package com.backrooms; import com.mojang.serialization.MapCodec; import com.mojang.serialization.codecs.RecordCodecBuilder; import net.minecraft.block.Block; import net.minecraft.block.BlockState; import net.minecraft.block.Blocks; import net.minecraft.util.math.BlockPos; import net.minecraft.util.math.ChunkPos; import net.minecraft.util.math.MathHelper; import net.minecraft.world.HeightLimitView; import net.minecraft.world.Heightmap; import net.minecraft.world.StructureWorldAccess; import net.minecraft.world.biome.source.BiomeSource; import net.minecraft.world.chunk.Chunk; import net.minecraft.world.gen.GenerationStep; import net.minecraft.world.gen.StructureAccessor; import net.minecraft.world.gen.chunk.ChunkGenerator; import net.minecraft.world.gen.chunk.VerticalBlockSample; import net.minecraft.world.gen.noise.NoiseConfig; import java.util.Arrays; import java.util.List; import java.util.concurrent.CompletableFuture; import java.util.concurrent.Executor; public class BackroomsChunkGenerator extends ChunkGenerator { public static final MapCodec CODEC = RecordCodecBuilder.mapCodec(instance -> instance.group( BiomeSource.CODEC.fieldOf("biome_source").forGetter(g -> g.biomeSource) ).apply(instance, BackroomsChunkGenerator::new)); // Y layout: floor=0, walls/corridors=1-4, ceiling=5 private static final int FLOOR_Y = 0; private static final int CEILING_Y = 5; private static final BlockState FLOOR = Blocks.PODZOL.getDefaultState(); private static final BlockState WALL = Blocks.STRIPPED_BAMBOO_BLOCK.getDefaultState(); private static final BlockState CEILING = Blocks.STRIPPED_JUNGLE_LOG.getDefaultState(); private static final BlockState LAMP = Blocks.SEA_LANTERN.getDefaultState(); private static final BlockState HOLE_EDGE = Blocks.OBSIDIAN.getDefaultState(); private static final BlockState AIR = Blocks.AIR.getDefaultState(); public BackroomsChunkGenerator(BiomeSource biomeSource) { super(biomeSource); } @Override protected MapCodec getCodec() { return CODEC; } @Override public void buildSurface(net.minecraft.world.gen.chunk.ChunkGeneratorSettings settings, StructureAccessor structureAccessor, net.minecraft.registry.RegistryWrapper.WrapperLookup wrapperLookup, NoiseConfig noiseConfig, Chunk chunk) { generateBackrooms(chunk, noiseConfig.getLegacyWorldSeed()); } private void generateBackrooms(Chunk chunk, long seed) { ChunkPos pos = chunk.getPos(); int startX = pos.getStartX(); int startZ = pos.getStartZ(); // Phase 1: base corridor structure for (int lx = 0; lx < 16; lx++) { for (int lz = 0; lz < 16; lz++) { int wx = startX + lx; int wz = startZ + lz; boolean corridor = isInCorridor(wx, wz, seed); // Floor always present chunk.setBlockState(new BlockPos(wx, FLOOR_Y, wz), FLOOR, false); if (corridor) { // Y=1-4 air (default), place ceiling or lamp boolean lamp = isLampPos(wx, wz); chunk.setBlockState(new BlockPos(wx, CEILING_Y, wz), lamp ? LAMP : CEILING, false); } else { // Full wall: Y=1 to CEILING_Y for (int y = 1; y <= CEILING_Y; y++) { chunk.setBlockState(new BlockPos(wx, y, wz), WALL, false); } } } } // Phase 2: rooms (10% per chunk) generateRoom(chunk, pos, seed); // Phase 3: exit blocks (2% per chunk) generateExitBlock(chunk, pos, seed); } private boolean isInCorridor(int wx, int wz, long seed) { // 5-block period: positions [2..4] are corridor, [0..1] are wall int xMod = Math.floorMod(wx, 5); int zMod = Math.floorMod(wz, 5); int xStripIdx = Math.floorDiv(wx, 5); int zStripIdx = Math.floorDiv(wz, 5); int xWidth = corridorWidth(xStripIdx, 0, seed); // 2 or 3 int zWidth = corridorWidth(0, zStripIdx, seed); // Wall zone is first (5 - width) blocks of the period boolean xCorridor = xMod >= (5 - xWidth); boolean zCorridor = zMod >= (5 - zWidth); return xCorridor || zCorridor; } private int corridorWidth(int xi, int zi, long seed) { // 70% = 3 wide, 30% = 2 wide long h = seed ^ (xi * 0x9E3779B97F4A7C15L) ^ (zi * 0x6C62272E07BB0142L); h ^= (h >>> 30); h *= 0xBF58476D1CE4E5B9L; h ^= (h >>> 27); return (Math.abs(h) % 10) < 3 ? 