Implement Caves

[VixikHD]

Since I found cave part generated already, I am reporting this too.
With spectator mode I cannot find any caves in the underground.

[Muqsit]

This project is a port of GlowstoneMC's world generator which doesn't support caves yet. Once GlowstoneMC adds support for it, I'll happily port it. I don't expect GlowstoneMC to work on it anytime soon, but feel free to maintain a customized fork of this project.

[Muqsit]

Looks like GlowstoneMC's work on world generation is stalled. If anyone knows of any open-source cave generators or reference to them, do let me know (PRs are welcome too).

[ShockedPlot7560]

Hi @Muqsit
I was recently looking to make my vanilla generator to improve the world generation.
So I was looking to implement the caves after making the surface, logical. And I remember I found this java edition plugin that implements a carver in it.
I was looking for the principle of minecraft caves at the time and it seems to me that they implement it correctly.
Hopefully it will help.

[TheShermanTanker]

In my survival plugin I use an extremely badly ported version of the vanilla Java 1.12 cave generator. The caves that it generates are extremely poor quality, even for pre 1.17 standards, and there are some obfuscated parameters and locals that I never managed to figure out proper names for, but I figured it might still help this project somewhat to study it. Maybe someone who knows more than me could improve it to at least be able to generate proper pre 1.17 caves? Either way, here it is:

<?php

namespace me\theshermantanker\server\generation\populator;

use pocketmine\block\VanillaBlocks;
use pocketmine\data\bedrock\BiomeIds;
use pocketmine\utils\Random;
use pocketmine\world\ChunkManager;
use pocketmine\world\generator\populator\Populator;

final class Cave implements Populator {

    public function populate(ChunkManager $level, int $chunkX, int $chunkZ, Random $random) : void {
        $rand = clone $random;
        $xMultiplier = $rand->nextInt();
        $zMultiplier = $rand->nextInt();

        for ($x = $chunkX - 8; $x <= $chunkX + 8; $x += 1)  {
            for ($z = $chunkZ - 8; $z <= $chunkZ + 8; $z += 1) {
                $seedX = $x * $xMultiplier;
                $seedZ = $z * $zMultiplier;
                $rand->setSeed($seedX ^ $seedZ ^ $random->getSeed());
                $this->makeCave($level, $x, $z, $chunkX, $chunkZ, $rand);
            }
        }
    }

    private function makeCave(ChunkManager $level, int $chunkX, int $chunkZ, int $initialX, int $initialZ, Random $random) : void {
        $count = $random->nextBoundedInt($random->nextBoundedInt($random->nextBoundedInt(15) + 1) + 1);

        if ($random->nextBoundedInt(7) !== 0) {
            $count = 0;
        }

        for ($index = 0; $index < $count; $index += 1) {
            $x = floatval($chunkX * 16 + $random->nextBoundedInt(16));
            $y = $random->nextBoundedInt($random->nextBoundedInt(120) + 8);
            $z = $chunkZ * 16 + $random->nextBoundedInt(16);
            $innerCount = 1;

            if ($random->nextBoundedInt(4) == 0) {
                $this->addRoom($random->nextInt(), $initialX, $initialZ, $level, $x, $y, $z, $random);
                $innerCount += $random->nextBoundedInt(4);
            }

            for ($innerIndex = 0; $innerIndex < $innerCount; $innerIndex += 1) {
                $f = $random->nextFloat() * (M_PI * 2);
                $f1 = ($random->nextFloat() - 0.5) * 2.0 / 8.0;
                $f2 = $random->nextFloat() * 2.0 + $random->nextFloat();
                
                if ($random->nextBoundedInt(10) == 0) {
                    $f2 *= $random->nextFloat() * $random->nextFloat() * 3.0 + 1.0;
                }

                $this->addTunnel($random->nextInt(), $initialX, $initialZ, $level, $x, $y, $z, $f2, $f, $f1, 0, 0, 1.0);
            }
        }
    }

    private function addRoom(int $randSeed, int $initialX, int $initialZ, ChunkManager $level, float $x, float $y, float $z, Random $random) : void {
        $this->addTunnel($randSeed, $initialX, $initialZ, $level, $x, $y, $z, 1.0 + $random->nextFloat() * 6.0, 0.0, 0.0, -1, -1, 0.5);
    }
    
    private function addTunnel(int $randSeed, int $initialX, int $initialZ, ChunkManager $level, float $x, float $y, float $z, float $p_180702_12_, float $p_180702_13_, float $p_180702_14_, int $p_180702_15_, int $p_180702_16_, float $p_180702_17_) : void {
        $chunk = $level->getChunk($initialX, $initialZ);
        $d0 = floatval($initialX * 16 + 8);
        $d1 = floatval($initialZ * 16 + 8);
        $f = 0.0;
        $f1 = 0.0;
        $random = new Random($randSeed);
        
        if ($p_180702_16_ <= 0) {
            $i = 8 * 16 - 16;
            $p_180702_16_ = $i - $random->nextBoundedInt(intval($i / 4));
        }
        
