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Falling balloons

codeguppy profile image Adrian ・3 min read

Intro

Falling balloons is a game of skills. You need to quickly pop the falling balloons before they hit the ground.

While implementing this mini-game, you’ll learn important concepts such as:

  • How to create multi-scene games
  • How to update and display several moving objects

What do you need?

To run the code in this article you don’t need to install anything on your local computer.

Just open the online JavaScript playground from codeguppy.com/code.html and copy and paste the following code in the integrated editor.

When ready, press the “Play” button to run the code.

Source code

This program contains multiple scenes. Please copy and paste each scene in a separate code page. Make sure the name of the scene is as indicated below.

Scene: Intro

var startGame = false;

function enter()
{
    background('Scene1');
    cursor(ARROW);    
}

function loop()
{
    clear();
    drawIntroScreen();        
}

function mouseClicked()
{
    if (startGame)
    {
        showScene( "Game" );
    }
}

function drawIntroScreen()
{
    var ballX = width / 2;
    var ballY = height / 2;
    var ballSize = height / 2;

    stroke(1);
    fill("yellow");
    ellipse( ballX, ballY, ballSize );

    noStroke();
    fill("black");

    textSize(24);
    textAlign(CENTER);
    text("Catch\nthe\nfalling balls", width / 2, height / 2 - 30);

    if ( Math.floor(frameCount / 30) % 2 === 0 ) 
    {
        textSize(12);
        text("Click the ball to start the game...", width / 2, height - 20);
    }

    if ( dist( mouseX, mouseY, ballX, ballY ) < ballSize / 2  )
    {
        noFill();
        stroke(1);
        ellipse( ballX, ballY, ballSize + 10 );
        startGame = true;
    }
}

Scene: Game

var maxBallsDropped = 10;

var balls;
var ballsDropped;
var ballsCaught;

function initGame()
{
    balls = [];
    ballsDropped = 0;
    ballsCaught = 0;

    for(var i = 0; i < 10; i++)
    {
        addBall(balls);
    }
}

function enter()
{
    background('Scene2');
    noCursor();

    textSize(12);
    textAlign(LEFT);

    initGame();
}

function loop()
{
    clear();

    displayBalls(balls);
    updateBalls(balls);
    displayNeedle();

    displayStats();
}


function displayNeedle()
{
    stroke(1);
    noFill();
    triangle(mouseX, mouseY, mouseX - 10, mouseY + 10, mouseX - 8, mouseY + 15);
}

function displayGlobalBalls()
{
    displayBalls(balls);
}

function catchBall(ball)
{
    if ( ballsDropped < maxBallsDropped )
    {
        ballsCaught++;
        initBall(ball);
    }
}

function displayBalls(arBalls)
{
    for(var i = 0; i < arBalls.length; i++)
    {
        displayBall( arBalls[i] );
    }
}

function displayBall(ball)
{
    fill(ball.color);
    stroke(1);
    ellipse(ball.x, ball.y, ball.size);

    if ( dist( mouseX, mouseY, ball.x, ball.y ) < ball.size / 2 )
    {
        noFill();
        ellipse(ball.x, ball.y, ball.size + 5);

        catchBall(ball);
    }
}

function displayStats()
{
    fill("black");
    noStroke();
    text( "Caught: " + ballsCaught, 10, height - 40);
    text( "Dropped: " + ballsDropped, 10, height - 20);
}


function updateBalls(arBalls)
{
    for(var i = 0; i < arBalls.length; i++)
    {
        updateBall( arBalls[i] );
    }
}

function updateBall(ball)
{
    ball.y += ball.size / 20 + ballsCaught / 100;

    // test if hits the ground
    if ( ball.y > height )
    {
        ballsDropped++;

        if ( ballsDropped >= maxBallsDropped )
        {
            showScene( "GameOver", ballsCaught );
        }

        // reinit the ball
        initBall(ball);
    }
}

function addBall(arBalls)
{
    var ball = { x : 0, y : 0, color : "", size: 10 };
    initBall(ball);

    arBalls.push(ball);
}

function initBall(ball)
{
    ball.x = random(10, width - 10);
    ball.y = 10;
    ball.color = random(["white", "yellow", "green", "blue", "red"]);
    ball.size = random(10, 30);
}

Scene: GameOver

function enter()
{
    background('Scene');
    cursor(ARROW);
}

function loop()
{
    clear();

    fill("black");
    noStroke();
    textSize( map( sin(frameCount * 0.1), 0, 1, 24, 32) );
    textAlign(CENTER);
    text("GAME OVER", width / 2, height / 2);

    textSize(12);
    text("Score: " + PublicVars.Arguments, width / 2, height / 2 + 20);

    text("Click mouse button to restart game...", width / 2, height - 20);
}

function mouseClicked()
{
    showScene( "Intro" );
}

Feedback

If you liked the article, please follow @codeguppy on Twitter and / or visit codeguppy.com for more tutorials and projects.

Also, if you want to extend this article with detailed instructions explaing how to build the program step by step, please leave feedback in the comments.

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