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Talking about Space is Key game, Game development, HTML5, Javascript and Phaser.

Here we go with the 3rd step of “Space is Key” HTML5 prototype made using Phaser, tweens and ARCADE physics. In the first step we created the floors and make the player run and jump, then in step 2 we added deadly obstacles to be avoided as well as some level design concepts and now it’s time to show how to make the player die with a particle explosion if the square hits an obstacle. This is what we are going to see today:
Click or tap to jump, avoid obstacles, see how you die when you hit an obstacle. The completely commented source code is here, new lines added from step 2 are highlighted. If you followed previous steps, I moved some code in a function called placeSquare to place the square more easily when the player moves on to next floor or dies.
// the game itself
var game;

// global object with all game options
var gameOptions = {

     // game width
     gameWidth: 640,
     
     // game height 
	gameHeight: 480,
     
     // width of each floor
     floorWidth: 640,
     
     // height of each floor
     floorHeight: 20,
     
     // array with vertical floors potision
     floorY: [100, 220, 340, 460],
     
     // horizontal floor position
     floorX: 0,
     
     // size of the hero
     squareSize: 16,
     
     // horizontal speed of the hero
     squareSpeed: 170,
     
     // game gravity
     squareGravity: 450,
     
     // force to be applied at each jump
     jumpForce: -210,
     
     // jump tween length, in milliseconds
     jumpTime: 500
}

// this is where we store level information
// gameLevels is an array.
// each gameLevel item is an array with floor information
// each gameLevel[floor] item is an object with:
// * obstacle width
// * obstacle height
// * obstacle position
var gameLevels = [
     
     // floor 0
     [
          {
               width: 60,
               height: 30,
               x: 200
          },
          {
               width: 60,
               height: 30,
               x: 400
          }
     ],
     
     // floor 1
     [
          {
               width: 40,
               height: 30,
               x: 250
          },
          {
               width: 70,
               height: 25,
               x: 450
          },
          {
               width: 30,
               height: 20,
               x: 100
          }
     ],
     
     // floor 2
     [
          {
               width: 10,
               height: 35,
               x: 150
          },
          {
               width: 10,
               height: 35,
               x: 300
          },
          {
               width: 10,
               height: 35,
               x: 550
          }
     ],
     
     // floor 3
     [
          {
               width: 80,
               height: 10,
               x: 280
          }
     ]
]

// when the window loads
window.onload = function() {

     // game creation	
	game = new Phaser.Game(gameOptions.gameWidth, gameOptions.gameHeight);
     
     // adding game state
     game.state.add("TheGame", TheGame);
     
     // starting game state
     game.state.start("TheGame");
}

var TheGame = function(){};

TheGame.prototype = {

     // when the state preloads
     preload: function(){
     
          // setting the game on maximum scale mode
          game.scale.scaleMode = Phaser.ScaleManager.SHOW_ALL;
          game.scale.pageAlignHorizontally = true;
          game.scale.pageAlignVertically = true; 
          
          // preloading the only game assets, a tile which will be used both for the square and the floor
		game.load.image("tile", "assets/sprites/tile.png");   
     }, 
     
     // once the state is ready
     create: function(){
     
          // creation of a group where we will place all floors
          this.groundGroup = game.add.group();
          
          // creation of a group where we will place all spikes, or obstacles, or whatever you will name them
          this.spikeGroup = game.add.group();		
          
          // we start on the first floor
          this.levelFloor = 0;
          
          // adding the hero on the first floor
          this.theSquare = game.add.sprite(gameOptions.floorX + gameOptions.squareSize / 2, gameOptions.floorY[0] - gameOptions.squareSize / 2, "tile");
          
          // setting hero registration point
          this.theSquare.anchor.set(0.5);
          
          // setting hero width and height
          this.theSquare.width = gameOptions.squareSize;
          this.theSquare.height = gameOptions.squareSize;
          
          // chen the hero jump?
          this.theSquare.canJump = true;
          
          // enabling ARCADE physics on the hero
          game.physics.enable(this.theSquare, Phaser.Physics.ARCADE);
          
          // setting hero horizontal velocity
          this.theSquare.body.velocity.x = gameOptions.squareSpeed;
          
          // gravity applied to the square
          this.theSquare.body.gravity.y = gameOptions.squareGravity;
          
          // time to create the floors
          for(var i = 0; i < gameOptions.floorY.length; i++){
          
               // each floor is a tile sprite
               var floor = game.add.tileSprite(gameOptions.floorX, gameOptions.floorY[i], gameOptions.floorWidth, gameOptions.floorHeight, "tile");	
               
               // let's enable ARCADE physics on floors too
               game.physics.enable(floor, Phaser.Physics.ARCADE);
               
