X-Git-Url: http://git.draconx.ca/gitweb/rrace.git/blobdiff_plain/a3f2189bfac7e5b1acdf3640cd3b50a7a6636906..a70b0ef8bf7cb26cc779e9b2da480295f5ebf2bd:/src/game.c

diff --git a/src/game.c b/src/game.c
index ca03830..eefafe5 100644
--- a/src/game.c
+++ b/src/game.c
@@ -24,6 +24,7 @@
 #include <limits.h>
 #include <string.h>
 #include <time.h>
+#include <gethrxtime.h>
 #include "game.h"
 
 #define B64(x) ((x) & 0xffffffffffffffff)
@@ -118,13 +119,26 @@ 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];
 	unsigned i;
 
-	if (!rng_is_seeded())
-		game_reseed(time(NULL));
+	if (!rng_is_seeded()) {
+		unsigned long long seed;
+
+		seed = time(NULL);
+		seed += gethrxtime();
+		seed += seed << 32;
+
+		game_reseed(seed);
+	}
 
 	for (i = 0; i < 24; i++) {
 		tiles[i] = (i%6) + 1;
@@ -133,15 +147,13 @@ 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);
-
-		if (tiles[i] & 1)
-			board->goal[0] |= position >> 6;
-		if (tiles[i] & 2)
-			board->goal[1] |= position >> 6;
-		if (tiles[i] & 4)
-			board->goal[2] |= position >> 6;
+	/*
+	 * 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;
@@ -149,33 +161,51 @@ void game_reset(struct board *board)
 	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] = 0x1ffffff ^ 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;
+		}
+	}
+
+/* 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
 }
 
-int game_do_move(struct board *board, int x, int y)
+uint_fast32_t game_do_move(struct board *board, int x, int y)
 {
 	int bx = board->x, by = board->y;
-	uint_least32_t mask, val[4];
+	uint_least32_t ret = 0, mask, val[4];
 	int i, shl, shr;
 
 	if ((bx != x) == (by != y))
-		return -1;
+		return 0;
 
 	if (bx == x) {
 		mask = board_mask_v(x, by, y);
@@ -190,26 +220,40 @@ int game_do_move(struct board *board, int x, int y)
 	for (i = 0; i < 4; i++) {
 		board->game[i] ^= (val[i] = board->game[i] & mask);
 		board->game[i] |= val[i] << shl >> shr;
+		ret |= board->game[i] ^ val[i];
 	}
 
 	board->x = x;
 	board->y = y;
-	return 0;
-}
 
-#define GOAL_MASK 0x739c0
+	return mask & ret;
+}
 
-int game_check_goal(struct board *board)
+uint_fast32_t game_check_goal(struct board *board)
 {
-	int i, ret = 1;
+	uint_least32_t *game = board->game;
+	uint_least16_t *goal = board->goal;
+	uint_least32_t mask = 0;
+	int i;
 
 	for (i = 0; i < 3; i++)
-		ret &= ((board->game[i] & GOAL_MASK) >> 6) == board->goal[i];
-	return ret;
+		mask |= game[i] ^ ((0ul+goal[i]) << GOAL_SHIFT);
+	return mask & GOAL_MASK;
 }
 
-void game_finish(struct board *board)
+void game_begin(struct board *board)
 {
+	board->time_start = gethrxtime();
+}
+
+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 = game_elapsed(board);
 	int i;
 
 	for (i = 0; i < 4; i++) {
@@ -221,4 +265,6 @@ void game_finish(struct board *board)
 	 * disable the game since there will be no valid moves.
 	 */
 	board->x = board->y = -1;
+
+	return t;
 }