pxt-calliope/docs/reference/js/lessons/pong/quiz-answers.md
2016-03-25 16:47:20 -07:00

1.8 KiB

pong quiz answers

create the game Pong #LED #number #math #acceleration #docs

Name

Directions

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

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

1. Create two variables that will keep track of the x-position and y-position of the ball, and assign the variables to their initial values.


ballX = 2
ballY = 1

2. Create two variables that keeps track of the velocity (or the speed and direction) of the ball, and assign the variables to their initial values.


ballXVelocity = 1
ballYVelocity = 1

3. Write the code that plots the initial position of the paddle and the ball.


led.plot(0, paddleY)
led.plot(ballX, ballY)

4. Write the code that moves the paddle up when Button A is pressed. (Don't worry about setting 'game running' to true.)


input.onButtonPressed("A", () => {
    if (paddleNotUp()) {
        led.unplot(0, paddleY)
        paddleY = paddleY - 1
        led.plot(0, paddleY)
    }
})

5. Write the code that moves the paddle up when Button B is pressed. (Don't worry about setting 'game running' to true.)


input.onButtonPressed("A", () => {
    if (paddleNotDown()) {
        led.unplot(0, paddleY)
        paddleY = paddleY + 1
        led.plot(0, paddleY)
    }
})

6. Write the code to update the y-velocity. (Hint: look at the function "update y velocity".)


if (ballY == 4 || ballY == 0) {
    ballYVelocity = (-1) * ballYVelocity
}

7. Write the code to move the ball. (Hint: look at the function "move ball".)


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