cgol

commit 532da220dbb29fb0d09cdce2473634074c487812
parent d0b08002961ba6d30a87003747cbc56f70161908
Author: aabacchus <ben@bvnf.space>
Date:   Tue, 28 Sep 2021 12:19:24 +0100

make the board wrap around like a torus

Diffstat:
M
rules.c
 | 
22
++++++++--------------

1 file changed, 8 insertions(+), 14 deletions(-)
diff --git a/rules.c b/rules.c
@@ -40,8 +40,14 @@ evolve(short *cells, int nx, int ny) {
 
 int
 alive(int x, int y, short *cells, int nx, int ny) {
-    if (y < 0 || y >= ny || x < 0 || x >= nx)
-        return WHATS_OUTSIDE;
+    if (y < 0)
+        y += ny;
+    else if (y >= ny)
+        y -= ny;
+    if (x < 0)
+        x += nx;
+    else if (x >= nx)
+        x -= nx;
     return (int) *(cells + y * nx + x);
 }
 
@@ -50,19 +56,7 @@ neighbours(int x, int y, short *cells, int nx, int ny) {
     int n = 0;
     int x0, y0;
     for (y0 = y - 1; y0 <= y + 1; y0++) {
-        /*
-        if (y0 < 0 || y0 >= ny) {
-            n += WHATS_OUTSIDE;
-            continue;
-        }
-        */
         for (x0 = x - 1; x0 <= x + 1; x0++) {
-            /*
-            if (x0 < 0 || x0 >= nx) {
-                n += WHATS_OUTSIDE;
-                continue;
-            }
-            */
             if (alive(x0, y0, cells, nx, ny))
                 n++;
         }