Monkey Game Development：Beginner's Guide
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Time for action — moving the ball

Moving the ball is as simple as moving the paddles, as you will see.

  1. For updating the ball's position, you need to create a new method called UpdateBall. At first, we will update the ball's X and Y position: 
    Method UpdateBall:Int()
bX += bdX 'Add the X speed of the ball to its X position
bY += bdY 'Add the Y speed of the ball to its Y position

    We could end here, but then the ball would not bounce of the walls and would just disappear in nowhere land.

  2. Add a check if the ball hits the top wall and reacts to it. 
    If bY < 10.0 then
bY = 10.0 'Set the Y position back to 10.0
bdY *= -1 'Inverse the balls Y speed
Endif
  3. Next, check if the ball hits the bottom wall and, again, reacts to it. 
    If bY > 470.0 then
bY = 470.0 'Set the Y position back to 470.0
bdY *= -1 'Inverse the balls Y speed
Endif
  4. Now, check against the left wall. If it hits it, add a point to the player's points. 
    If bX < 5.0 then
bX = 5.0 'Set the X position back to 5.0
bdX *= -1 'Inverse the balls X speed
pPoints += 1 'Add 1 to the player's points
  5. As a score was made, check if the victory conditions of 10 points are reached. If yes, set the gameMode to GameOver. After that, close the If statement. 
    If pPoints >= 10 then gameMode = 2
Print (ePoints + ":" + pPoints)
Endif
  6. The last thing in this method will be the check against the right wall. Again, if it hits, add a point to the enemy's points. 
    If bX > 635.0 then
bX = 635.0 'Set the X position back to 635.0
bdX *= -1 'Inverse the balls X speed
ePoints += 1 'Add 1 to the enemies points
  7. The enemy made a score, so check if the victory conditions of 10 points have been reached. If yes, set the gameMode to GameOver. After that, close the If statement. And close the method. 
    If ePoints >= 10 then gameMode = 2
Print (ePoints + ":" + pPoints)
Endif
End
  8. This was one of our biggest methods so far. All we need to do now is to add a call to UpdateBall into the UpdateGame method. 
    ControlEnemies() 'Control the enemy
UpdateBall() 'Update the ball's position
Return True
  9. Phew! We are getting there. Save your game now and test it. The ball should bounce off the walls now, and if it hits the left or right wall, you should see a message with the current score printed.
Time for action — moving the ball

If you need a pre-made source file for the next steps, Pongo_07.Monkey can help you there.

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