hookInput() {
    const cannon = this;

    cc.eventManager.addListener({ // 2
        event: cc.EventListener.KEYBOARD, // 3
        onKeyPressed(kCode, e) { // 4
            switch (kCode) {
                case cc.KEY.a:
                    cannon.angleSpeed = -1 * cannon.baseAngleSpeed;
                    break;
                case cc.KEY.d:
                    cannon.angleSpeed = cannon.baseAngleSpeed;
                    break;
            }
        },
        onKeyReleased(kCode, e) {
            switch (kCode) {
                case cc.KEY.a:
                case cc.KEY.d:
                    cannon.angleSpeed = 0;
                    break;
            }
        }
    }, this.node);
}