shaku/src/input/gamepad.js

A simple and effective JavaScript game development framework that knows its place!

/**
 * Define a gamepad object.
 * 
 * |-- copyright and license --|
 * @module     Shaku
 * @file       shaku\src\input\gamepad.js
 * @author     Ronen Ness (ronenness@gmail.com | http://ronenness.com)
 * @copyright  (c) 2021 Ronen Ness
 * @license    MIT
 * |-- end copyright and license --|
 * 
 */
'use strict';
const Vector2 = require("../utils/vector2");


/**
 * Gamepad data object.
 * This object represents a snapshot of a gamepad state, it does not update automatically.
 */
class Gamepad
{
    /**
     * Create gamepad state object.
     * @param {*} gp Browser gamepad state object.
     */
    constructor(gp)
    {
        /**
         * Gamepad Id.
         * @name Gamepad#id
         * @type {String}
         */
        this.id = gp.id;

        // set buttons down state
        this._buttonsDown = [];
        for (let i = 0; i < gp.buttons.length; ++i) {
            this._buttonsDown[i] = _gamepadButtonPressed(gp.buttons[i]);
        }

        /**
         * Gamepad first axis value.
         * @name Gamepad#axis1
         * @type {Vector2}
         */
        this.axis1 = new Vector2(gp.axes[0], gp.axes[1]);

        /**
         * Gamepad second axis value.
         * @name Gamepad#axis2
         * @type {Vector2}
         */
        this.axis2 = new Vector2(gp.axes[2] || 0, gp.axes[3] || 0);

        /**
         * Mapping type.
         * @name Gamepad#mapping
         * @type {String}
         */
        this.mapping = gp.mapping;

        /**
         * True if the gamepad is of a known type and we have extra mapped attributes.
         * False if unknown / not supported.
         * @name Gamepad#isMapped
         * @type {Boolean}
         */
        this.isMapped = false;

        // standard mapping
        if (this.mapping === "standard") {

            /**
             * Gamepad left stick.
             * Only available with "standard" mapping.
             * @name Gamepad#leftStick
             * @type {Vector2}
             */
            this.leftStick = this.axis1;

            /**
             * Gamepad right stick.
             * Only available with "standard" mapping.
             * @name Gamepad#rightStick
             * @type {Vector2}
             */
            this.rightStick = this.axis2;

            /**
             * Gamepad left stick is pressed.
             * Only available with "standard" mapping.
             * @name Gamepad#leftStickPressed
             * @type {Boolean}
             */
            this.leftStickPressed = this._buttonsDown[10];

            /**
             * Gamepad right stick is pressed.
             * Only available with "standard" mapping.
             * @name Gamepad#leftStickPressed
             * @type {Boolean}
             */
            this.rightStickPressed = this._buttonsDown[11];

            /**
             * Right cluster button states.
             * @name Gamepad#rightButtons
             * @type {FourButtonsCluster}
             */
            this.rightButtons = new FourButtonsCluster(this._buttonsDown[0], this._buttonsDown[1], this._buttonsDown[2], this._buttonsDown[3]);

            /**
             * Left cluster button states.
             * @name Gamepad#leftButtons
             * @type {FourButtonsCluster}
             */
            this.leftButtons = new FourButtonsCluster(this._buttonsDown[13], this._buttonsDown[15], this._buttonsDown[14], this._buttonsDown[12]);

            /**
             * Center cluster button states.
             * @name Gamepad#leftButtons
             * @type {FourButtonsCluster}
             */
            this.centerButtons = new ThreeButtonsCluster(this._buttonsDown[8], this._buttonsDown[9], this._buttonsDown[16]);

            /**
             * Front buttons states.
             * @name Gamepad#frontButtons
             * @type {FrontButtons}
             */            
            this.frontButtons = new FrontButtons(this._buttonsDown[4], this._buttonsDown[5], this._buttonsDown[6], this._buttonsDown[7]);

            /**
             * True if the gamepad is of a known type and we have extra mapped attributes.
             * False if unknown.
             * @name Gamepad#isMapped
             * @type {Boolean}
             */
            this.isMapped = true;
        }

        // freeze self
        Object.freeze(this);
    }

    /**
     * Get button state (if pressed down) by index.
     * @param {Number} index Button index to check.
     * @returns {Boolean} True if pressed, false otherwise.
     */
    button(index)
    {
        return this._buttonsDown[index];
    }

    /**
     * Get buttons count.
     * @returns {Number} Buttons count.
     */
    get buttonsCount()
    {
        return this._buttonsDown.length;
    }
}


/**
 * Buttons cluster container - 4 buttons.
 */
class FourButtonsCluster
{
    /**
     * Create the cluster states.
     * @param {Boolean} bottom Bottom button state.
     * @param {Boolean} right Right button state.
     * @param {Boolean} left Left button state.
     * @param {Boolean} top Top button state.
     */
    constructor(bottom, right, left, top)
    {
        this.bottom = Boolean(bottom);
        this.right = Boolean(right);
        this.left = Boolean(left);
        this.top = Boolean(top);
    }
}


/**
 * Buttons cluster container - 3 buttons.
 */
class ThreeButtonsCluster
{
    /**
     * Create the cluster states.
     * @param {Boolean} left Left button state.
     * @param {Boolean} right Right button state.
     * @param {Boolean} center Center button state.
     */
    constructor(left, right, center)
    {
        this.left = Boolean(left);
        this.right = Boolean(right);
        this.center = Boolean(center);
    }
}


/**
 * Front buttons.
 */
class FrontButtons
{
    /**
     * Create the cluster states.
     */
    constructor(topLeft, topRight, bottomLeft, bottomRight)
    {
        this.topLeft = Boolean(topLeft);
        this.topRight = Boolean(topRight);
        this.bottomLeft = Boolean(bottomLeft);
        this.bottomRight = Boolean(bottomRight);
    }
}


/**
 * Get if a gamepad button is currently pressed.
 * @prviate
 */
function _gamepadButtonPressed(b) 
{
    if (typeof b === "object") {
    return b.pressed;
    }
    return b === 1.0;
}


// export the gamepad data
module.exports = Gamepad;