               // floors can't move
               floor.body.immovable = true;
               
               // adding the floor to ground group
               this.groundGroup.add(floor);
               
               // time to place the spikes
               // let's loop through this level spikes
               for(var j = 0; j < gameLevels[i].length; j++){
               
                    // creating the spike as a tileSprite
                    var spike = game.add.tileSprite(gameOptions.floorX + gameLevels[i][j].x, gameOptions.floorY[i], gameLevels[i][j].width, gameLevels[i][j].height, "tile");
                    
                    // setting spike anchor point
                    spike.anchor.set(0.5, 1);
                    
                    // enabling ARCADE physics to the spike
                    game.physics.enable(spike, Phaser.Physics.ARCADE);
                    
                    // spikes can't move
                    spike.body.immovable = true;
                    
                    // adding the spike to spike group
                    this.spikeGroup.add(spike);			
               }
          }
          
          // placing a particle emitter at coordinates 0, 0 (we'll place it in its proper position later) which can fire up to 30 particles
          this.emitter = game.add.emitter(0, 0, 30);
          
          // our particle is the same old "tile" image
          this.emitter.makeParticles("tile");
          
          // setting a gravity for each particle
          this.emitter.gravity = 200;
          
          // particles would be too big, so let's set their min and max scale.
          this.emitter.maxParticleScale = 0.1;
          this.emitter.minParticleScale = 0.05; 
          
          // waiting for player input, then call squareJump function
          game.input.onDown.add(this.squareJump, this);
     },
     
     // at each frame
     update: function(){
     
          // making the hero collide with floors so it won't fallo down
          game.physics.arcade.collide(this.theSquare, this.groundGroup);
          
          // checking if the hero overlaps with anything in spike group
          game.physics.arcade.overlap(this.theSquare, this.spikeGroup, function(){
          
               // placing the emitter over the player
               this.emitter.x = this.theSquare.x;
               this.emitter.y = this.theSquare.y;
               
               // firing 10 particles at once with a 1000 milliseconds lifespan
               this.emitter.start(true, 1000, null, 10);
               
               // placing the player at the beginning of the floor
               this.placeSquare();
                     
          }, null, this);
          
          // if the hero leaves the floor to the right or to the left...
          if((this.theSquare.x > gameOptions.floorX + gameOptions.floorWidth && this.levelFloor % 2 == 0) || (this.theSquare.x < gameOptions.floorX && this.levelFloor % 2 == 1)){
               
               // increasing floor number or setting it back to zero
               this.levelFloor = (this.levelFloor + 1) % gameOptions.floorY.length; 
               
               // placing player at the beginning of the floor
               this.placeSquare();
          }
          
          // if the hero as its feet on the ground, it can jump
          if(this.theSquare.body.touching.down){
               this.theSquare.canJump = true;
          }
     },
     
     // when the player starts running on a floor
     placeSquare: function(){
               
               // adjusting hero speed according to floor number: from left to right on even floors, from right to left on odd floors
               this.theSquare.body.velocity.x = (this.levelFloor % 2 == 0) ? gameOptions.squareSpeed : -gameOptions.squareSpeed; 
               
               // no vertical velocity
               this.theSquare.body.velocity.y = 0;
               
               // the hero can jump again 
               this.theSquare.canjump = true; 
               
               // adjusting hero vertical and horizontal position
               this.theSquare.y = gameOptions.floorY[this.levelFloor] - gameOptions.squareSize / 2;
               this.theSquare.x = (this.levelFloor % 2 == 0) ? gameOptions.floorX : gameOptions.floorX + gameOptions.floorWidth;   
               
               // stopping the jump tween if running
               if(this.jumpTween && this.jumpTween.isRunning){
                    this.jumpTween.stop();
                    this.theSquare.angle = 0;
               }    
     },
     
     // when the player jumps
     squareJump: function(){
          
          // if the hero can jump...
          if(this.theSquare.canJump){
          
               // preventing it to jump while in the air
               this.theSquare.canJump = false;
               
               // adding a vertical force to the player
               this.theSquare.body.velocity.y = gameOptions.jumpForce;
               
               // setting a jump rotation angle just to make the square rotate
               var jumpAngle = this.levelFloor % 2 == 0 ? 180 : -180;
               
               // using a tween to rotate the player
               this.jumpTween = game.add.tween(this.theSquare).to({
                    angle: this.theSquare.angle + jumpAngle
               }, gameOptions.jumpTime, Phaser.Easing.Linear.None, true);
          }
     }    
}
Would you like to see it turned into a mobile game? Next step I will show you how to do it, meanwhile download the source code.

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