Talking about Crossy Road game, Game development, HTML5, Javascript and Phaser.
You should already know how to create a HTML draggable and scrollable map with inertia using Phaser framework. One of the most interesting things of scrollable maps is you can basically use their core concepts to create a lot of other stuff. Today I am showing you how to create a character selection screen changing only a few lines. And I’ll also include a bounce effect when the map reaches its edges. Character selection is a very popular feature in endless runner games, where the player can collect a currency to unlock new characters, just like in Crossy Road game.
So, this is what we are going to create starting from the draggable map:
Drag the screen or swipe to move the fishes. The closest fish to the middle of the canvas is the currently selected fish. Also notice the bounce effect.
What did I need to change to the original prototype to get to this result?
First, the “scrolling map” is no longer a sprite or an image but a transparent tilesprite and is not longer draggable as you want but only horizontally.
Then we have some white fishes colored by applying a tint color added to the tilesprite as children, and that’s it.
Dragging and scrolling the invisible tilesprite, all fishes will move accordingly. The bouce effect is achieved by adding 180 degrees to the angle of movement if the tilesprite reaches its left or right minimum position, as well as heavily decreasing the speed.
This is the source code, as you can see is really similar to the original:
var game;
var speedMult = 0.7;
var friction = 0.99;
var colors = ["0xac81bd","0xff5050","0xdab5ff","0xb5ffda","0xfffdd0","0xcc0000","0x54748b","0x4b0082","0x80ab2f","0xff784e","0xe500db","0x223c4a","0x223c4a","0xf1290e","0x648080","0xbbc1c4","0x6f98a2","0x71717e"];
window.onload = function() {
game = new Phaser.Game(320, 480, Phaser.AUTO, "");
game.state.add("PlayGame", playGame);
game.state.start("PlayGame");
}
var playGame = function(game){};
playGame.prototype = {
preload: function(){
game.load.image("fish", "fish.png");
game.load.image("transp", "transp.png");
},
create: function(){
game.stage.backgroundColor = "#000044";
game.add.text(game.width / 2, 50, "Select your fish", {font: "18px Arial", fill: "#ffffff"}).anchor.set(0.5);
this.scrollingMap = game.add.tileSprite(0, 0, game.width / 2 + colors.length * 90 + 64, game.height, "transp");
this.scrollingMap.inputEnabled = true;
this.scrollingMap.input.enableDrag(false);
this.scrollingMap.savedPosition = new Phaser.Point(this.scrollingMap.x, this.scrollingMap.y);
this.scrollingMap.isBeingDragged = false;
this.scrollingMap.movingSpeed = 0;
this.scrollingMap.input.allowVerticalDrag = false;
this.scrollingMap.input.boundsRect = new Phaser.Rectangle(game.width - this.scrollingMap.width, game.height - this.scrollingMap.height, this.scrollingMap.width * 2 - game.width, this.scrollingMap.height * 2 - game.height);
for(var i = 0; i < colors.length; i++){
var fish = game.add.image(game.width / 2 + i * 90, game.height / 2, "fish");
fish.anchor.set(0.5);
fish.tint = colors[i];
this.scrollingMap.addChild(fish)
}
this.scrollingMap.events.onDragStart.add(function(){
this.scrollingMap.isBeingDragged = true;
this.scrollingMap.movingSpeed = 0;
}, this);
this.scrollingMap.events.onDragStop.add(function(){
this.scrollingMap.isBeingDragged = false;
}, this);
},
update:function(){
var zoomed = false;
for(var i = 0; i < this.scrollingMap.children.length; i++){
if(Math.abs(this.scrollingMap.children[i].world.x - game.width / 2) < 46 && !zoomed){
this.scrollingMap.getChildAt(i).scale.setTo(1.5);
zoomed = true;
}
else{
this.scrollingMap.getChildAt(i).scale.setTo(1);
}
}
if(this.scrollingMap.isBeingDragged){
this.scrollingMap.savedPosition = new Phaser.Point(this.scrollingMap.x, this.scrollingMap.y);
}
else{
if(this.scrollingMap.movingSpeed > 1){
this.scrollingMap.x += this.scrollingMap.movingSpeed * Math.cos(this.scrollingMap.movingangle);
if(this.scrollingMap.x < game.width - this.scrollingMap.width){
this.scrollingMap.x = game.width - this.scrollingMap.width;
this.scrollingMap.movingSpeed *= 0.5;
this.scrollingMap.movingangle += Math.PI;
}
if(this.scrollingMap.x > 0){
this.scrollingMap.x = 0;
this.scrollingMap.movingSpeed *= 0.5;
this.scrollingMap.movingangle += Math.PI;
}
this.scrollingMap.movingSpeed *= friction;
this.scrollingMap.savedPosition = new Phaser.Point(this.scrollingMap.x, this.scrollingMap.y);
}
else{
var distance = this.scrollingMap.savedPosition.distance(this.scrollingMap.position);
var angle = this.scrollingMap.savedPosition.angle(this.scrollingMap.position);
if(distance > 4){
this.scrollingMap.movingSpeed = distance * speedMult;
this.scrollingMap.movingangle = angle;
}
}
}
}
}
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