DirectionVec.php

<?php
class autowalk extends PluginBase implements Listener{

    public const DISTANCE = 10; 
    public function onEnable(){
        $this->getServer()->getPluginManager()->registerEvents($this,$this);
    }
    public function onMove(PlayerMoveEvent $ev){
        $player = $ev->getPlayer();
        $level = $player->getLevel();

        $x = $player->x + 0.3;
        $y = $player->y + $player->eyeHeight;
        $z = $player->z + 0.3;

        $radYaw = deg2rad(-$player->yaw);
        $radPitch = deg2rad(-$player->pitch);

        $vecX = self::DISTANCE * sin($radYaw);
        $vecY = self::DISTANCE * sin($radPitch);
        $vecZ = self::DISTANCE * cos($radYaw);

        $block = Block::get(1);
        $level->setBlock(new Vector3($x + $vecX, $y + $vecY, $z + $vecZ), $block);

    }
}