pocketmine\block\Liquid::getFlowVector PHP Method

    public function getFlowVector()
    {
        $vector = new Vector3(0, 0, 0);
        if ($this->temporalVector === null) {
            $this->temporalVector = new Vector3(0, 0, 0);
        }
        $decay = $this->getEffectiveFlowDecay($this);
        for ($j = 0; $j < 4; ++$j) {
            $x = $this->x;
            $y = $this->y;
            $z = $this->z;
            if ($j === 0) {
                --$x;
            } elseif ($j === 1) {
                ++$x;
            } elseif ($j === 2) {
                --$z;
            } elseif ($j === 3) {
                ++$z;
            }
            $sideBlock = $this->getLevel()->getBlock($this->temporalVector->setComponents($x, $y, $z));
            $blockDecay = $this->getEffectiveFlowDecay($sideBlock);
            if ($blockDecay < 0) {
                if (!$sideBlock->canBeFlowedInto()) {
                    continue;
                }
                $blockDecay = $this->getEffectiveFlowDecay($this->getLevel()->getBlock($this->temporalVector->setComponents($x, $y - 1, $z)));
                if ($blockDecay >= 0) {
                    $realDecay = $blockDecay - ($decay - 8);
                    $vector->x += ($sideBlock->x - $this->x) * $realDecay;
                    $vector->y += ($sideBlock->y - $this->y) * $realDecay;
                    $vector->z += ($sideBlock->z - $this->z) * $realDecay;
                }
                continue;
            } else {
                $realDecay = $blockDecay - $decay;
                $vector->x += ($sideBlock->x - $this->x) * $realDecay;
                $vector->y += ($sideBlock->y - $this->y) * $realDecay;
                $vector->z += ($sideBlock->z - $this->z) * $realDecay;
            }
        }
        if ($this->getDamage() >= 8) {
            $falling = false;
            if (!$this->getLevel()->getBlock($this->temporalVector->setComponents($this->x, $this->y, $this->z - 1))->canBeFlowedInto()) {
                $falling = true;
            } elseif (!$this->getLevel()->getBlock($this->temporalVector->setComponents($this->x, $this->y, $this->z + 1))->canBeFlowedInto()) {
                $falling = true;
            } elseif (!$this->getLevel()->getBlock($this->temporalVector->setComponents($this->x - 1, $this->y, $this->z))->canBeFlowedInto()) {
                $falling = true;
            } elseif (!$this->getLevel()->getBlock($this->temporalVector->setComponents($this->x + 1, $this->y, $this->z))->canBeFlowedInto()) {
                $falling = true;
            } elseif (!$this->getLevel()->getBlock($this->temporalVector->setComponents($this->x, $this->y + 1, $this->z - 1))->canBeFlowedInto()) {
                $falling = true;
            } elseif (!$this->getLevel()->getBlock($this->temporalVector->setComponents($this->x, $this->y + 1, $this->z + 1))->canBeFlowedInto()) {
                $falling = true;
            } elseif (!$this->getLevel()->getBlock($this->temporalVector->setComponents($this->x - 1, $this->y + 1, $this->z))->canBeFlowedInto()) {
                $falling = true;
            } elseif (!$this->getLevel()->getBlock($this->temporalVector->setComponents($this->x + 1, $this->y + 1, $this->z))->canBeFlowedInto()) {
                $falling = true;
            }
            if ($falling) {
                $vector = $vector->normalize()->add(0, -6, 0);
            }
        }
        return $vector->normalize();
    }