Placing platforms randomly in world

[Julia]

I'm making a vertical scrolling platform game using Phaser, but I can't figure out how to create randomly placed platforms to jump on. This is the code I have so far (removed unneccesary stuff):

Platformer.Game = function (game) {
this._platforms = null;
this._platform = null;
this._numberOfPlatforms = 15;
this._x = this.x;
this._y = this.y;
};

Platformer.Game.prototype = {
create: function (){
this.physics.startSystem(Phaser.Physics.ARCADE);
this.physics.arcade.gravity.y = 200;

this._platforms = this.add.group();
Platformer.platform.createPlatform(this);
Platformer.platform.createPlatform(this);
Platformer.platform.createPlatform(this);
Platformer.platform.createPlatform(this);
Platformer.platform.createPlatform(this);
Platformer.platform.createPlatform(this);

game.camera.follow(this._player);

},

managePause: function () {
this.game.paused = true;
var pausedText = this.add.text(100, 250, "Game paused. Click anywhere to continue.", this._fontStyle);
this.input.onDown.add(function(){
pausedText.destroy();
this.game.paused = false;
}, this);
},

update: function () {

}
};

Platformer.platform = {
createPlatform: function (game) {
var posX = Math.floor(Math.random() * Platformer.GAME_WIDTH * this._numberOfPlatforms * 70);
var posY = Math.floor(Math.random() * Platformer.GAME_HEIGHT * this._numberOfPlatforms * 50);
var platform = game.add.sprite(posX, posY, 'platform');


game._platforms.add(platform);
platform.events.onOutOfBounds.add(this.removePlatform, this);
},

removePlatform: function (game) {
this._platform.kill();
}

}

I can get it to work to place them randomly, but the idea of a platformer should be you could actually jump on it... With enough distance but not too much, so I guess not entirely random.

Hope you have some ideas!

Thanks in advance.

[lewster32]

This example has a routine for placing objects randomly on a grid (which you'll want for platforms no doubt): http://examples.phaser.io/_site/view_full.html?d=groups&f=depth+sort.js&t=depth%20sort

[Julia]

But should I be using tilemaps for that example? I prefer not to... If I would do it that way, would I be able to jump on them or would they be completely random and sometimes not reachable?

[lewster32]

No, that example doesn't use tilemaps. As for being able to jump on them, that becomes a more difficult problem - my approach there would be to start at the player's starting point, and place a platform randomly within a certain distance of the player (the distance being how far they can jump) and then keep going, placing the next platform within a certain distance of the last. You'd also want to influence the overall direction otherwise you'd just end up with a cloud of platforms around your player, so you'd maybe want to bias the platforms to always be above or to the right of the previous platform.