Lua acceleration thing

  if love.keyboard.isDown('w') then
        y = y - 1
        yv = yv + 1
  end
  if love.keyboard.isDown('a') then
        x = x - 1
        xv = xv + 1
  end
  if love.keyboard.isDown('s') then
        y = y + 1
        yv = yv - 1
  end
  if love.keyboard.isDown('d') then
        x = x + 1
        xv = xv - 1
  end

  x = x - xv
  y = y - yv

  if ( xv > 0 ) then
        xv = xv - 2
  end
  if ( yv > 0 ) then
        yv = yv - 2
  end
  if ( xv < 0 ) then
        xv = xv + 2
  end
  if ( yv < 0 ) then
        yv = yv + 2
  end