X-Git-Url: https://git.draconx.ca/gitweb/rrace.git/blobdiff_plain/a3f2189bfac7e5b1acdf3640cd3b50a7a6636906..ca97af514870895e228df0443adc5a16be4d9a78:/src/game.h

diff --git a/src/game.h b/src/game.h
index d17eb99..efa7ef0 100644
--- a/src/game.h
+++ b/src/game.h
@@ -20,6 +20,7 @@
 #define RRACE_GAME_H_
 
 #include <inttypes.h>
+#include <xtime.h>
 
 enum {
 	TILE_EMPTY,
@@ -32,7 +33,10 @@ enum {
 	TILE_MAX
 };
 
-enum { GOAL_SHIFT = 6 };
+#define GOAL_SHIFT 6
+#define GOAL_MASK 0x739c0ul
+#define GAME_MASK 0x1fffffful
+
 struct board {
 	/*
 	 * Bit planes representing the current game area.
@@ -45,8 +49,9 @@ struct board {
 	 *   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] - the board mask, all bits set except one indicating the
-	 *             absense of a tile at this position.
+	 *   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];
 
@@ -62,8 +67,10 @@ struct board {
 	 */
 	uint_least16_t goal[3];
 
-	/* (x, y) position of the current empty position. */
+	/* (x, y) position of the current empty space. */
 	uint_least8_t x, y;
+
+	xtime_t time_start;
 };
 
 /* Return the board bitmap with all bits in column x set */
@@ -110,19 +117,82 @@ 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)
+{
+	return ( 0x20ul << 5*y ) - 1;
+}
+
+/*
+ * Return the board bitmap setting locations on or below row y.
+ */
+static inline uint_fast32_t board_below(int y)
+{
+	return ~( 1ul << 5*y ) + 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;
+}
+
+/*
+ * Return the board bitmap setting the rectangle of locations that are:
+ *
+ *   - on or right of column x1, and
+ *   - on or left of column x2, and
+ *   - on or below row y1, and
+ *   - on or above row y2.
+ *
+ * It must be the case that x2 >= x1 and y2 >= y1.
+ */
+static inline uint_fast32_t board_rect(int x1, int y1, int x2, int y2)
+{
+	return (board_left(x2-x1) << x1) & (board_above(y2-y1) << 5*y1);
+}
+
+/*
+ * Extract the tile colour from a specific position of one of the
+ * arrays of tile bitmaps.  The position is a bit index.  So for
+ * example, game the tile at a given (x, y) position can be extracted
+ * by board_tile(board.game, 5*y+x).
+ */
+#define board_tile(planes, bit) (((0[planes]<<0) >> (bit)) & 1) \
+                              | (((1[planes]<<1) >> (bit)) & 2) \
+                              | (((2[planes]<<2) >> (bit)) & 4)
+
 /*
  * 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
  * is now (x, y).
  *
- * Returns 0 if the move was valid (and board has been updated), -1 otherwise.
+ * Returns the board bitmap indicating which positions changed.  A return
+ * value of 0 therefore indicates an invalid move.
  */
-int game_do_move(struct board *board, int x, int y);
+uint_fast32_t game_do_move(struct board *board, int x, int y);
 
 /*
- * Returns 1 if the game is in a winning position, or 0 otherwise.
+ * Returns the board bitmap setting game locations that differ from the goal.
+ * A return value of 0 therefore indicates a winning position.
  */
-int game_check_goal(struct board *board);
+uint_fast32_t game_check_goal(struct board *board);
 
 /*
  * Initialize the game RNG such that the next call to game_reset will produce a
@@ -135,9 +205,20 @@ void game_reseed(unsigned long long seed);
  */
 void game_reset(struct board *board);
 
+/*
+ * Reset the game start time.
+ */
+void game_begin(struct board *board);
+
+/*
+ * Return the total elapsed time (in ms) since the last call to game_begin.
+ */
+int_fast32_t game_elapsed(struct board *board);
+
 /*
  * Disable new moves and clear all tile bits other than the 9 goal tiles.
+ * Returns the total elapsed time (in ms).
  */
-void game_finish(struct board *board);
+int_fast32_t game_finish(struct board *board);
 
 #endif