From: Nick Bowler <nbowler@draconx.ca>
Date: Wed, 9 Mar 2022 02:07:48 +0000 (-0500)
Subject: Very slightly simplify game_reset implementation.
X-Git-Url: http://git.draconx.ca/gitweb/rrace.git/commitdiff_plain/a13b072946d80c2da325e90cb73d96a25485a80a

Very slightly simplify game_reset implementation.
---

diff --git a/src/game.c b/src/game.c
index ca03830..bdb18a1 100644
--- a/src/game.c
+++ b/src/game.c
@@ -134,34 +134,28 @@ void game_reset(struct board *board)
 	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;
+		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;
 	}
 
 	tiles[24] = TILE_EMPTY;
 	shuffle(tiles, 25);
-	memset(board->game, 0, sizeof board->game);
 
+	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;
+			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->game[3] = ~position;
 			board->x = x;
 			board->y = y;
 		}
diff --git a/src/game.h b/src/game.h
index d17eb99..fb2fe97 100644
--- a/src/game.h
+++ b/src/game.h
@@ -45,8 +45,9 @@ 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];