Emanuele Feronato

Talking about Game development, HTML5, Javascript and Phaser.

If you are planning to create a game with levels, you should also provide a level select screen. Also, in modern games, beating the level is not the main aim of the game, you will need to complete the level earning three stars if you want to say you really completed the level.

I am going to show you a Phaser prototype to create a multiple pages level select screen with scrolling and a shake effect if you try to play locked levels.

This is what we are going to build, the level select screen of a 60 levels game, with levels split on three 20-levels page:

It’s just a matter of managing buttons and sprite sheet, these are the graphic assets I used:

for the arrows, and

for level thumbnails.

Then, the fully commented script is very easy to understand and to expand:

var game = new Phaser.Game(320, 480, Phaser.AUTO, "", {preload: onPreload, create: onCreate});

// number of thumbnail rows
var thumbRows = 5;
// number of thumbnail cololumns
var thumbCols = 4;
// width of a thumbnail, in pixels
var thumbWidth = 64;
// height of a thumbnail, in pixels
var thumbHeight = 64;
// space among thumbnails, in pixels
var thumbSpacing = 8;
// array with finished levels and stars collected.
// 0 = playable yet unfinished level
// 1, 2, 3 = level finished with 1, 2, 3 stars
// 4 = locked
var starsArray = [1,2,1,2,3,3,3,2,2,1,3,1,0,4,4,4,4,4,4,4,4,4,4,4,4,4,4,4,4,4,4,4,4,4,4,4,4,4,4,4,4,4,4,4,4,4,4,4,4,4,4,4,4,4,4,4,4,4,4,4];
// how many pages are needed to show all levels?
// CAUTION!! EACH PAGE SHOULD HAVE THE SAME AMOUNT OF LEVELS, THAT IS
// THE NUMBER OF LEVELS *MUST* BE DIVISIBLE BY THUMBCOLS*THUMBROWS
var pages = starsArray.length/(thumbRows*thumbCols);
// group where to place all level thumbnails
var levelThumbsGroup;
// current page
var currentPage = 0;
// arrows to navigate through level pages
var leftArrow;
var rightArrow;

// preloading graphic assets
function onPreload() {
	game.load.spritesheet("levels", "levels.png", 64, 64);
	game.load.spritesheet("level_arrows", "level_arrows.png", 48, 48);
}

// going fullscreen
function goFullScreen(){
	game.scale.pageAlignHorizontally = true;
	game.scale.pageAlignVertically = true;
	game.scale.scaleMode = Phaser.ScaleManager.SHOW_ALL;
	game.scale.setScreenSize(true);
}

function onCreate() {
	goFullScreen();
	// placing left and right arrow buttons, will call arrowClicked function when clicked
	leftArrow = game.add.button(50,420,"level_arrows",arrowClicked);
	leftArrow.anchor.setTo(0.5);
	leftArrow.frame = 0;
	leftArrow.alpha = 0.3;
	rightArrow = game.add.button(270,420,"level_arrows",arrowClicked);
	rightArrow.anchor.setTo(0.5);
	rightArrow.frame = 1;
	// creation of the thumbails group
	levelThumbsGroup = game.add.group();
	// determining level thumbnails width and height for each page
	var levelLength = thumbWidth*thumbCols+thumbSpacing*(thumbCols-1);
	var levelHeight = thumbWidth*thumbRows+thumbSpacing*(thumbRows-1);
	// looping through each page
	for(var l = 0; l < pages; l++){
		// horizontal offset to have level thumbnails horizontally centered in the page
		var offsetX = (game.width-levelLength)/2+game.width*l;
		// I am not interested in having level thumbnails vertically centered in the page, but
		// if you are, simple replace my "20" with
		// (game.height-levelHeight)/2
		var offsetY = 20;
		// looping through each level thumbnails
	     for(var i = 0; i < thumbRows; i ++){
	     	for(var j = 0; j < thumbCols; j ++){  
	     		// which level does the thumbnail refer?
				var levelNumber = i*thumbCols+j+l*(thumbRows*thumbCols);
				// adding the thumbnail, as a button which will call thumbClicked function if clicked   		
				var levelThumb = game.add.button(offsetX+j*(thumbWidth+thumbSpacing), offsetY+i*(thumbHeight+thumbSpacing), "levels", thumbClicked, this);	
				// shwoing proper frame
				levelThumb.frame=starsArray[levelNumber];
				// custom attribute 
				levelThumb.levelNumber = levelNumber+1;
				// adding the level thumb to the group
				levelThumbsGroup.add(levelThumb);
				// if the level is playable, also write level number
				if(starsArray[levelNumber]<4){
					var style = {
						font: "18px Arial",
						fill: "#ffffff"
					};
					var levelText = game.add.text(levelThumb.x+5,levelThumb.y+5,levelNumber+1,style);
					levelText.setShadow(2, 2, 'rgba(0,0,0,0.5)', 1);
					levelThumbsGroup.add(levelText);
				}
			}
		}
	}
}

function thumbClicked(button){
	// the level is playable, then play the level!!
	if(button.frame < 4){
		alert("playing level " + button.levelNumber);
	}
	// else, let's shake the locked levels
	else{
		var buttonTween = game.add.tween(button)
		buttonTween.to({
			x: button.x+thumbWidth/15
		}, 20, Phaser.Easing.Cubic.None);
		buttonTween.to({
			x: button.x-thumbWidth/15
		}, 20, Phaser.Easing.Cubic.None);
		buttonTween.to({
			x: button.x+thumbWidth/15
		}, 20, Phaser.Easing.Cubic.None);
		buttonTween.to({
			x: button.x-thumbWidth/15
		}, 20, Phaser.Easing.Cubic.None);
		buttonTween.to({
			x: button.x
		}, 20, Phaser.Easing.Cubic.None);
		buttonTween.start();
	}
}


function arrowClicked(button){
	// touching right arrow and still not reached last page
	if(button.frame==1 && currentPage<pages-1){
		leftArrow.alpha = 1;
		currentPage++;
		// fade out the button if we reached last page
		if(currentPage == pages-1){
			button.alpha = 0.3;
		}
		// scrolling level pages
		var buttonsTween = game.add.tween(levelThumbsGroup);
		buttonsTween.to({
			x: currentPage * game.width * -1
		}, 500, Phaser.Easing.Cubic.None);
		buttonsTween.start();
	}
	// touching left arrow and still not reached first page
	if(button.frame==0 && currentPage>0){
		rightArrow.alpha = 1;
		currentPage--;
		// fade out the button if we reached first page
		if(currentPage == 0){
			button.alpha = 0.3;
		}
		// scrolling level pages
		var buttonsTween = game.add.tween(levelThumbsGroup);
		buttonsTween.to({
			x: currentPage * game.width * -1
		}, 400, Phaser.Easing.Cubic.None);
		buttonsTween.start();
	}		
}

Now, you just have to locally save completed levels to allow players to continue playing starting from where they left. You can also download the source code of the entire project.