Reduce the amount of redundant drawing in the game area.

[rrace.git] / src / game.h

diff --git a/src/game.h b/src/game.h
index f4473a71ae8d64e332e3bd5690c1f0cc1310ea3c..301dfac022c87681b9be53b88f96bc91dd1b01b0 100644 (file)
--- a/src/game.h
+++ b/src/game.h
@@ -42,11 +42,12 @@ struct board {
         * corresponds to position (0,0), bit 4 is position (4,0) and bit 25
         * is position (4, 4).
         *
-        *   game[0] - the board mask, all bits set except one indicating the
-        *             absense of a tile at this position.
-        *   game[1] - least significant bit of the tile's colour.
-        *   game[2] - tile colour.
-        *   game[3] - most significant bit of the tile's colour.
+        *   game[0] - least significant bit of the tile's colour.
+        *   game[1] - tile colour.
+        *   game[2] - most significant bit of the tile's colour.
+        *   game[3] - No internal meaning.  The game_reset function will clear
+        *             the bit at the empty position and set all others, and
+        *             game_do_move will adjust it.
         */
        uint_least32_t game[4];
 
@@ -110,6 +111,46 @@ static inline uint_fast32_t board_mask_v(int x, int y0, int y1)
        return (col << 5*y1) & (col >> 5*(4-y0));
 }
 
+/*
+ * Return the board bitmap setting locations on or above row y.
+ */
+static inline uint_fast32_t board_above(int y)
+{
+       uint_fast32_t val = board_row(y);
+
+       return val | (val-1);
+}
+
+/*
+ * Return the board bitmap setting locations on or below row y.
+ */
+static inline uint_fast32_t board_below(int y)
+{
+       uint_fast32_t val = board_row(y);
+
+       return val | (~val + 1);
+}
+
+/*
+ * Return the board bitmap setting locations on or left of column x.
+ */
+static inline uint_fast32_t board_left(int x)
+{
+       uint_fast32_t val = board_column(x);
+
+       return val | (val - 0x108421);
+}
+
+/*
+ * Return the board bitmap setting locations on or right of column x.
+ */
+static inline uint_fast32_t board_right(int x)
+{
+       uint_fast32_t val = board_column(x);
+
+       return ~val + 0x108421;
+}
+
 /*
  * Move the bits in the game bitmaps according to a move at position (x, y),
  * and update the location of the empty position which, if the move was valid
@@ -119,6 +160,11 @@ static inline uint_fast32_t board_mask_v(int x, int y0, int y1)
  */
 int game_do_move(struct board *board, int x, int y);
 
+/*
+ * Returns 1 if the game is in a winning position, or 0 otherwise.
+ */
+int game_check_goal(struct board *board);
+
 /*
  * Initialize the game RNG such that the next call to game_reset will produce a
  * new board that is entirely dependent on the given seed value.
@@ -130,4 +176,9 @@ void game_reseed(unsigned long long seed);
  */
 void game_reset(struct board *board);
 
+/*
+ * Disable new moves and clear all tile bits other than the 9 goal tiles.
+ */
+void game_finish(struct board *board);
+
 #endif