core2d/src/Controller.mjs

Multiplatform 2D interaction engine

"use strict";

import { Command } from "./Command.mjs";

/**
 * Represents a controller, which can be a gamepad or a keyboard.
 */
export class Controller {
  /**
   * Creates a new Controller.
   */
  constructor() {
    /**
     * The tolerance for the command sequence.
     * @type {number}
     */
    this.tolerance = 0;
    this._active = {};
    this._device = null;
    this._hold = {};
    this._sequence = [];
    this._tick = 0;
  }

  /**
   * Checks if a sequence of commands was performed.
   * @param {Command[]} commands The sequence of commands.
   * @returns {boolean} Whether the sequence of commands was performed.
   */
  didPerform(commands) {
    for (let i = 1; i <= commands.length; ++i) {
      if (
        this._sequence[this._sequence.length - i] !=
        commands[commands.length - i]
      ) {
        return false;
      }
    }

    this._sequence = [];
    return true;
  }

  /**
   * Checks if a command is being held down.
   * @param {Command} command The command to check.
   * @returns {boolean} Whether the command is being held down.
   */
  keyDown(command) {
    return this._active[command];
  }

  /**
   * Checks if a command was just pushed.
   * @param {Command} command The command to check.
   * @returns {boolean} Whether the command was just pushed.
   */
  keyPush(command) {
    return this._active[command] && !this._hold[command];
  }

  /**
   * Sets the device of the controller.
   * @param {object} device The device.
   */
  setDevice(device) {
    this._device = device;
  }

  /**
   * Updates the controller.
   */
  update() {
    if (!this._device) {
      return;
    }

    this._hold = {};
    const LAST = this._active;
    this._active = this._device.commands;

    for (let i in this._active) {
      if (LAST[i]) {
        this._hold[i] = true;
      }
    }

    if (this.tolerance && ++this._tick > this.tolerance) {
      this._sequence = [];
      this._tick = 0;
    }

    for (let i in Command) {
      const COMMAND = Command[i];

      if (this.keyPush(COMMAND)) {
        this._sequence.push(COMMAND);
        this._tick = 0;
      }
    }
  }
}