        $flag2 = false;
        
        if ($p_180702_15_ == -1) {
            $p_180702_15_ = $p_180702_16_ / 2;
            $flag2 = true;
        }
        
        $j = $random->nextBoundedInt(intval($p_180702_16_ / 2)) + $p_180702_16_ / 4;
        
        for ($flag = $random->nextBoundedInt(6) == 0; $p_180702_15_ < $p_180702_16_; $p_180702_15_ += 1) {
            $d2 = 1.5 + sin(floatval($p_180702_15_) * M_PI / floatval($p_180702_16_)) * $p_180702_12_;
            $d3 = $d2 * $p_180702_17_;
            $f2 = cos($p_180702_14_);
            $f3 = sin($p_180702_14_);
            $x += cos($p_180702_13_) * $f2;
            $y += $f3;
            $z += sin($p_180702_13_) * $f2;
            
            if ($flag) {
                $p_180702_14_ = $p_180702_14_ * 0.92;
            } else {
                $p_180702_14_ = $p_180702_14_ * 0.7;
            }

            $p_180702_14_ = $p_180702_14_ + $f1 * 0.1;
            $p_180702_13_ += $f * 0.1;
            $f1 = $f1 * 0.9;
            $f = $f * 0.75;
            $f1 = $f1 + ($random->nextFloat() - $random->nextFloat()) * $random->nextFloat() * 2.0;
            $f = $f + ($random->nextFloat() - $random->nextFloat()) * $random->nextFloat() * 4.0;
            
            if (!$flag2 && $p_180702_15_ == $j && $p_180702_12_ > 1.0 && $p_180702_16_ > 0) {
                $this->addTunnel($random->nextInt(), $initialX, $initialZ, $level, $x, $y, $z, $random->nextFloat() * 0.5 + 0.5, $p_180702_13_ - (M_PI / 2), $p_180702_14_ / 3.0, $p_180702_15_, $p_180702_16_, 1.0);
                $this->addTunnel($random->nextInt(), $initialX, $initialZ, $level, $x, $y, $z, $random->nextFloat() * 0.5 + 0.5, $p_180702_13_ + (M_PI / 2), $p_180702_14_ / 3.0, $p_180702_15_, $p_180702_16_, 1.0);
                return;
            }
            
            if ($flag2 || $random->nextBoundedInt(4) !== 0) {
                $d4 = $x - $d0;
                $d5 = $z - $d1;
                $d6 = floatval($p_180702_16_ - $p_180702_15_);
                $d7 = $p_180702_12_ + 2.0 + 16.0;
                
                if ($d4 * $d4 + $d5 * $d5 - $d6 * $d6 > $d7 * $d7) {
                    return;
                }
                
                if ($x >= $d0 - 16.0 - $d2 * 2.0 && $z >= $d1 - 16.0 - $d2 * 2.0 && $x <= $d0 + 16.0 + $d2 * 2.0 && $z <= $d1 + 16.0 + $d2 * 2.0) {
                    $initialRelativeX = floor($x - $d2) - $initialX * 16 - 1;
                    $maxRelativeX = floor($x + $d2) - $initialX * 16 + 1;
                    $minRelativeY = floor($y - $d3) - 1;
                    $topY = floor($y + $d3) + 1;
                    $initialRelativeZ = floor($z - $d2) - $initialZ * 16 - 1;
                    $maxRelativeZ = floor($z + $d2) - $initialZ * 16 + 1;
                    
                    if ($initialRelativeX < 0) {
                        $initialRelativeX = 0;
                    }
                    
                    if ($maxRelativeX > 16) {
                        $maxRelativeX = 16;
                    }
                    
                    if ($minRelativeY < 1) {
                        $minRelativeY = 1;
                    }
                    
                    if ($topY > 248) {
                        $topY = 248;
                    }
                    
                    if ($initialRelativeZ < 0) {
                        $initialRelativeZ = 0;
                    }
                    
                    if ($maxRelativeZ > 16) {
                        $maxRelativeZ = 16;
                    }
                    
