conway-001.p8.lua

-- conway's game of life
-- by adam b

world = {}

pw = "a"
nw = "b"

function _init()
  for y = 1,128 do 
    add(world, {})
    for x = 1,128 do
      add(world[y], {a=0,b=0}) 
    end
  end

  -- r pentamino
  local o = 60
  world[1+o][2+o].a = 1
  world[1+o][3+o].a = 1
  world[2+o][1+o].a = 1
  world[2+o][2+o].a = 1
  world[3+o][2+o].a = 1

  -- or just randomize
  set_world()

  cls()      
end

-- randomize world
function set_world()
  for y = 1,128 do
    for x = 1,128 do
      world[y][x][pw] = flr(rnd(2))
    end
  end
end

function check_world()
  for y = 1,128 do
    for x = 1,128 do
      nabes = count_neighbors(x, y)
      if world[y][x][pw] == 0 then
        if nabes == 3 then
          world[y][x][nw] = 1
        else
          world[y][x][nw] = 0
        end
      else
        if nabes == 2 or nabes == 3 then
          world[y][x][nw] = 1
        else 
          world[y][x][nw] = 0
        end
      end      
    end
  end
end

-- neighbors around the cell
offsets = {
  {-1,-1},{0,-1},{1,-1},
  {-1, 0},       {1, 0},
  {-1, 1},{0, 1},{1, 1}
}

function count_neighbors(x, y)
  local sum = 0
  for n, offs in pairs(offsets) do
    nx = x + offs[1]
    if nx == 0 then nx = 128
    elseif nx == 129 then nx = 1
    end

    ny = y + offs[2]
    if ny == 0 then ny = 128
    elseif ny == 129 then ny = 1
    end 

    sum += world[ny][nx][pw]     
  end
  return sum
end

function _update()
  check_world()
  local tw = pw
  pw = nw
  nw = tw 
end

function _draw()
  for y = 1,128 do
    for x = 1,128 do
      if world[y][x][pw] == 1 then
        pset(x, y, 2)
      else
        pset(x, y, 0)
      end
    end
  end 
end