2 player pong quiz answers

a two-player game of Pong using TWO BBC micro:bits! #LED #number #math #acceleration #docs

Name

Directions

Use this activity document to guide your work in the 2 player pong tutorial

Answer the questions while completing the tutorial. Pay attention to the dialogues!

1. Write the two global variables that record if the player has the ball and if the game is running, and assign these variables to their initial values.

hasBall = false
gameRunning = false

2. Write the global variable that keeps track of the game state in which whoever presses button A first will get to start the ball. Assign this variable to its initial value.

claimBall = true

3. Write the code that creates a condition to know when Button A is pressed. Then write the 'If statement' to ensure that 'claim ball' is true. If the claim ball is true, then write the code that sets P0 to 1 to signal to the other device that the player has claimed the ball.

input.onButtonPressed("A", () => {
    if (claimBall) {
        pins.digitalWritePin("P0", 1)
    }
})

4. Write the code to move the paddle right when button B is pressed. Be sure to check if the game is running and if the paddle is not already on the rightmost edge.

if (gameRunning) {
    if (paddleX != 0) {
        led.unplot(paddleX, 4)
        paddleX = paddleX - 1
        led.plot(paddleX, 4)
    }
}

5. What are the three pieces of information that we send to the other device when transferring the ball? (Hint: look in your "transfer ball" function, and look for any places that contain "transfer byte").

The device first transfers a bit of 1 to indicate that the device is going to transfer the data of the ball. After that, the device transfers the x-coordinate of the ball, and then the x-velocity of the ball.

6. Using the function "read velocity", write the code that reads the x-coordinate and the x-velocity of the ball. (Hint: look at the function "read ball".)

ballX = micro_bitTransfer.readByte()
ballXVelocity = readVelocity()

7. Write the code that updates 'ball x velocity'. (Hint: look at the "update velocity" function.)

if (ballX == 0 || ballX == 4) {
    ballXVelocity = ballXVelocity * (-1)
}

8. Write the code to move the ball. To move the ball, unplot the ball's original position, update its position variables, and then plot the ball's new position.

led.unplot(ballX, 0)
ballX = ballX + ballXVelocity
ballY = ballY + ballYVelocity
led.plot(ballX, ballY)

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