position;
-                       if (tiles[i] & 4) board->game[2] |= position;
-               } else {
-                       board->game[3] = ~position;
-                       board->x = x;
-                       board->y = y;
+               assign_tile(board->game, tiles[i], i);
+
+               if (tiles[i] == TILE_EMPTY) {
+                       board->game[3] = (1ul<<i);
+                       board->x = i%5;
+                       board->y = i/5;
                }
        }