Page 126 - Scratch Programming Playground

You’ll use the broadcast message in script u to control
what happens when the ball touches the paddle in script v.
The point in direction 180 - direction code in script v
might seem a bit mysterious, but this simple equation cal-
culates the direction in which the ball will bounce based on
the ball’s current direction. If the ball is pointed up and right
(45 degrees), then when it bounces off the bottom of a brick,
its new direction will be down and right (135 degrees, because
180 – 45 = 135). If the ball is pointed up and left (−45 degrees),
then when it bounces off the bottom of a brick, its new direction
will be down and left (225 degrees, because 180 – (–45) = 225).

Ball pointed Ball pointed
up and right up and le

180 – 45 = 135 180 – (–45) = 225

You’ll use this broadcast message again later in the pro-
gram when you add code to make the ball bounce off the
bricks.

100 ChapTer 5