From 67c046e4471ea322cc8ec91b680e222e74bc1f71 Mon Sep 17 00:00:00 2001
From: P. J. McDermott <pjm@nac.net>
Date: Tue, 13 Dec 2011 02:28:10 -0500
Subject: Fix tick corruption that resulted in strangeness.

---
diff --git a/src/cgol.c b/src/cgol.c
index 8ef6404..6add490 100644
--- a/src/cgol.c
+++ b/src/cgol.c
@@ -33,7 +33,7 @@ void tick();
 int count_live_neighbors(int i, int j);
 bool get_cell(int i, int j);
 void set_cell(int i, int j, bool s);
-void print_cell(int i, int j);
+void print_cell(int i, int j, bool next);
 void usage(const char *invocation);
 
 static int width, height;
@@ -145,16 +145,18 @@ init_game()
 		if (r > seedprob) {
 			/* Dead. */
 			grid_cur[i] = false;
+			grid_next[i] = false;
 		} else {
 			/* Alive. */
 			grid_cur[i] = true;
+			grid_next[i] = true;
 		}
 	}
 
 	/* Print the grid. */
 	for (i = 0; i < height; ++i) {
 		for (j = 0; j < width; ++j) {
-			print_cell(i, j);
+			print_cell(i, j, false);
 		}
 	}
 }
@@ -181,24 +183,23 @@ tick()
 	for (i = 0; i < height; ++i) {
 		for (j = 0; j < width; ++j) {
 			n = count_live_neighbors(i, j);
-			if (get_cell(i, j)) {
+			if (get_cell(i, j) == true) {
 				if (n < 2 || n > 3) {
 					set_cell(i, j, false);
-					print_cell(i, j);
+					print_cell(i, j, true);
 				}
 			} else {
 				if (n == 3) {
 					set_cell(i, j, true);
-					print_cell(i, j);
+					print_cell(i, j, true);
 				}
 			}
 		}
 	}
 
-	/* Swap grids. */
-	grid_tmp = grid_cur;
-	grid_cur = grid_next;
-	grid_next = grid_tmp;
+	memcpy(grid_cur, grid_next, sizeof(bool) * width * height);
+
+	refresh();
 }
 
 int
@@ -226,13 +227,17 @@ get_cell(int i, int j)
 void
 set_cell(int i, int j, bool s)
 {
-	grid_cur[i * width + j] = s;
+	grid_next[i * width + j] = s;
 }
 
 void
-print_cell(int i, int j)
+print_cell(int i, int j, bool next)
 {
-	mvprintw(1 + i, 1 + j * 2, "%c", grid_cur[i * width + j] ? 'o' : ' ');
+	if (next) {
+		mvprintw(1 + i, 1 + j * 2, "%c", grid_next[i * width + j] ? 'o' : ' ');
+	} else {
+		mvprintw(1 + i, 1 + j * 2, "%c", grid_cur[i * width + j] ? 'o' : ' ');
+	}
 }
 
 void
--
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