HTML5 String Avoider game made with Phaser

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After the Stencyl version, it’s time to create an HTML5 String Avoider game, using the latest release of Phaser, 2.0.5 at the moment.

The source code is actually a direct port of my AS3 String Avoider version, so I will only comment the lines with actually show something different than the original example.

First, let’s see what we are going to do:

As usual, move the string with the mouse and avoid the maze.

Here is the source code:

<!doctype html>
<html>
	<head>
    		<script src="phaser.min.js"></script>
    		<style>
    			body{margin:0}
    		</style>
    		<script type="text/javascript">
			window.onload = function() {
				var game = new Phaser.Game(640,480,Phaser.CANVAS,"",{
					preload:onPreload,
					create:onCreate,
					update:onUpdate
				});
				
				var tailLength=1;
				var tailNodes=300;
				var nodes = Array();
				var canvas;
				var bitmap;
            		
				// THE GAME IS PRELOADING
				function onPreload() {
					game.load.image("maze", "maze.png");
					for (i=0; i<tailNodes; i++) {
	                		nodes[i]={
						 	x:0,
							 y:0
						};
	            		};
				}
				
				// THE GAME HAS BEEN CREATED
				function onCreate() {
					bitmap = game.make.bitmapData(640,480);
					bitmap.draw("maze");
					bitmap.update();
					game.add.sprite(0,0,bitmap);	
					canvas = game.add.graphics(0,0); 				
				}
							
				// THE GAME IS GOING TO BE UPDATED
				function onUpdate() {
					var touched = false;
					canvas.clear();
					canvas.lineStyle(2,0x00ff00,1);
					var headX=game.input.x;
					var headY=game.input.y;
					canvas.moveTo(headX,headY);
					nodes[0]={
						x:headX,
						y:headY
					};
					for(i=1;i<tailNodes-1;i++){
						var nodeAngle = Math.atan2(nodes[i].y-nodes[i-1].y,nodes[i].x-nodes[i-1].x);
						nodes[i]={
							x: nodes[i-1].x+tailLength*Math.cos(nodeAngle),
							y: nodes[i-1].y+tailLength*Math.sin(nodeAngle) 
						}
						var color = bitmap.getPixel32(Math.round(nodes[i].x),Math.round(nodes[i].y));
						if(!touched && color>0){
							canvas.lineStyle(2,0xff0000,1);
							touched=true
						}
						canvas.lineTo(nodes[i].x,nodes[i].y);
					}
	    			}
	    		};
		</script>
    </head>
    <body>
    </body>
</html>

And now let’s see the interesting lines of this script:

Lines 26-29: unfortunately JavaScript does not support Point variable type, so I am creating new nodes as objects.

Line 35: creation of the bitmap data which will be used to draw the maze

Line 36: finally we draw the maze. Actually, we just paste it from the image loaded at line 24

Line 37: updating the bitmap data. This is very important! Since the bitmap content changed by drawing the maze, it needs to be updated in order to have pixel collision working properly.

Line 60: the core of the game: checking collisions by looking at the pixel under the string to see if it’s transparent.

There is a lot to say about it: first, you must use integer coordinates (that’s why I rounded string values).

Second, it does not work on my iPhone, both using Safari and Chrome. This is really a pity because on my iPhone 5 string movement looks really smooth and could be used for a game, but I wasn’t able to find a way to have pixel color check to work.

Hope someone will found a fix to make it work on iOS browsers.

Meanwhile, download the source code with all libraries included.

