phaser/src/gameobjects/components/Depth.js

/**
 * @author       Richard Davey <rich@photonstorm.com>
 * @copyright    2018 Photon Storm Ltd.
 * @license      {@link https://github.com/photonstorm/phaser/blob/master/license.txt|MIT License}
 */

/**
 * Provides methods used for setting the depth of a Game Object.
 * Should be applied as a mixin and not used directly.
 * 
 * @name Phaser.GameObjects.Components.Depth
 * @since 3.0.0
 */

var Depth = {

    /**
     * Private internal value. Holds the depth of the Game Object.
     * 
     * @name Phaser.GameObjects.Components.Depth#_depth
     * @type {integer}
     * @private
     * @default 0
     * @since 3.0.0
     */
    _depth: 0,

    /**
     * The depth of this Game Object within the Scene.
     * 
     * The depth is also known as the 'z-index' in some environments, and allows you to change the rendering order
     * of Game Objects, without actually moving their position in the display list.
     *
     * The depth starts from zero (the default value) and increases from that point. A Game Object with a higher depth
     * value will always render in front of one with a lower value.
     *
     * Setting the depth will queue a depth sort event within the Scene.
     * 
     * @name Phaser.GameObjects.Components.Depth#depth
     * @type {number}
     * @since 3.0.0
     */
    depth: {

        get: function ()
        {
            return this._depth;
        },

        set: function (value)
        {
            this.scene.sys.queueDepthSort();
            this._depth = value;
        }

    },

    /**
     * The depth of this Game Object within the Scene.
     * 
     * The depth is also known as the 'z-index' in some environments, and allows you to change the rendering order
     * of Game Objects, without actually moving their position in the display list.
     *
     * The depth starts from zero (the default value) and increases from that point. A Game Object with a higher depth
     * value will always render in front of one with a lower value.
     *
     * Setting the depth will queue a depth sort event within the Scene.
     * 
     * @method Phaser.GameObjects.Components.Depth#setDepth
     * @since 3.0.0
     *
     * @param {integer} value - The depth of this Game Object.
     * 
     * @return {this} This Game Object instance.
     */
    setDepth: function (value)
    {
        if (value === undefined) { value = 0; }

        this.depth = value;

        return this;
    }

};

module.exports = Depth;