// the game itself
var game;
var gameOptions = {
// maximum length of the sum
maxSumLen: 5,
// local storage name used to save high score
localStorageName: "oneplustwo",
// time allowed to answer a question, in milliseconds
timeToAnswer: 3000,
// score needed to increase difficulty
nextLevel: 400
}
// once the window has been completely loaded...
window.onload = function() {
// create a 500x500 pixels game using CANVAS rendering
game = new Phaser.Game(500, 500, Phaser.CANVAS);
// create "PlayGame" state and start it
game.state.add("PlayGame", playGame, true);
}
// "PlayGame" state
var playGame = function(game){}
playGame.prototype = {
// when the state preloads...
preload: function(){
// making the game cover the biggest window area possible while showing all content
game.scale.scaleMode = Phaser.ScaleManager.SHOW_ALL;
game.scale.pageAlignHorizontally = true;
game.scale.pageAlignVertically = true;
// do not pause the game when it loses focus
game.stage.disableVisibilityChange = true;
// changing background color
game.stage.backgroundColor = 0x444444;
// preloading images
game.load.image("timebar", "timebar.png");
// preloading a spritesheet where each sprite is 400x50 pixels
game.load.spritesheet("buttons", "buttons.png", 400, 50);
},
// when the state has been created...
create: function(){
// it's not game over yet...
this.isGameOver = false;
// current score is set to zero
this.score = 0;
// we'll also keep track of correct answers
this.correctAnswers = 0;
// topScore gets the previously saved value in local storage if any, zero otherwise
this.topScore = localStorage.getItem(gameOptions.localStorageName) == null ? 0 : localStorage.getItem(gameOptions.localStorageName);
// sumsArray is the array with all possible questions
this.sumsArray = [];
// rather than tossing a random question each time, I found easier
// to store all possible questions in an array then draw a random question
// each time. I just need an algorithm to generate all possible questions.
// let's start building all possible questions with this loop
// ranging from 1 (only one operator, like 1+1) to maxSumLen
// (in this case 5, like 1+1+1+1-1-1)
for(var i = 1; i < gameOptions.maxSumLen; i++){
// defining sumsArray[i] as an array of three empty arrays
this.sumsArray[i]=[[], [], []];
// looping from 1 to 3, which are the possible results of each sum
for(var j = 1; j <= 3; j++){
// buildTrees is the core of the script, see it explained
// some lines below
this.buildThrees(j, 1, i, j);
}
}
// try this! You will see all possible combinations
console.log(this.sumsArray);
// questionText is the text object which will display the question
this.questionText = game.add.text(250 , 160, "-", {
font: "bold 72px Arial"
});
// setting questionText registration point
this.questionText.anchor.set(0.5);
// scoreText will keep the current score
this.scoreText = game.add.text(10, 10, "-", {
font: "bold 24px Arial"
});
// loop to create the three answer buttons
for(i = 0;i < 3; i++){
// creation of the answer button, set to frame "i".
// Calls checkAnswer callback function once triggered
var numberButton = game.add.button(50, 250 + i * 75, "buttons", this.checkAnswer, this).frame = i;
}
// adding the time bar
var numberTimer = game.add.sprite(50, 250, "timebar");
// creation of a graphic mask covering the three answer buttons
this.buttonMask = game.add.graphics(50, 250);
this.buttonMask.beginFill(0xffffff);
this.buttonMask.drawRect(0, 0, 400, 200);
this.buttonMask.endFill();
numberTimer.mask = this.buttonMask;
// method to ask next question
this.nextNumber();
},
// buildThrees method, it will find all possible sums
// arguments:
// initialNumber: the first number. Each question always start with a positive number
// currentIndex: it's the amount of operands already placed in the sum
// limit: the max amount of operands allowed in the question
// currentString: the string generated so far
buildThrees: function(initialNummber, currentIndex, limit, currentString){
// the possible operands, from -3 to 3, excluding the zero
var numbersArray = [-3, -2, -1, 1, 2, 3];
// looping from 0 to numbersArray's length
for(var i = 0; i < numbersArray.length; i++){
// "sum" is the sum between the first number and current numberArray item
var sum = initialNummber + numbersArray[i];
// output string is generated by the concatenation of current string with
// current numbersArray item. I am adding a "+" if the item is greater than zero,
// otherwise it already has its "-"
var outputString = currentString + (numbersArray[i] < 0 ? "" : "+") + numbersArray[i];
// if sum is between 1 and 3 and we reached the limit of operands we want...
