function FSM() {var activeState = null;//@param state {Function} 每一个状态对应一个执行函数this.setState = function(state) {activeState = state;};this.update = function() {if (activeState != null) {activeState();}};
}var f = new FSM();
var flag = true;f.setState(function() {console.log('现在是站立状态');
});//模拟状态切换
(function updateState() {if (flag) {f.setState(function() {console.log('现在是移动状态');});flag = !flag;} else {f.setState(function() {console.log('现在是站立状态');});flag = !flag;}f.update();setTimeout(updateState, 1000);
})();

update(dt) {switch (state) {case STATE.IDLE:    //空闲this.updateIdle(dt);break;case STATE.WALKING:    //移动this.updateWalking(dt);break;case STATE.JUMPING:    //跳跃this.updateJumping(dt);break;case STATE.DASHING:    //冲刺this.updateDashing(dt);break;case STATE.DASHING_JUMPING:   //冲刺跳this.updateDashingJumping(dt);break;}
}

//空闲
updateIdle(dt) {this.speed.x = 0;    //处于静止状态，速度为0if (key[65]) { //向左移动this.speed.x -= this.speedX;this.direction = -1;this.state = STATE.WALKING; //进入移动状态this.play();  //播放移动状态时的动画
    }if (key[68]) { //向右移动this.speed.x += this.speedX;this.direction = 1;this.state = STATE.WALKING;//同上this.play();}if (key[75]) { //跳跃if (!this.jumping) { //这里不用判断onGround，因为处于idle状态必然是onGroundthis.state = STATE.JUMPING;//进入跳跃状态this.jumping = true;this.speed.y = this.jumpSpeed;}}if (key[85]) { //冲刺if (!this.dashing) {this.dashLifeTime = CONFIG.MAX_DASH_LIFE_TIME;this.state = STATE.DASHING;//进入冲刺状态this.dashing = true;this.speed.x += CONFIG.DASH_SPEED * this.direction;}} else {this.dashing = false;}this.speed.y += this.gravity;//更新位置this.moveX(dt);this.moveY(dt);if (this.pos.y >= 9.375) {this.speed.y = 0;this.pos.y = 9.375;if (!key[75]) this.jumping = false;}
}

//移动
updateWalking(dt) {this.state = STATE.IDLE;this.speed.x = 0;if (key[65]) {this.speed.x -= this.speedX;this.state = STATE.WALKING;this.direction = -1;}else if (key[68]) {this.speed.x += this.speedX;this.state = STATE.WALKING;this.direction = 1;}if (key[75]) {if (!this.jumping) {this.state = STATE.JUMPING;this.jumping = true;this.speed.y = this.jumpSpeed;}} else {this.jumping = false;}if (key[85]) { //冲刺if (!this.dashing) {this.dashLifeTime = CONFIG.MAX_DASH_LIFE_TIME;this.state = STATE.DASHING;this.dashing = true;this.speed.x += CONFIG.DASH_SPEED * this.direction;}} else {this.dashing = false;}this.moveX(dt);this.moveY(dt);if (this.state === STATE.IDLE) this.play();
}