Emanuele Feronato

// the game itself
var game;

// this object contains all customizable game options
// changing them will affect gameplay
var gameOptions = {
	gameWidth: 800,    // game width, in pixels 
	gameHeight: 800,   // game height, in pixels
	tileSize: 100,     // tile size, in pixels 
	fieldSize: {       // field size, an object
          rows: 8,      // rows in the field, in units
          cols: 8       // columns in the field, in units
     },
     colors: [0xff0000, 0x00ff00, 0x0000ff, 0xffff00] // tile colors
}

// function to be execute once the page loads
window.onload = function() {
	
     // creation of a new Phaser Game
	game = new Phaser.Game(gameOptions.gameWidth, gameOptions.gameHeight);
     
     // adding "TheGame" state
     game.state.add("TheGame", TheGame);
     
     // launching "TheGame" state
     game.state.start("TheGame");
}

/* ****************** TheGame state ****************** */ 

var TheGame = function(){};

TheGame.prototype = {

     // function to be executed when the game preloads
     preload: function(){
     
          // setting background color to dark grey
          game.stage.backgroundColor = 0x222222;
          
          // load the only graphic asset in the game, a white tile which will be tinted on the fly
          game.load.image("tiles", "assets/sprites/tile.png"); 
     },
     
     // function to be executed as soon as the game has completely loaded
  	create: function(){
     
          // scaling the game to cover the entire screen, while keeping its ratio
          game.scale.scaleMode = Phaser.ScaleManager.SHOW_ALL;
          
          // horizontally centering the game
		game.scale.pageAlignHorizontally = true;
          
          // vertically centering the game
		game.scale.pageAlignVertically = true;
          
          // this function will create the level
  		this.createLevel();
  	}, 
     
     
	createLevel: function(){
     
          // canPick tells if we can pick a tile, we start with "true" has at the moment a tile can be picked
          this.canPick = true;   
          
          // tiles are saved in an array called tilesArray
          this.tilesArray = [];
          
          // this group will contain all tiles
		this.tileGroup = game.add.group();
          
          // we are centering the group, both horizontally and vertically, in the canvas
          this.tileGroup.x = (game.width - gameOptions.tileSize * gameOptions.fieldSize.cols) / 2;
          this.tileGroup.y = (game.height -  gameOptions.tileSize * gameOptions.fieldSize.rows) / 2;
          
          // two loops to create a grid made by "gameOptions.fieldSize.rows" x "gameOptions.fieldSize.cols" columns
  		for(var i = 0; i < gameOptions.fieldSize.rows; i++){
               this.tilesArray[i] = [];
			for(var j = 0; j < gameOptions.fieldSize.cols; j++){
                    
                    // this function adds a tile at row "i" and column "j"
				this.addTile(i, j);
			}
		}
          
          // tilePool is the array which will contain removed tiles to be recycled
          this.tilePool = [];
          
          // waiting for user input
          game.input.onDown.add(this.pickTile, this);
	},
     
     // function to add a tile at "row" row and "col" column
	addTile: function(row, col){
          
          // determining x and y tile position according to tile size 
		var tileXPos = col * gameOptions.tileSize + gameOptions.tileSize / 2;
		var tileYPos = row * gameOptions.tileSize + gameOptions.tileSize / 2;
		
          // tile is added as an image
          var theTile = game.add.sprite(tileXPos, tileYPos, "tiles");
		
          // setting tile registration point to its center
          theTile.anchor.set(0.5);
          
          // adjusting tile width and height according to tile size
          theTile.width = gameOptions.tileSize;
          theTile.height = gameOptions.tileSize;
          
          // time to assign the tile a random value, which is also a random color
          var tileValue = game.rnd.integerInRange(0, gameOptions.colors.length - 1);
          
          // tinting the tile
          theTile.tint = gameOptions.colors[tileValue];
          
          // adding the image to "tilesArray" array, creating an object
          this.tilesArray[row][col] = {
               tileSprite: theTile, // tile image
               isEmpty: false, // is it an empty tile? not at the moment
               coordinate: new Phaser.Point(col, row), // storing tile coordinate, useful during flood fill
               value: tileValue // the value (color) of the tile
          };
          
