Falling Game

local sx, sy = term.getSize()
local cx, cy = sx/2+1, sy/2+1
local gx, gy = 20, sy-1

local gameWindow
local spaceWidth = 3
local playerY = 3
local emptyY = 3
local playerSymbol = "&"

local function randomObstacle( y )
  local x = math.random( 2, gx-1-spaceWidth )
  term.setCursorPos( 1, y )
  term.setBackgroundColor( colors.white )
  term.clearLine()
  paintutils.drawLine( x, y, x + spaceWidth, y, colors.black )
  return x
end

local function play()
  term.setBackgroundColor(colors.gray)
  term.clear()

  gameWindow = window.create( term.current(), cx-gx/2, 2, gx, gy )
  term.redirect(gameWindow)
  term.clear()

  local playerX = gx/2
  parallel.waitForAny( function()
    local i = -1
    local spaces = {}
    while true do
      while #spaces>7 do
        spaces[#spaces] = nil
      end
      i = i<emptyY and i+1 or 0
      if i == 0 then
        table.insert( spaces, 1, randomObstacle( gy ) )
      elseif i == 3 and #spaces > 3 and ( playerX < spaces[4] or playerX > spaces[4] + spaceWidth ) then
        term.setBackgroundColor(colors.red)
        term.setTextColor(colors.red)
        term.setCursorPos( playerX, playerY )
        term.write " "
        return
      end
      sleep(.5)
      term.setCursorPos( playerX, playerY )
      term.write " "
      gameWindow.scroll( 1 )
      term.setCursorPos( playerX, playerY )

      term.write "&"
    end
  end, function()
    while true do
      local _, key = os.pullEvent "key"
      if key == keys.a and playerW ~= 1 then
        playerX = playerX-1
        term.setCursorPos( playerX, playerY )
        term.write( playerSymbol .. " " )
      elseif key == keys.d and playerW ~= gx then
        playerX = playerX+1
        term.setCursorPos( playerX-1, playerY )
        term.write( " " .. playerSymbol )
      end
    end
  end )
end

play()