Time for action – moving the paddle with the accelerometer

As mentioned earlier, accelerometer events cannot be tested in the simulator. They only work when a game build is uploaded to a device to see the results. The paddle movement will stay within the wall borders of the level across the x axis. To move the paddle, follow the steps:

1. Below the dragPaddle() function, create a new function called movePaddle(event):

   function movePaddle(event)

2. Add in the accelerometer movement using yGravity. It provides acceleration due to gravity in the y direction:

     paddle.x = display.contentCenterX - (display.contentCenterX * (event.yGravity*3))

3. Add in the wall borders for the level and close the function:

     if((paddle.x - paddle.width * 0.5) < 0) then
       paddle.x = paddle.width * 0.5
     elseif((paddle.x + paddle.width * 0.5) > display.contentWidth) then
       paddle.x = display.contentWidth - paddle.width * 0.5
     end
   end

What just happened?

To make the accelerometer movement work with a device, we have to use yGravity.

Note

Accelerometer events are based on portrait scale when xGravity and yGravity are used accordingly. When display objects are designated for the landscape mode, the xGravity and yGravity values are switched to compensate for the events to work properly.

We have applied the same code for the paddle from function dragPaddle():

  if((paddle.x - paddle.width * 0.5) < 0) then
    paddle.x = paddle.width * 0.5
  elseif((paddle.x + paddle.width * 0.5) > display.contentWidth) then
    paddle.x = display.contentWidth - paddle.width * 0.5
  end

This still keeps the paddle from going past any wall boundaries.