#!/usr/bin/env perl
use strict;
use warnings;
use 5.016;

use PDL;

sub conway {
    my $pdl = shift;
    die "Not 2D piddle" unless $pdl->ndims == 2;

    # Add up all values:
    my $tmp = $pdl +                                       # original
      $pdl->transpose->rotate(-1)->transpose +             # north
      $pdl->transpose->rotate(-1)->transpose->rotate(-1) + # northeast
      $pdl->rotate(-1) +                                   # east
      $pdl->transpose->rotate(1)->transpose->rotate(-1) +  # southeast
      $pdl->transpose->rotate(1)->transpose +              # south
      $pdl->transpose->rotate(1)->transpose->rotate(1) +   # southwest
      $pdl->rotate(1) +                                    # west
      $pdl->transpose->rotate(-1)->transpose->rotate(1);   # northwest

    # Cell is alive if it's either:
    return ( $tmp == 4 & $pdl == 1 ) |    # Alive +3 neighbors
      $tmp == 3;    #  Alive +2 neighbors or dead +3 neighbors
}

my $arena = pdl(byte,
    [
        [ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 ],
        [ 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 ],
        [ 0, 1, 0, 1, 0, 0, 0, 0, 0, 0, 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, 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, 0, 0, 0, 0 ],
    ]
);

my $gen = 0;
while (1) {
    print "Generation: $gen (press enter for next)\n";
    print $arena;
    $arena = conway($arena);
    $gen++;
    exit if <STDIN> ne "\n";
}