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215 GAME PROTOTYPES EXPLAINED WITH SOURCE CODE
// 1+2=3
// 100 rounds
// 10000000
// 2 Cars
// 2048
// A Blocky Christmas
// A Jumping Block
// A Life of Logic
// Angry Birds
// Angry Birds Space
// Artillery
// Astro-PANIC!
// Avoider
// Back to Square One
// Ball Game
// Ball vs Ball
// Ball: Revamped
// Balloon Invasion
// BallPusher
// Ballz
// Bar Balance
// Bejeweled
// Biggification
// Block it
// Blockage
// Bloons
// Boids
// Bombuzal
// Boom Dots
// Bouncing Ball
// Bouncing Ball 2
// Bouncy Light
// BoxHead
// Breakout
// Bricks
// Bubble Chaos
// Bubbles 2
// Card Game
// Castle Ramble
// Chronotron
// Circle Chain
// Circle Path
// Circle Race
// Circular endless runner
// Cirplosion
// CLOCKS - The Game
// Color Hit
// Color Jump
// ColorFill
// Columns
// Concentration
// Crossy Road
// Crush the Castle
// Cube Jump
// CubesOut
// Dash N Blast
// Dashy Panda
// Deflection
// Diamond Digger Saga
// Don't touch the spikes
// Dots
// Down The Mountain
// Drag and Match
// Draw Game
// Drop Wizard
// DROP'd
// Dudeski
// Dungeon Raid
// Educational Game
// Elasticity
// Endless Runner
// Erase Box
// Eskiv
// Farm Heroes Saga
// Filler
// Flappy Bird
// Fling
// Flipping Legend
// Floaty Light
// Fuse Ballz
// GearTaker
// Gem Sweeper
// Globe
// Goat Rider
// Gold Miner
// Grindstone
// GuessNext
// Helicopter
// Hero Emblems
// Hero Slide
// Hexagonal Tiles
// HookPod
// Hop Hop Hop Underwater
// Horizontal Endless Runner
// Hundreds
// Hungry Hero
// Hurry it's Christmas
// InkTd
// Iromeku
// Jet Set Willy
// Jigsaw Game
// Knife Hit
// Knightfall
// Legends of Runeterra
// Lep's World
// Line Rider
// Lumines
// Magick
// MagOrMin
// Mass Attack
// Math Game
// Maze
// Meeblings
// Memdot
// Metro Siberia Underground
// Mike Dangers
// Mikey Hooks
// Nano War
// Nodes
// o:anquan
// One Button Game
// One Tap RPG
// Ononmin
// Pacco
// Perfect Square!
// Perfectionism
// Phyballs
// Pixel Purge
// PixelField
// Planet Revenge
// Plants Vs Zombies
// Platform
// Platform game
// Plus+Plus
// Pocket Snap
// Poker
// Pool
// Pop the Lock
// Pop to Save
// Poux
// Pudi
// Pumpkin Story
// Puppet Bird
// Pyramids of Ra
// qomp
// Quick Switch
// Racing
// Radical
// Rebuild Chile
// Renju
// Rise Above
// Risky Road
// Roguelike
// Roly Poly
// Run Around
// Rush Hour
// SameGame
// SamePhysics
// Save the Totem
// Security
// Serious Scramblers
// Shrink it
// Sling
// Slingy
// Snowflakes
// Sokoban
// Space Checkers
// Space is Key
// Spellfall
// Spinny Gun
// Splitter
// Spring Ninja
// Sproing
// Stabilize!
// Stack
// Stairs
// Stick Hero
// String Avoider
// Stringy
// Sudoku
// Super Mario Bros
// Surfingers
// Survival Horror
// Talesworth Adventure
// Tetris
// The Impossible Line
// The Moops - Combos of Joy
// The Next Arrow
// Threes
// Tic Tac Toe
// Timberman
// Tiny Wings
// Tipsy Tower
// Toony
// Totem Destroyer
// Tower Defense
// Trick Shot
// Tunnelball
// Turn
// Turnellio
// TwinSpin
// vvvvvv
// Warp Shift
// Way of an Idea
// Whack a Creep
// Wheel of Fortune
// Where's my Water
// Wish Upon a Star
// Word Game
// Wordle
// Worms
// Yanga
// Yeah Bunny
// Zhed
// zNumbers