test.lua

local component = require("component")
local keyboard = require("keyboard")
local gpu = component.gpu
local screen = component.screen
gpu.bind(screen.address)

local foreColor = 0xC3C3C3
local backColor = 0x5A5A5A

local direction = {0,0}

local w,h = gpu.getResolution()
local Square = {pos = {5,5}, width = 6, height = 3, lastPos = {5,5}, color = 0xFF0000}

function Square:draw ()
  gpu.fill(self.lastPos[1], self.lastPos[2], self.width, self.height, " ")
  gpu.setBackground(self.color)
  gpu.fill(self.pos[1], self.pos[2], self.width, self.height, " ")
  gpu.setBackground(backColor)
end

function Square:update ()
  self.lastPos[1] = self.pos[1]
  self.lastPos[2] = self.pos[2]
  self.pos[1] = math.min(math.max(1, self.pos[1] + direction[1]),w-self.width)
  self.pos[2] = math.min(math.max(1, self.pos[2] + direction[2]),h-self.height)
end

function getDirection()
  direction[1] = 0
  direction[2] = 0
  -- 'w'
  if keyboard.isKeyDown(0x11) then direction[2] = -1
  -- 's'
  elseif keyboard.isKeyDown(0x1F) then direction[2] = 1
  end
  -- 'a'
  if keyboard.isKeyDown(0x1E) then direction[1] = -2
  -- 'd'
  elseif keyboard.isKeyDown(0x20) then direction[1] = 2
  end
end


gpu.setForeground(foreColor)
gpu.setBackground(backColor)
gpu.fill(1,1,w,h," ")


while(true) do
  getDirection()
  Square:update()
  Square:draw()
  os.sleep(0.032)
end