Pack/unpack the tile planes arithmetically.

Instead of a bunch of if statements, add a macro to extract an
individual tile value from the game/goal bitmaps using bitwise
arithmetic, and restructure the drawing paths to use it.

A similar change is made to populate the bitmaps during game board
initialization.  This simplifies the code a bit and also seems to
reduce the compiled size somewhat.

diff --git a/src/curses.c b/src/curses.c
index 5cf88829c07f2225cc8df51c37a3f57df9cec8f0..f66589eab3dac2fac9ae85f993eded99259f375f 100644 (file)
--- a/src/curses.c
+++ b/src/curses.c
@@ -115,17 +115,11 @@ static void draw_tile(WINDOW **win, unsigned colour, unsigned selected,
 
 static int
 redraw_tile(WINDOW **win, unsigned x, unsigned y, unsigned start_column,
-           uint_fast32_t bit0, uint_fast32_t bit1, uint_fast32_t bit2,
-           unsigned selected)
+           uint_least32_t *gp, unsigned selected)
 {
-       uint_fast32_t pos = board_position(x, y);
-       unsigned char tile = 0;
+       unsigned tile = board_tile(gp, 5*y+x);
 
-       if (bit0 & pos) tile |= 1;
-       if (bit1 & pos) tile |= 2;
-       if (bit2 & pos) tile |= 4;
        assert(tile < TILE_MAX);
-
        draw_tile(win, tile, selected, x, y, start_column);
        return tile;
 }
@@ -173,8 +167,7 @@ static void curs_redraw_game(struct app_state *state, uint_fast32_t mask)
        for (i = 0; i < 25; i++) {
                if (mask & 1) {
                        redraw_tile(state->gamewin, i%5, i/5,
-                                   4, gp[0], gp[1], gp[2],
-                                   i == state->cursor);
+                                   4, gp, i == state->cursor);
                }
                mask >>= 1;
        }
@@ -182,7 +175,11 @@ static void curs_redraw_game(struct app_state *state, uint_fast32_t mask)
 
 static void curs_redraw_goal(struct app_state *state, uint_fast32_t mask)
 {
-       uint_least16_t *gp = state->board.goal;
+       uint_least32_t gp[3] = {
+               state->board.goal[0],
+               state->board.goal[1],
+               state->board.goal[2]
+       };
        int i, x, y;
 
        if (!state->goalwin[PLAYWIN_AREA])
@@ -194,8 +191,7 @@ static void curs_redraw_goal(struct app_state *state, uint_fast32_t mask)
 
        for (i = 0; i < 9; i++) {
                if (mask & 1) {
-                       redraw_tile(state->goalwin, i%3, i/3,
-                                   x+2, gp[0], gp[1], gp[2], 0);
+                       redraw_tile(state->goalwin, i%3, i/3, x+2, gp, 0);
                }
                mask >>= 1;
        }

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;
                }
        }
 

diff --git a/src/game.h b/src/game.h
index 7640b415d0bd6aba2c67f98bd3692439f556c43c..e5b9cbed3acffd72dec6bd1ecbdb6b7af090416d 100644 (file)
--- a/src/game.h
+++ b/src/game.h
@@ -167,6 +167,16 @@ 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

diff --git a/src/x11.c b/src/x11.c
index b098d0ea7a43034c3e688ab737389e653b93e788..34f43a9e66de6cd28401ec1019eaaf93a6e96e37 100644 (file)
--- a/src/x11.c
+++ b/src/x11.c
@@ -174,11 +174,9 @@ static void clear_border(struct app_state *state, Display *display, Drawable d,
 
 static int
 redraw_tile(struct app_state *state, Display *display, Drawable d,
-            uint_fast32_t bit0, uint_fast32_t bit1, uint_fast32_t bit2,
-            int x, int y, Dimension w, Dimension h)
+            uint_least32_t *gp, int x, int y, Dimension w, Dimension h)
 {
-       uint_fast32_t pos = board_position(x, y);
-       unsigned char tile = 0;
+       unsigned tile = board_tile(gp, 5*y+x);
 
 #if X11_RENDER_DEBUG
        if (d == XtWindow(state->game) || d == XtWindow(state->goal)) {
@@ -189,12 +187,7 @@ redraw_tile(struct app_state *state, Display *display, Drawable d,
                usleep(70000);
        }
 #endif
-
-       if (bit0 & pos) tile |= 1;
-       if (bit1 & pos) tile |= 2;
-       if (bit2 & pos) tile |= 4;
        assert(tile < TILE_MAX);
-
        if (tile == TILE_EMPTY) {
                XClearArea(display, d, x*w, y*h, w, h, 0);
        } else {
@@ -208,9 +201,13 @@ static int
 redraw_goal_tile(struct app_state *state, Display *display, Drawable d,
                  int x, int y, Dimension w, Dimension h)
 {
-       uint_least16_t *gp = state->board.goal;
+       uint_least32_t gp[3] = {
+               state->board.goal[0],
+               state->board.goal[1],
+               state->board.goal[2]
+       };
 
-       return redraw_tile(state, display, d, gp[0], gp[1], gp[2], x, y, w, h);
+       return redraw_tile(state, display, d, gp, x, y, w, h);
 }
 
 void x11_redraw_goal(struct app_state *state, uint_fast32_t mask)
@@ -226,9 +223,8 @@ void x11_redraw_goal(struct app_state *state, uint_fast32_t mask)
        for (i = 0; i < 9; i++) {
                int x = i%3, y = i/3;
 
-               if (mask & 1) {
+               if (mask & 1)
                        redraw_goal_tile(state, display, goal, x, y, w, h);
-               }
 
                /*
                 * Goal bitmaps have a gap of 2 tiles between each row.
@@ -310,11 +306,8 @@ void x11_redraw_game(struct app_state *state, uint_fast32_t mask)
        }
 
        for (i = 0; i < 25; i++) {
-               if (mask & 1) {
-                       redraw_tile(state, display, game,
-                                   gp[0], gp[1], gp[2],
-                                   i%5, i/5, w, h);
-               }
+               if (mask & 1)
+                       redraw_tile(state, display, game, gp, i%5, i/5, w, h);
                mask >>= 1;
        }
 }