text: class Help extends BaseMenu {
  
    setup() {
      this.activeItem = 0;
      this.mainMenu.push(
        new MenuItem('The Basic Idea', true, 
          () => manager.showScene(Info, { topic: Info.IDEA_P1 }) )
      );
      this.mainMenu.push(
        new MenuItem('How to play as Gunner', false, 
          () => manager.showScene(Info, { topic: Info.GUNNER_P1 }) )
      );
      this.mainMenu.push(
        new MenuItem('How to play as Engineer', false, 
        () => manager.showScene(Info, { topic: Info.ENGINEER_P1 }) )
      );
      this.mainMenu.push(
        new MenuItem('How to play as Wing Commander', false, 
        () => manager.showScene(Info, { topic: Info.COMMANDER_P1 }) )
      );
      this.mainMenu.push(
        new MenuItem('Back to Main Menu', false, 
          () => manager.showScene(Menu) )
      );
      this.drawIconFunctions = [
        () => this.bg.showBuilding(width/2 - 50, 150), 
        () => this.gunner.show(), 
        () => this.roller.show(), 
        () => this.sam.show(), 
        this.drawMainMenuIcon
      ];
    }
  
    enter() {
      if (this.sceneArgs) {
        this.activeItem = this.sceneArgs.index;
        this.updateMenu();
      }
      this.bg = new AirBaseBG();
      this.gunner = GOFactory.FACTORY.getAntiAircraftGun(width/2, 175, false);
      this.roller = GOFactory.FACTORY.getRoadRoller(width/2, 170, false);
      this.sam = GOFactory.FACTORY.getSAM(width/2, 170, false);
      this.sam.loadMissiles();
    }
  
    draw() {
      background(bgColor);
      super.draw();
      this.drawIconFunctions[this.activeItem]();
    }
  
    drawMainMenuIcon() {
      stroke(lineColor);
      strokeWeight(1);
      fill(lineColor);
      rect (width/2 - 50, 120, 100, 8);
      rect (width/2 - 50, 150, 100, 8);
      rect (width/2 - 50, 180, 100, 8);
    }
  
  }