if(sum > 0 && sum < 4 && currentIndex == limit){
// then push the output string into sumsArray[amount of operands][result]
this.sumsArray[limit][sum - 1].push(outputString);
}
// if the amount of operands is still below the amount we want...
if(currentIndex < limit){
// recursively calling buildThrees, passing as arguments:
// the current sum
// the new amount of operands
// the amount of operands we want
// the current output string
this.buildThrees(sum, currentIndex + 1, limit, outputString);
}
}
},
// this method asks next question
nextNumber: function(){
// updating score text
this.scoreText.text = "Score: " + this.score.toString() + "\nBest Score: " + this.topScore.toString();
// if we already answered more than one question...
if(this.correctAnswers > 1){
// stopping time tween
this.timeTween.stop();
// resetting mask horizontal position
this.buttonMask.x = 50;
}
// if we already answered at least one question...
if(this.correctAnswers > 0){
// tween to slide out the mask, unvealing what's behind it
this.timeTween = game.add.tween(this.buttonMask).to({
x: -350
}, gameOptions.timeToAnswer, Phaser.Easing.Linear.None, true);
// callback to be triggered when the tween ends
this.timeTween.onComplete.add(function(){
// calling "gameOver" method. "?" is the string to display
this.gameOver("?");
}, this);
}
// drawing a random result between 0 and 2 (it will be from 1 to 3)
this.randomSum = game.rnd.between(0, 2);
// choosing question length according to current score
var questionLength = Math.min(Math.floor(this.score / gameOptions.nextLevel) + 1, 4)
// updating question text
this.questionText.text = this.sumsArray[questionLength][this.randomSum][game.rnd.between(0, this.sumsArray[questionLength][this.randomSum].length - 1)];
},
// method to check the answer, the argument is the button pressed
checkAnswer: function(button){
// we check the answer only if it's not game over yet
if(!this.isGameOver){
// button frame is equal to randomSum means the answer is correct
if(button.frame == this.randomSum){
// score is increased according to the time spent to answer
this.score += Math.floor((this.buttonMask.x + 350) / 4);
// one more correct answer
this.correctAnswers++;
// moving on to next question
this.nextNumber();
}
// wrong answer
else{
// if it's not the first question...
if(this.correctAnswers > 1) {
// stop the tween
this.timeTween.stop();
}
// calling "gameOver" method. "button.frame + 1" is the string to display
this.gameOver(button.frame + 1);
}
}
},
// method to end the game. The argument is the string to write
gameOver: function(gameOverString){
// changing background color
game.stage.backgroundColor = "#ff0000";
// displaying game over text
this.questionText.text = this.questionText.text + " = " + gameOverString;
// now it's game over
this.isGameOver = true;
// updating top score in local storage
localStorage.setItem(gameOptions.localStorageName, Math.max(this.score, this.topScore));
// restart the game after two seconds
game.time.events.add(Phaser.Timer.SECOND * 2, function(){
game.state.start("PlayGame");
}, this);
}
}
If you want to play with the source code, download the project and turn it into a complete game.
“1+2=3” HTML5 game made with Phaser updated and commented
Read all posts about "1+2=3" game
A couple of years ago I published a 100 lines html5 prototype of 1+2=3 game using Phaser.
Some months later, I picked uo the prototype, added some kind of story and 132 levels (yes, 132) and released Matt Vs Math, which was sponsored by Softgames.
The prototype remained uncommented and some readers asked me to add comments mostly to know how I was able to generate random questions with increasing difficulty.
Today, I am rewriting the original prototype updated to latest Phaser CE version (2.8.5) and with the game able to restart once it’s game over.
This is the game:
Click or touch the button with 1, 2 or 3 according to the expression shown. What’s your best score? If you have a mobile device, you can play it directly at this link.
And finally this is the source code, commented and updated as you asked:
