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 example Create a variable to keep score Create new text sprites to tell you if you won or lost Use broadcast and receive to allow sprites to communicate

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