2 : 3; } private boolean isLampPos(int wx, int wz) { return Math.floorMod(wx, 6) == 3 && Math.floorMod(wz, 6) == 3; } private void generateRoom(Chunk chunk, ChunkPos pos, long seed) { int startX = pos.getStartX(); int startZ = pos.getStartZ(); int centerX = startX + 8; int centerZ = startZ + 8; long hash = seed ^ Long.rotateLeft((long) pos.x * 0x9E3779B9L, 17) ^ Long.rotateLeft((long) pos.z * 0xD1B54A32D192ED03L, 31); if (Math.floorMod(Math.abs(hash), 10) != 0) return; // 10% chance int roomSize = ((hash >> 8) & 1L) == 0 ? 12 : 14; int half = roomSize / 2; for (int lx = 0; lx < 16; lx++) { for (int lz = 0; lz < 16; lz++) { int wx = startX + lx; int wz = startZ + lz; int dx = Math.abs(wx - centerX); int dz = Math.abs(wz - centerZ); if (dx > half || dz > half) continue; boolean edge = (dx == half || dz == half); if (edge) { for (int y = 1; y <= CEILING_Y; y++) { chunk.setBlockState(new BlockPos(wx, y, wz), WALL, false); } } else { // Clear walls inside room for (int y = 1; y < CEILING_Y; y++) { chunk.setBlockState(new BlockPos(wx, y, wz), AIR, false); } chunk.setBlockState(new BlockPos(wx, FLOOR_Y, wz), FLOOR, false); chunk.setBlockState(new BlockPos(wx, CEILING_Y, wz), CEILING, false); // Void hole at center (3x3), obsidian ring around it (5x5) if (dx <= 1 && dz <= 1) { // Hole: remove floor → void below chunk.setBlockState(new BlockPos(wx, FLOOR_Y, wz), AIR, false); } else if (dx <= 2 && dz <= 2) { // Obsidian border chunk.setBlockState(new BlockPos(wx, FLOOR_Y, wz), HOLE_EDGE, false); } } } } } private void generateExitBlock(Chunk chunk, ChunkPos pos, long seed) { long hash = seed ^ Long.rotateLeft((long) pos.x * 0x517CC1B727220A95L, 13) ^ Long.rotateLeft((long) pos.z * 0x9E3779B97F4A7C15L, 19); if (Math.floorMod(Math.abs(hash), 50) != 0) return; // 2% chance int startX = pos.getStartX(); int startZ = pos.getStartZ(); // Find first wall-adjacent-to-corridor position in chunk interior for (int lx = 2; lx < 14; lx++) { for (int lz = 2; lz < 14; lz++) { int wx = startX + lx; int wz = startZ + lz; if (!isInCorridor(wx, wz, seed) && (isInCorridor(wx + 1, wz, seed) || isInCorridor(wx - 1, wz, seed) || isInCorridor(wx, wz + 1, seed) || isInCorridor(wx, wz - 1, seed))) { // Place exit block at Y=1 (bottom of wall, reachable) chunk.setBlockState(new BlockPos(wx, 1, wz), BackroomsMod.EXIT_BLOCK.getDefaultState(), false); return; } } } } // ── Required abstract method implementations ────────────────────────────── @Override public CompletableFuture populateNoise(Executor executor, net.minecraft.world.gen.chunk.Blender blender, NoiseConfig noiseConfig, StructureAccessor structureAccessor, Chunk chunk) { return CompletableFuture.completedFuture(chunk); } @Override public void carve(net.minecraft.world.gen.chunk.ChunkGeneratorSettings settings, net.minecraft.registry.RegistryWrapper.WrapperLookup wrapperLookup, net.minecraft.world.biome.BiomeAccess access, StructureAccessor accessor, Chunk chunk, GenerationStep.Carver step, NoiseConfig noiseConfig) { // No carving in the Backrooms } @Override public int getSpawnHeight(HeightLimitView world) { return 1; } @Override public int getSeaLevel() { return -63; } @Override public int getMinimumY() { return 0; } @Override public int getHeight(int x, int z, Heightmap.Type heightmapType, HeightLimitView world, NoiseConfig noiseConfig) { return CEILING_Y + 1; } @Override public VerticalBlockSample getColumnSample(int x, int z, HeightLimitView world, NoiseConfig noiseConfig) { int height = world.getHeight(); BlockState[] states = new BlockState[height]; Arrays.fill(states, AIR); int base = world.getBottomY(); setIfValid(states, FLOOR_Y - base, FLOOR, height); for (int y = 1; y <= CEILING_Y; y++) { setIfValid(states, y - base, isInCorridor(x, z, 0L) ? AIR : WALL, height); } setIfValid(states, CEILING_Y - base, CEILING, height); return new VerticalBlockSample(base, states); } private static void setIfValid(BlockState[] arr, int idx, BlockState state, int len) { if (idx >= 0 && idx < len) arr[idx] = state; } @Override public void getDebugHudText(List text, NoiseConfig noiseConfig, BlockPos pos) { // No debug info needed } @Override public void generateFeatures(StructureWorldAccess world, Chunk chunk, StructureAccessor structureAccessor) { // Features generated in buildSurface } @Override public void populateEntities(net.minecraft.world.ChunkRegion region) { // No entity population } }