Fire.php

<?php
 
/*
 *
 *  ____            _        _   __  __ _                  __  __ ____
 * |  _ \ ___   ___| | _____| |_|  \/  (_)_ __   ___      |  \/  |  _ \
 * | |_) / _ \ / __| |/ / _ \ __| |\/| | | '_ \ / _ \_____| |\/| | |_) |
 * |  __/ (_) | (__|   <  __/ |_| |  | | | | | |  __/_____| |  | |  __/
 * |_|   \___/ \___|_|\_\___|\__|_|  |_|_|_| |_|\___|     |_|  |_|_|
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * @author PocketMine Team
 * @link http://www.pocketmine.net/
 *
 *
 */
 
declare(strict_types=1);
 
namespace pocketmine\block;
 
use pocketmine\block\utils\Ageable;
use pocketmine\block\utils\AgeableTrait;
use pocketmine\block\utils\BlockEventHelper;
use pocketmine\block\utils\SupportType;
use pocketmine\event\block\BlockBurnEvent;
use pocketmine\math\Facing;
use pocketmine\world\format\Chunk;
use pocketmine\world\World;
use function intdiv;
use function max;
use function min;
use function mt_rand;
 
class Fire extends BaseFire implements Ageable{
    use AgeableTrait;
 
    public const MAX_AGE = 15;
 
    protected function getFireDamage() : int{
        return 1;
    }
 
    private function canBeSupportedBy(Block $block) : bool{
        return $block->getSupportType(Facing::UP) === SupportType::FULL;
    }
 
    public function onNearbyBlockChange() : void{
        $world = $this->position->getWorld();
        $down = $this->getSide(Facing::DOWN);
        if(SoulFire::canBeSupportedBy($down)){
            $world->setBlock($this->position, VanillaBlocks::SOUL_FIRE());
        }elseif(!$this->canBeSupportedBy($this->getSide(Facing::DOWN)) && !$this->hasAdjacentFlammableBlocks()){
            $world->setBlock($this->position, VanillaBlocks::AIR());
        }else{
            $world->scheduleDelayedBlockUpdate($this->position, mt_rand(30, 40));
        }
    }
 
    public function ticksRandomly() : bool{
        return true;
    }
 
    public function onRandomTick() : void{
        $down = $this->getSide(Facing::DOWN);
 
        $result = null;
        if($this->age < self::MAX_AGE && mt_rand(0, 2) === 0){
            $this->age++;
            $result = $this;
        }
        $canSpread = true;
 
        if(!$down->burnsForever()){
            //TODO: check rain
            if($this->age === self::MAX_AGE){
                if(!$down->isFlammable() && mt_rand(0, 3) === 3){ //1/4 chance to extinguish
                    $canSpread = false;
                    $result = VanillaBlocks::AIR();
                }
            }elseif(!$this->hasAdjacentFlammableBlocks()){
                $canSpread = false;
                if($down->isTransparent() || $this->age > 3){
                    $result = VanillaBlocks::AIR();
                }
            }
        }
 
        $world = $this->position->getWorld();
        if($result !== null){
            $world->setBlock($this->position, $result);
        }
 
        $world->scheduleDelayedBlockUpdate($this->position, mt_rand(30, 40));
 
        if($canSpread){
            $this->burnBlocksAround();
            $this->spreadFire();
        }
    }
 
    public function onScheduledUpdate() : void{
        $this->onRandomTick();
    }
 
    private function hasAdjacentFlammableBlocks() : bool{
        foreach(Facing::ALL as $face){
            if($this->getSide($face)->isFlammable()){
                return true;
            }
        }
 
        return false;
    }
 
    private function burnBlocksAround() : void{
        //TODO: raise upper bound for chance in humid biomes
 
        foreach($this->getHorizontalSides() as $side){
            $this->burnBlock($side, 300);
        }
 
        //vanilla uses a 250 upper bound here, but I don't think they intended to increase the chance of incineration
        $this->burnBlock($this->getSide(Facing::UP), 350);
        $this->burnBlock($this->getSide(Facing::DOWN), 350);
    }
 
    private function burnBlock(Block $block, int $chanceBound) : void{
        if(mt_rand(0, $chanceBound) < $block->getFlammability()){
            $cancelled = false;
            if(BlockBurnEvent::hasHandlers()){
                $ev = new BlockBurnEvent($block, $this);
                $ev->call();
                $cancelled = $ev->isCancelled();
            }
            if(!$cancelled){
                $block->onIncinerate();
 
                $world = $this->position->getWorld();
                if($world->getBlock($block->position)->isSameState($block)){
                    $spreadedFire = false;
                    if(mt_rand(0, $this->age + 9) < 5){ //TODO: check rain
                        $fire = clone $this;
                        $fire->age = min(self::MAX_AGE, $fire->age + (mt_rand(0, 4) >> 2));
                        $spreadedFire = $this->spreadBlock($block, $fire);
                    }
                    if(!$spreadedFire){
                        $world->setBlock($block->position, VanillaBlocks::AIR());
                    }
                }
            }
        }
    }
 
    private function spreadFire() : void{
        $world = $this->position->getWorld();
        $difficultyChanceIncrease = $world->getDifficulty() * 7;
        $ageDivisor = $this->age + 30;
 
        for($y = -1; $y <= 4; ++$y){
            $targetY = $y + (int) $this->position->y;
            if($targetY < World::Y_MIN || $targetY >= World::Y_MAX){
                continue;
            }
            //Higher blocks have a lower chance of catching fire
            $randomBound = 100 + ($y > 1 ? ($y - 1) * 100 : 0);
 
            for($z = -1; $z <= 1; ++$z){
                $targetZ = $z + (int) $this->position->z;
                for($x = -1; $x <= 1; ++$x){
                    if($x === 0 && $y === 0 && $z === 0){
                        continue;
                    }
                    $targetX = $x + (int) $this->position->x;
                    if(!$world->isInWorld($targetX, $targetY, $targetZ)){
                        continue;
                    }
 
                    if(!$world->isChunkLoaded($targetX >> Chunk::COORD_BIT_SIZE, $targetZ >> Chunk::COORD_BIT_SIZE)){
                        continue;
                    }
                    $block = $world->getBlockAt($targetX, $targetY, $targetZ);
                    if($block->getTypeId() !== BlockTypeIds::AIR){
                        continue;
                    }
 
                    //TODO: fire can't spread if it's raining in any horizontally adjacent block, or the current one
 
                    $encouragement = 0;
                    foreach($block->position->sides() as $vector3){
                        if($world->isInWorld($vector3->x, $vector3->y, $vector3->z)){
                            $encouragement = max($encouragement, $world->getBlockAt($vector3->x, $vector3->y, $vector3->z)->getFlameEncouragement());
                        }
                    }
 
                    if($encouragement <= 0){
                        continue;
                    }
 
                    $maxChance = intdiv($encouragement + 40 + $difficultyChanceIncrease, $ageDivisor);
                    //TODO: max chance is lowered by half in humid biomes
 
                    if($maxChance > 0 && mt_rand(0, $randomBound - 1) <= $maxChance){
                        $new = clone $this;
                        $new->age = min(self::MAX_AGE, $this->age + (mt_rand(0, 4) >> 2));
                        $this->spreadBlock($block, $new);
                    }
                }
            }
        }
    }
 
    private function spreadBlock(Block $block, Block $newState) : bool{
        return BlockEventHelper::spread($block, $newState, $this);
    }
}