                    $encounteredWater = false;
                    
                    for ($relativeX = $initialRelativeX; !$encounteredWater && $relativeX < $maxRelativeX; $relativeX += 1) {
                        for ($relativeZ = $initialRelativeZ; !$encounteredWater && $relativeZ < $maxRelativeZ; $relativeZ += 1) {
                            for ($relativeY = $topY + 1; !$encounteredWater && $relativeY >= $minRelativeY - 1; $relativeY -= 1) {
                                if ($relativeY >= 0 && $relativeY < 256) {
                                    if ($chunk->getBlockStateId($relativeX, $relativeY, $relativeZ) === VanillaBlocks::WATER()->getStateId() /* TODO How to check for flowing water? */) {
                                        $encounteredWater = true;
                                    }
                                    
                                    if ($relativeY != $minRelativeY - 1 && $relativeX != $initialRelativeX && $relativeX != $maxRelativeX - 1 && $relativeZ != $initialRelativeZ && $relativeZ != $maxRelativeZ - 1) {
                                        $relativeY = $minRelativeY;
                                    }
                                }
                            }
                        }
                    }

                    if (!$encounteredWater) {
                        for ($relX = $initialRelativeX; $relX < $maxRelativeX; $relX += 1) {
                            $d10 = (floatval($relX + $initialX * 16) + 0.5 - $x) / $d2;

                            for ($relZ = $initialRelativeZ; $relZ < $maxRelativeZ; $relZ += 1) {
                                $d8 = (floatval($relZ + $initialZ * 16) + 0.5 - $z) / $d2;
                                $encounteredGrass = false;

                                if ($d10 * $d10 + $d8 * $d8 < 1.0) {
                                    for ($relY = $topY; $relY > $minRelativeY; $relY -= 1) {
                                        $d9 = (floatval($relY - 1) + 0.5 - $y) / $d3;

                                        if ($d9 > -0.7 && $d10 * $d10 + $d9 * $d9 + $d8 * $d8 < 1.0) {
                                            $state = $chunk->getBlockStateId($relX, $relY, $relZ);
                                            $above = $chunk->getBlockStateId($relX, $relY + 1, $relZ);

                                            if ($state === VanillaBlocks::GRASS() || $state === VanillaBlocks::MYCELIUM()) {
                                                $encounteredGrass = true;
                                            }

                                            if ($this->canReplaceBlock($state, $above)) {
                                                if ($relY - 1 < 10) {
                                                    $chunk->setBlockStateId($relX, $relY, $relZ, VanillaBlocks::LAVA()->getStateId());
                                                } else {
                                                    $chunk->setBlockStateId($relX, $relY, $relZ, VanillaBlocks::AIR()->getStateId());
                                                    
                                                    if ($encounteredGrass && $chunk->getBlockStateId($relX, $relY - 1, $relZ) === VanillaBlocks::DIRT()) {
                                                        $chunk->setBlockStateId($relX, $relY - 1, $relZ, $chunk->getBiomeId($relX, 0, $relZ) === BiomeIds::DESERT ? VanillaBlocks::SAND()->getStateId() : VanillaBlocks::GRASS()->getStateId());
                                                    }
                                                }
                                            }
                                        }
                                    }
                                }
                            }
                        }
                        
                        if ($flag2) {
                            break;
                        }
                    }
                }
            }
        }
    }
    
    private function canReplaceBlock(int $id, int $above) : bool {
        if ($id == VanillaBlocks::STONE()->getStateId()) {
            return true;
        } else if ($id === VanillaBLocks::DIRT()->getStateId()) {
            return true;
        } else if ($id === VanillaBlocks::GRASS()->getStateId()) {
            return true;
        } else if ($id === VanillaBLocks::HARDENED_CLAY()->getStateId()) {
            return true;
        } else if ($id === VanillaBlocks::STAINED_CLAY()->getStateId()) {
            return true;
        }  else if ($id === VanillaBlocks::SANDSTONE()->getStateId()) {
            return true;
        } else if ($id === VanillaBlocks::RED_SANDSTONE()->getStateId()) {
            return true;
        } else if ($id === VanillaBlocks::MYCELIUM()->getStateId()) {
            return true;
        } else if ($id === VanillaBlocks::SNOW_LAYER()->getStateId()) {
            return true;
        } else {
            return ($id === VanillaBlocks::SAND()->getStateId() || $id === VanillaBlocks::GRAVEL()->getStateId()) && $above !== VanillaBlocks::WATER()->getStateId();
        }
    }
}

?>