          // also adding it to "tileGroup" group
	     this.tileGroup.add(theTile);	
	},
     
     // this function is executed at each user input (click or touch)
     pickTile: function(e){          
     
          // can the player pick a tile?
          if(this.canPick){
          
               // determining x and y position of the input inside tileGroup
               var posX = e.x - this.tileGroup.x;
               var posY = e.y - this.tileGroup.y;
               
               // transforming coordinates into actual rows and columns
               var pickedRow = Math.floor(posY / gameOptions.tileSize);
               var pickedCol = Math.floor(posX / gameOptions.tileSize);
               
               // checking if row and column are inside the actual game field
               if(pickedRow >= 0 && pickedCol >= 0 && pickedRow < gameOptions.fieldSize.rows && pickedCol < gameOptions.fieldSize.cols){
               
                    // this is the tile we picked
                    var pickedTile = this.tilesArray[pickedRow][pickedCol];
                    
                    // the most secure way to have a clean and empty array
                    this.filled = [];
                    this.filled.length = 0;
                    
                    // performing a flood fill on the selected tile
                    // this will populate "filled" array
                    this.floodFill(pickedTile.coordinate, pickedTile.value);
                    
                    // do we have more than one tile in the array?
                    if(this.filled.length > 1){
                    
                         // ok, this is a valid move and player won't be able to pick another tile until all animations have been played
                         this.canPick = false;
                         
                         // function to destroy selected tiles
                         this.destroyTiles();
                    }    
               }               
          }
     },
     
     // this function will destroy all tiles we can find in "filled" array
     destroyTiles: function(){      
     
          // looping through the array
          for(var i = 0; i < this.filled.length; i++){
          
               // fading tile out with a tween
               var tween = game.add.tween(this.tilesArray[this.filled[i].y][this.filled[i].x].tileSprite).to({
                    alpha: 0
               }, 300, Phaser.Easing.Linear.None, true);
               
               // placing the sprite in the array of sprites to be recycled
               this.tilePool.push(this.tilesArray[this.filled[i].y][this.filled[i].x].tileSprite);
               
               // once the tween has been completed...
               tween.onComplete.add(function(e){ 
                    
                    // we don't know how many tiles we have already removed, so counting the tweens
                    // currently in use is a good way, at the moment
                    // if this was the last tween (we only have one tween running, this one) 
                    if(tween.manager.getAll().length == 1){
                    
                         // call fillVerticalHoles function to make tiles fall down
                         this.fillVerticalHoles();     
                    }                                
               }, this);
               
               // now the tile is empty
               this.tilesArray[this.filled[i].y][this.filled[i].x].isEmpty = true;
          }
     },
     
     // this function will make tiles fall down
     fillVerticalHoles: function(){
     
          // filled is a variable which tells us if we filled a hole
          var filled = false;
          
          // looping through the entire gamefield
          for(var i = gameOptions.fieldSize.rows - 2; i >= 0; i--){
               for(var j = 0; j < gameOptions.fieldSize.cols; j++){
               
                    // if we have a tile...
                    if(!this.tilesArray[i][j].isEmpty){
                    
                         // let's count how many holes we can find below this tile
                         var holesBelow = this.countSpacesBelow(i, j);
                         
                         // if holesBelow is greater than zero...
                         if(holesBelow){
                         
                              // we filled a hole, or at least we are about to do it
                              filled = true;
                              
                              // function to move down a tile at column "j" from "i" to "i + holesBelow" row
                              this.moveDownTile(i, j, i + holesBelow, false);                                                                   
                         }
                    }
                    
                         
               }
          }
          
          // if we looped trough all tiles but did not fill anything...
          if(!filled){
          
               // let's see if there are horizontal holes to fill
               this.canPick = true;      
          }
          
          // now it's time to reuse tiles saved in the pool (tilePool array),
          // let's start with a loop through each column
          for(i = 0; i < gameOptions.fieldSize.cols; i++){
          
               // counting how many empty spaces we have in each column
               var topHoles = this.countSpacesBelow(-1, i);
               
               // then for each empty space...
               for(j = topHoles - 1; j >= 0; j--){
               
                    // get the tile to be reused from the pool
                    var reusedTile = this.tilePool.shift();
                    
                    // y position is above the field, to make tile "fall down"
                    reusedTile.y =  (j - topHoles) * gameOptions.tileSize + gameOptions.tileSize / 2;
                    
