phaser/src/gameobjects/components/ScrollFactor.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 getting and setting the Scroll Factor of a Game Object.
 *
 * @name Phaser.GameObjects.Components.ScrollFactor
 * @since 3.0.0
 */

var ScrollFactor = {

    /**
     * The horizontal scroll factor of this Game Object.
     *
     * The scroll factor controls the influence of the movement of a Camera upon this Game Object.
     *
     * When a camera scrolls it will change the location at which this Game Object is rendered on-screen.
     * It does not change the Game Objects actual position values.
     *
     * A value of 1 means it will move exactly in sync with a camera.
     * A value of 0 means it will not move at all, even if the camera moves.
     * Other values control the degree to which the camera movement is mapped to this Game Object.
     * 
     * Please be aware that scroll factor values other than 1 are not taken in to consideration when
     * calculating physics collisions. Bodies always collide based on their world position, but changing
     * the scroll factor is a visual adjustment to where the textures are rendered, which can offset
     * them from physics bodies if not accounted for in your code.
     *
     * @name Phaser.GameObjects.Components.ScrollFactor#scrollFactorX
     * @type {number}
     * @default 1
     * @since 3.0.0
     */
    scrollFactorX: 1,

    /**
     * The vertical scroll factor of this Game Object.
     *
     * The scroll factor controls the influence of the movement of a Camera upon this Game Object.
     *
     * When a camera scrolls it will change the location at which this Game Object is rendered on-screen.
     * It does not change the Game Objects actual position values.
     *
     * A value of 1 means it will move exactly in sync with a camera.
     * A value of 0 means it will not move at all, even if the camera moves.
     * Other values control the degree to which the camera movement is mapped to this Game Object.
     * 
     * Please be aware that scroll factor values other than 1 are not taken in to consideration when
     * calculating physics collisions. Bodies always collide based on their world position, but changing
     * the scroll factor is a visual adjustment to where the textures are rendered, which can offset
     * them from physics bodies if not accounted for in your code.
     *
     * @name Phaser.GameObjects.Components.ScrollFactor#scrollFactorY
     * @type {number}
     * @default 1
     * @since 3.0.0
     */
    scrollFactorY: 1,

    /**
     * Sets the scroll factor of this Game Object.
     *
     * The scroll factor controls the influence of the movement of a Camera upon this Game Object.
     *
     * When a camera scrolls it will change the location at which this Game Object is rendered on-screen.
     * It does not change the Game Objects actual position values.
     *
     * A value of 1 means it will move exactly in sync with a camera.
     * A value of 0 means it will not move at all, even if the camera moves.
     * Other values control the degree to which the camera movement is mapped to this Game Object.
     * 
     * Please be aware that scroll factor values other than 1 are not taken in to consideration when
     * calculating physics collisions. Bodies always collide based on their world position, but changing
     * the scroll factor is a visual adjustment to where the textures are rendered, which can offset
     * them from physics bodies if not accounted for in your code.
     *
     * @method Phaser.GameObjects.Components.ScrollFactor#setScrollFactor
     * @since 3.0.0
     *
     * @param {number} x - The horizontal scroll factor of this Game Object.
     * @param {number} [y=x] - The vertical scroll factor of this Game Object. If not set it will use the `x` value.
     *
     * @return {this} This Game Object instance.
     */
    setScrollFactor: function (x, y)
    {
        if (y === undefined) { y = x; }

        this.scrollFactorX = x;
        this.scrollFactorY = y;

        return this;
    }

};

module.exports = ScrollFactor;