phaser/examples/physics/quadtree - ids.js

var game = new Phaser.Game(800, 600, Phaser.CANVAS, 'phaser-example', { preload: preload, create: create, update: update, render: render });

function preload() {
    game.load.image('ship', 'assets/sprites/xenon2_ship.png');
    game.load.image('baddie', 'assets/sprites/space-baddie.png');
}

var ship;
var total;
var aliens;

function create() {

    game.world.setBounds(0,0,2000, 2000);

    aliens = [];

    for (var i = 0; i < 1000; i++)
    {
        var s = game.add.sprite(game.world.randomX, game.world.randomY, 'baddie');
        s.name = 'alien' + s;
        s.body.collideWorldBounds = true;
        s.body.bounce.setTo(1, 1);
        s.body.velocity.setTo(10 + Math.random() * 10, 10 + Math.random() * 10);
        aliens.push(s);
    }

    ship = game.add.sprite(400, 400, 'ship');
    ship.body.collideWorldBounds = true;
    ship.body.bounce.setTo(0.5, 0.5);

}

function update() {

    for (var i = 0; i < aliens.length; i++)
    {
        aliens[i].alpha = 0.3;
    }

    total = game.physics.quadTree.retrieve(ship);

    //  Get the ships top-most ID. If the length of that ID is 1 then we can ignore every other result, 
    //  it's simply not colliding with anything :)

    for (var i = 0; i < total.length; i++)
    {
        total[i].sprite.alpha = 1;
    }

    if (game.input.keyboard.isDown(Phaser.Keyboard.LEFT))
    {
        ship.body.velocity.x -= 2;
    }
    else if (game.input.keyboard.isDown(Phaser.Keyboard.RIGHT))
    {
        ship.body.velocity.x += 2;
    }

    if (game.input.keyboard.isDown(Phaser.Keyboard.UP))
    {
        ship.body.velocity.y -= 2;
    }
    else if (game.input.keyboard.isDown(Phaser.Keyboard.DOWN))
    {
        ship.body.velocity.y += 2;
    }

}

function render() {

    for (var i = 0; i < aliens.length; i++)
    {
        // game.debug.renderRectangle(aliens[i].bounds);
    }

    game.debug.renderText(total.length, 32, 32);
    game.debug.renderQuadTree(game.physics.quadTree);
    // game.debug.renderRectangle(ship);

    game.debug.renderText('Index: ' + ship.body.quadTreeIndex, 32, 80);
    
    for (var i = 0; i < ship.body.quadTreeIDs.length; i++)
    {
        game.debug.renderText('ID: ' + ship.body.quadTreeIDs[i], 32, 100 + (i * 20));
    }

}