local Screen = require("screen")
local mode = 15
local fps, _fps, second = 0, 0, 0

function _init()
  sys.stepinterval(0)
  scrn = Screen:new("Static", 15, 4)
  scrn:colors(15, 0)
  zoom(0)
  for i = 0, 15 do
    scrn:palette(i, i, i, i)
  end
end

function _step(t)
  local btn = input.gamepad()
  if _lastbtn == 0 and btn & 16 > 0 then -- A
    zoom(-32)
  end
  if _lastbtn == 0 and btn & 32 > 0 then -- B
    zoom(5)
  end
  if _lastbtn == 0 and btn & 64 > 0 then -- X
    zoom(1)
  end
  if _lastbtn == 0 and btn & 128 > 0 then -- Y
    zoom(4)
  end
  _lastbtn = btn
  view.active(scrn.mainvp)
  for y = 0, scrnh do
    for x = 0, scrnw do
      gfx.pixel(x, y, math.random(0, 15))
    end
  end
  if input.hotkey() == "q" then
    sys.exit(0)
  end
  _fps = _fps + 1
  if second ~= math.floor(t / 1000) then
    second = math.floor(t / 1000)
    fps = _fps
    _fps = 0
    scrn:title("Mode:" .. mode .. " FPS:" .. fps)
  end
  scrn:step()
end

function zoom(amount)
  mode = mode + amount
  if mode < 0 then
    mode = 0
  end
  while mode >= 16 do
    mode = mode - 16
  end
  scrn:mode(mode, 4)
  scrnw, scrnh = scrn:size()
end