Phaser Source: src/gameobjects/components/InWorld.js

# Source: src/gameobjects/components/InWorld.js

    /**
    * @author       Richard Davey <rich@photonstorm.com>
    * @copyright    2016 Photon Storm Ltd.
    * @license      {@link https://github.com/photonstorm/phaser/blob/master/license.txt|MIT License}
    */

    /**
    * The InWorld component checks if a Game Object is within the Game World Bounds.
    * An object is considered as being "in bounds" so long as its own bounds intersects at any point with the World bounds.
    * If the AutoCull component is enabled on the Game Object then it will check the Game Object against the Camera bounds as well.
    *
    * @class
    */
    Phaser.Component.InWorld = function () {};

    /**
     * The InWorld component preUpdate handler.
     * Called automatically by the Game Object.
     *
     * @method
     */
    Phaser.Component.InWorld.preUpdate = function () {

        //  Cache the bounds if we need it
        if (this.autoCull || this.checkWorldBounds)
        {
            this._bounds.copyFrom(this.getBounds());

            this._bounds.x += this.game.camera.view.x;
            this._bounds.y += this.game.camera.view.y;

            if (this.autoCull)
            {
                //  Won't get rendered but will still get its transform updated
                if (this.game.world.camera.view.intersects(this._bounds))
                {
                    this.renderable = true;
                    this.game.world.camera.totalInView++;
                }
                else
                {
                    this.renderable = false;

                    if (this.outOfCameraBoundsKill)
                    {
                        this.kill();
                        return false;
                    }
                }
            }

            if (this.checkWorldBounds)
            {
                //  The Sprite is already out of the world bounds, so let's check to see if it has come back again
                if (this._outOfBoundsFired && this.game.world.bounds.intersects(this._bounds))
                {
                    this._outOfBoundsFired = false;
                    this.events.onEnterBounds$dispatch(this);
                }
                else if (!this._outOfBoundsFired && !this.game.world.bounds.intersects(this._bounds))
                {
                    //  The Sprite WAS in the screen, but has now left.
                    this._outOfBoundsFired = true;
                    this.events.onOutOfBounds$dispatch(this);

                    if (this.outOfBoundsKill)
                    {
                        this.kill();
                        return false;
                    }
                }
            }
        }

        return true;

    };

    Phaser.Component.InWorld.prototype = {

        /**
        * If this is set to `true` the Game Object checks if it is within the World bounds each frame.
        *
        * When it is no longer intersecting the world bounds it dispatches the `onOutOfBounds` event.
        *
        * If it was *previously* out of bounds but is now intersecting the world bounds again it dispatches the `onEnterBounds` event.
        *
        * It also optionally kills the Game Object if `outOfBoundsKill` is `true`.
        *
        * When `checkWorldBounds` is enabled it forces the Game Object to calculate its full bounds every frame.
        *
        * This is a relatively expensive operation, especially if enabled on hundreds of Game Objects. So enable it only if you know it's required,
        * or you have tested performance and find it acceptable.
        *
        * @property {boolean} checkWorldBounds
        * @default
        */
        checkWorldBounds: false,

        /**
        * If this and the `checkWorldBounds` property are both set to `true` then the `kill` method is called as soon as `inWorld` returns false.
        *
        * @property {boolean} outOfBoundsKill
        * @default
        */
        outOfBoundsKill: false,

        /**
         * If this and the `autoCull` property are both set to `true`, then the `kill` method
         * is called as soon as the Game Object leaves the camera bounds.
         *
         * @property {boolean} outOfCameraBoundsKill
         * @default
         */
        outOfCameraBoundsKill: false,

        /**
        * @property {boolean} _outOfBoundsFired - Internal state var.
        * @private
        */
        _outOfBoundsFired: false,

        /**
        * Checks if the Game Objects bounds are within, or intersect at any point with the Game World bounds.
        *
        * @property {boolean} inWorld
        * @readonly
        */
        inWorld: {

            get: function () {

                return this.game.world.bounds.intersects(this.getBounds());

            }

        }

    };