                    // x position is just the column
                    reusedTile.x = i * gameOptions.tileSize + gameOptions.tileSize / 2;
                    
                    // setting alpha back to 1
                    reusedTile.alpha = 1;
                    
                    // setting a new tile value
                    var tileValue = game.rnd.integerInRange(0, gameOptions.colors.length - 1);
                    
                    // tinting the tile with the new color
                    reusedTile.tint = gameOptions.colors[tileValue];    
                    
                    // setting the item with the new values
                    this.tilesArray[j][i] = {
                         tileSprite: reusedTile,
                         isEmpty: false,
                         coordinate: new Phaser.Point(i, j),
                         value: tileValue
                    }  
                    
                    // and finally make the tile fall down
                    this.moveDownTile(0, i, j, true);                    
               }
          }
     },
     
     // function to count how many empty tiles we have under a given tile
     countSpacesBelow: function(row, col){
          var result = 0;
          for(var i = row + 1; i < gameOptions.fieldSize.rows; i++){
               if(this.tilesArray[i][col].isEmpty){
                    result ++;
               }     
          }
          return result;
     },
     
     // function to move down a tile
     moveDownTile: function(fromRow, fromCol, toRow, justMove){
     
          // a tile can be just moved (when it's a "new" tile falling from above) or 
          // must be moved updating the game field (when it's an "old" tile falling down from its previous position)
          // "justMove" flag handles this operation
          if(!justMove){
          
               // saving the tile itself and its value in temporary variables
               var tileToMove = this.tilesArray[fromRow][fromCol].tileSprite;
               var tileValue = this.tilesArray[fromRow][fromCol].value;
          
               // adjusting tilesArray items actually creating the tile in the new position...
               this.tilesArray[toRow][fromCol] = {
                    tileSprite: tileToMove,
                    isEmpty: false,
                    coordinate: new Phaser.Point(fromCol, toRow),
                    value: tileValue
               }  
               
               // the old place now is set to null
               this.tilesArray[fromRow][fromCol].isEmpty = true;        
          }
          
          // distance to travel, in pixels, by the tile
          var distanceToTravel = (toRow * gameOptions.tileSize + gameOptions.tileSize / 2) - this.tilesArray[toRow][fromCol].tileSprite.y
          
          // a tween manages the movement
          var tween = game.add.tween(this.tilesArray[toRow][fromCol].tileSprite).to({
               y: toRow * gameOptions.tileSize + gameOptions.tileSize / 2         
          }, distanceToTravel / 2, Phaser.Easing.Linear.None, true);
          
          // same thing as before to see how many tweens remain alive, and if this is the last
          // active tween, call "fillHorizontalHoles" function
          tween.onComplete.add(function(){
               if(tween.manager.getAll().length == 1){
                    this.canPick = true;
               }
          }, this)
          
     },
     
     // function which counts tiles in a column
     tilesInColumn: function(col){
          var result = 0;
          for(var i = 0; i < gameOptions.fieldSize.rows; i++){
               if(!this.tilesArray[i][col].isEmpty){ 
                    result ++;
               }
          }
          return result;
     },
     
     // flood fill function, for more information
     // http://emanueleferonato.com/2008/06/06/flash-flood-fill-implementation/
     floodFill: function(p, n){
          if(p.x < 0 || p.y < 0 || p.x >= gameOptions.fieldSize.cols || p.y >= gameOptions.fieldSize.rows){
               return;
          }
          if(!this.tilesArray[p.y][p.x].isEmpty && this.tilesArray[p.y][p.x].value == n && !this.pointInArray(p)){
               this.filled.push(p);
               this.floodFill(new Phaser.Point(p.x + 1, p.y), n);
               this.floodFill(new Phaser.Point(p.x - 1, p.y), n); 
               this.floodFill(new Phaser.Point(p.x, p.y + 1), n);
               this.floodFill(new Phaser.Point(p.x, p.y - 1), n);       
          }
     },
     
     // there isn't a built-in javascript method to see if an array contains a point, so here it is.
     pointInArray: function(p){
          for(var i = 0; i < this.filled.length; i++){
               if(this.filled[i].x == p.x && this.filled[i].y == p.y){
                    return true;
               }
          }
          return false;
     }
}