pocketmine\entity\Zombie::onUpdate PHP Method

    public function onUpdate($currentTick)
    {
        if ($this->closed !== false) {
            return false;
        }
        return parent::onUpdate($currentTick);
        $this->lastUpdate = $currentTick;
        $this->timings->startTiming();
        $hasUpdate = parent::onUpdate($currentTick);
        if ($this->isAlive()) {
            /* Don't use time directly
             * Instead, get remainder of current time divided by 24,000
             * This tells us the time of day, which is what we really need
             */
            $timeOfDay = abs($this->getLevel()->getTime() % 24000);
            if (0 < $timeOfDay and $timeOfDay < 13000) {
                $this->setOnFire(2);
            }
            //僵尸起火
            $p = $this->getNearestPlayer();
            //找到最近的可以被仇恨的玩家
            if (!$p) {
                $this->hated = false;
                if (++$this->moveTicker >= 100) {
                    $this->moveDirection = $this->generateRandomDirection();
                    $this->moveTicker = 0;
                }
            } else {
                $this->hated = $p;
                if ($p->distance($this) <= $this->fire_r) {
                    $p->setOnFire(2);
                }
                //点燃玩家
                if (!$this->tempTicking) {
                    if (++$this->hateTicker >= 10 or $this->moveDirection == null) {
                        //每0.5秒获取僵尸前进的新方向
                        $this->moveDirection = $this->generateDirection($p);
                        $this->hateTicker = 0;
                    }
                }
            }
            if ($this->tempTicking) {
                //帮助僵尸寻找新的方向走出困境
                if (++$this->tempTicker >= 20) {
                    $this->tempTicking = false;
                    $this->tempTicker = 0;
                }
            }
            if ($this->hated instanceof Player) {
                //攻击玩家
                if ($this->hated->distance($this) < $this->attack_r) {
                    $this->hated->attack(2, new EntityDamageByEntityEvent($this, $this->hated, EntityDamageEvent::CAUSE_ENTITY_ATTACK, 2));
                }
            }
            if ($this->moveDirection != null) {
                if ($this->motionX ** 2 + $this->motionZ ** 2 <= $this->moveDirection->lengthSquared()) {
                    $motionY = $this->getVelY();
                    //僵尸运动计算
                    if ($motionY >= 0) {
                        $this->motionX = $this->moveDirection->x * $this->moveSpeed;
                        $this->motionZ = $this->moveDirection->z * $this->moveSpeed;
                        $this->motionY = $motionY;
                    } else {
                        $this->moveDirection = $this->generateRandomDirection();
                        //生成随机运动方向
                        $this->moveTicker = 0;
                        $this->tempTicking = true;
                    }
                }
            } else {
                $this->moveDirection = $this->generateRandomDirection();
                $this->moveTicker = 0;
            }
            //var_dump($this->moveDirection,$this->motionX,$this->motionZ);
            $expectedPos = new Vector3($this->x + $this->motionX, $this->y + $this->motionY, $this->z + $this->motionZ);
            if ($this->motionY == 0) {
                $this->motionY -= $this->gravity;
            }
            //重力计算
            $this->move($this->motionX, $this->motionY, $this->motionZ);
            if ($expectedPos->distanceSquared($this) > 0) {
                $this->moveDirection = $this->generateRandomDirection();
            }
            $friction = 1 - $this->drag;
            $this->motionX *= $friction;
            //$this->motionY *= 1 - $this->drag;
            $this->motionZ *= $friction;
            $f = sqrt($this->motionX ** 2 + $this->motionZ ** 2);
            $this->yaw = -atan2($this->motionX, $this->motionZ) * 180 / M_PI;
            //视角计算
            //$this->pitch = (-atan2($f, $this->motionY) * 180 / M_PI);
            $this->updateMovement();
        }
        $this->timings->stopTiming();
        return $hasUpdate or !$this->onGround or abs($this->motionX) > 1.0E-5 or abs($this->motionY) > 1.0E-5 or abs($this->motionZ) > 1.0E-5;
    }