feat: remove math (#11)

* feat: remove math

* working

* remove unused stdint

* small fix

src/args.c

@@ -23,7 +23,7 @@ void print_help(int status_code) {
        "[-va=R,G,B] "
        "[-vr=VAR_RANGE] "
        "[-r=ROTATION] "
-       //  "[-m]"
+       "[-m]"
        "\n\n"
        "generate a marble-like pattern bitmap image, blazing fast.\n\n"
        "options:\n"
@@ -216,9 +216,9 @@ parameters parse_args(int argc, char **argv) {
   }
 
   if (!var_set) {
-    params.var[0] = rand_uchar(var_range);
-    params.var[1] = rand_uchar(var_range);
-    params.var[2] = rand_uchar(var_range);
+    params.var[0] = rand_uchar(var_range + 1);
+    params.var[1] = rand_uchar(var_range + 1);
+    params.var[2] = rand_uchar(var_range + 1);
   }
 
   if (!rot_set) {