Extending the Pong Example
Barb Ericson
Georgia Tech
June 2011
Goals
• Learn about
– Creating a variable to keep score
– Displaying text to let the user know if s/he
won or lost
– Using broadcast and receive to allow sprites to
communicate
Project Description
• We will add to the example in Games – 4 Pong to add a
score that is displayed and tell you if you won or lost.
Big Picture
• Open the pong game • Use broadcast and
example
receive to allow
sprites to
• Create a variable to
communicate
keep score
• Create new text
sprites to tell you if
you won or lost
Open the Pong game
• Click on File
then Open
• Select
Examples
and games
and open 4
Pong
Create a variable
• Click on
"Variables" and
then on "Make a
variable"
• Name the
variable score
– Click "OK"
Variable Tiles
• When you create a new
variable a set of 5 tiles are
created
– First controls the display of
the variable
• Uncheck to not display
– Second sets the value of the
variable
– Third changes the value
– Fourth shows the value
– Fifth hides the value
Start Score at 0
• Drag "set score
to 0" from
"Variables"
category after
the "go to x: 13
y:157"
Increment Score
• When the paddle
hits the ball
– Drag "change
score by 1" from
"Variables"
– Drop before
"move 5 steps"
Draw text sprites
• Use the paint
editor to paint
text sprites
• Select T for text
– Select font type
and size
– Select color
– Type the text
Hide text sprites
• Select sprite
under stage view
– Select Scripts tab
– Drag out "when
green flag
clicked" from
"Control"
– Drag out "hide"
from "Looks"
Broadcast when lost
• Two sprites can
communicate using
broadcast and receive
– Have the ball
broadcast the message
"lost"
– Click the down arrow
to create a new
message
Show text sprite
• When the "You
Lost!" text
sprite receives
the message
"lost"
– Show the sprite
Add a way to win
• When the score
equals 5 tell the
user s/he won
– And show "You
Won!" sprite
– Stop execution
of all scripts
Challenges
• Make the ball speed up over time
– Add another variable named speed
– Move by speed each time you hit the ball
with the paddle
• Play a sound when you lose or win
• Try to create two player game with
two paddles
Concept Summary
• Variables
– Can be displayed
– Can be set to a value
– The value can be changed
• Incremented or decremented
• You can create text sprites
– That you hide when the game starts
• Two sprites can communicate using
broadcast and receive