cgol

commit 54b8cd8fce22623c4063c3ac7df092825f99aa22
parent 7bcbc09e0f12589af69eafbdc39fa74bf9d0e1ac
Author: aabacchus <ben@bvnf.space>
Date:   Tue, 28 Sep 2021 11:58:32 +0100

add some command line options

Diffstat:
M
Makefile
 | 
2
+-
M
cgol.1
 | 
11
++++++++++-
M
main.c
 | 
76
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++----------------

3 files changed, 71 insertions(+), 18 deletions(-)
diff --git a/Makefile b/Makefile
@@ -25,7 +25,7 @@ images:
 	mkdir -p images
 
 out.webm: images
-	ffmpeg -r 15 -i images/%04d.png $@
+	ffmpeg -r 15 -i images/%06d.png $@
 
 clean:
 	rm -fr $(OBJS) cgol images/
diff --git a/cgol.1 b/cgol.1
@@ -6,6 +6,7 @@
 .Nd generate images of the game of life
 .Sh SYNOPSIS
 .Nm
+.Op Ar width height Op Ar gens
 .Sh DESCRIPTION
 .Nm
 generates frames of the progression of the game of life as images,
@@ -29,9 +30,17 @@ A
 cell remains living only if it has 2 or 3 neighbours.
 .It
 All other cells remain or become dead.
-.Ed
+.El
 According to these rules, the random initial state can give rise to
 some interesting behaviours.
+.Pp
+Options:
+.Bl -tag -width Ds
+.It Ar width height
+the width and height of the images to be printed, in pixels.
+.It Ar gens
+the number of generations to evolve. Must be 0 < gens <= 999999.
+.El
 .Ss Creating a video from the images
 Using a tool such as
 .Xr ffmpeg 1 ,
diff --git a/main.c b/main.c
@@ -2,6 +2,9 @@
  * Copyright (c) 2021 Ben Fuller
  */
 #include "cgol.h"
+#include <errno.h>
+#include <string.h>
+#include <limits.h>
 
 #ifndef __TEST
 #define NROWS 20
@@ -11,11 +14,52 @@
 #define NCOLS 10
 #endif
 
+/* check errno and the result of ato* for an error */
+void
+check(int res) {
+    if (res == 0 && errno != 0) {
+        fprintf(stderr, "bad argument\n");
+        fprintf(stderr, "usage: cgol [width height [gens]]\nthe defaults are \"800\" \"600\" \"200\"\n");
+        exit(1);
+    }
+    errno = 0;
+}
+
+
 int
-main(void) {
-    int n_gens = 200;
+main(int argc, char **argv) {
+    double width, height;
+    int gens;
+
+    if (argc > 1 && strncmp("-h", *(argv + 1), 2) == 0) {
+        fprintf(stderr, "usage: %s [width height [gens]]\nthe defaults are \"800\" \"600\" \"200\"\n", *argv);
+        return 1;
+    }
+    if (argc > 2) {
+        errno = 0;
+        width = atof(*++argv);
+        check(width);
+        height = atof(*++argv);
+        check(height);
+        if (argc > 3) {
+            gens = atoi(*++argv);
+            check(gens);
+            if (gens < 1 || gens > 999999) {
+                /* the upper limit is to ensure the gen number fits onto the
+                 * image filenames */
+                fprintf(stderr, "bad gens arg\n");
+                return 1;
+            }
+        } else
+            gens = 200;
+    } else {
+        width = 800;
+        height = 600;
+        gens = 200;
+    }
+
     struct imgdata img = {
-        400, 400,
+        width, height,
         NROWS, NCOLS,
         { 1, 1, 1, },
         { 0.1, 0.1, 0.1 },
@@ -28,30 +72,27 @@ main(void) {
 #else
     short cells[NROWS][NCOLS] = {
         { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 },
-        { 0, 0, 1, 0, 0, 0, 0, 0, 0, 0 },
-        { 1, 0, 1, 0, 0, 0, 0, 0, 0, 0 },
-        { 0, 1, 1, 0, 0, 0, 0, 0, 0, 0 },
-        { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 },
+        { 0, 0, 1, 0, 0, 1, 0, 0, 0, 0 },
+        { 0, 0, 0, 0, 0, 0, 1, 0, 0, 0 },
+        { 0, 0, 1, 0, 0, 0, 1, 0, 0, 0 },
+        { 0, 0, 0, 1, 1, 1, 1, 0, 0, 0 },
         { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 },
         { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 },
         { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 },
         { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 },
         { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 }
     };
-
-    int x, y;
-    x = 1;
-    y = 2;
-    printf("%d,%d = %hd and has %d neighbours\n", x, y, cells[y][x], neighbours(x, y, &cells[0][0], NCOLS, NROWS));
 #endif
 
     int gen, n_alive;
-    char *fn = malloc(12 + 4);
-    for (gen = 0; gen < n_gens; gen++) {
+    char *fn = malloc(12 + 6);
+    for (gen = 0; gen < gens; gen++) {
 #ifdef __TEST
-        printf("==> GEN %d <==\n", gen);
+        printf("==> GEN %d <==\r", gen);
 #endif
-        sprintf(fn, "images/%04d.png", gen);
+
+        /* %06d because gens <= 999999 */
+        sprintf(fn, "images/%06d.png", gen);
         if (png(&img, &cells[0][0], fn) != 0) {
             free(fn);
             return 1;
@@ -62,6 +103,9 @@ main(void) {
 #endif
     }
     free(fn);
+#ifdef __TEST
+    puts("");
+#endif
 
     return 0;