From: Carl Worth <cworth@cworth.org>
Date: Thu, 5 Mar 2009 18:03:13 +0000 (-0800)
Subject: Eliminate stacks disconnected from red DVONN pieces
X-Git-Url: https://git.cworth.org/git?p=dvonn;a=commitdiff_plain;h=290d2396610f08c48eda9fd2400679176448d7d9

Eliminate stacks disconnected from red DVONN pieces

At this point, the game is actually playable for the first time.
There's still very little actual UI here, (no indication of who
the current player is, no buttons for passing, starting a new
game, etc.). But with two people who know how to right-click
and have out-of-band communication to say when its the
opponent's turn, it's possible to play now.
---

diff --git a/dvonn-board.c b/dvonn-board.c
index 4aaac54..5b7c106 100644
--- a/dvonn-board.c
+++ b/dvonn-board.c
@@ -239,6 +239,49 @@ dvonn_board_place (dvonn_board_t *board,
     return TRUE;
 }
 
+static void
+fill_living(dvonn_board_t *board,
+	    int living[DVONN_BOARD_X_SIZE][DVONN_BOARD_Y_SIZE],
+	    int x, int y)
+{
+    if (dvonn_board_cell_occupied (board, x, y) && ! living[x][y])
+    {
+	living[x][y] = 1;
+
+	fill_living (board, living, x - 1, y);
+	fill_living (board, living, x + 1, y);
+	fill_living (board, living, x, y - 1);
+	fill_living (board, living, x, y + 1);
+	fill_living (board, living, x + 1, y - 1);
+	fill_living (board, living, x - 1, y + 1);
+    }
+}
+
+static void
+eliminate_disconnected_stacks (dvonn_board_t *board)
+{
+    int x, y;
+    int living[DVONN_BOARD_X_SIZE][DVONN_BOARD_Y_SIZE];
+
+    for (x = 0; x < DVONN_BOARD_X_SIZE; x++)
+	for (y = 0; y < DVONN_BOARD_Y_SIZE; y++)
+	    living[x][y] = 0;
+
+    for (x = 0; x < DVONN_BOARD_X_SIZE; x++)
+	for (y = 0; y < DVONN_BOARD_Y_SIZE; y++)
+	    if (board->cells[x][y].contains_red)
+		fill_living (board, living, x, y);
+
+    for (x = 0; x < DVONN_BOARD_X_SIZE; x++)
+	for (y = 0; y < DVONN_BOARD_Y_SIZE; y++)
+	    if (dvonn_board_cell_occupied (board, x, y) &&
+		! living[x][y])
+	    {
+		board->cells[x][y].type = DVONN_CELL_EMPTY;
+		board->cells[x][y].height = 0;
+	    }
+}
+
 int
 dvonn_board_move (dvonn_board_t *board,
 		  int x1, int y1,
@@ -261,6 +304,8 @@ dvonn_board_move (dvonn_board_t *board,
     board->cells[x1][y1].height = 0;
     board->cells[x1][y1].contains_red = FALSE;
 
+    eliminate_disconnected_stacks (board);
+
     dvonn_board_next_player (board);
 
     return TRUE;