Geyser/core/src/main/java/org/geysermc/geyser/translator/level/BiomeTranslator.java

/*
 * Copyright (c) 2019-2022 GeyserMC. http://geysermc.org
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 *
 * @author GeyserMC
 * @link https://github.com/GeyserMC/Geyser
 */

package org.geysermc.geyser.translator.level;

import com.github.steveice10.mc.protocol.data.game.RegistryEntry;
import com.github.steveice10.mc.protocol.data.game.chunk.BitStorage;
import com.github.steveice10.mc.protocol.data.game.chunk.DataPalette;
import com.github.steveice10.mc.protocol.data.game.chunk.palette.GlobalPalette;
import com.github.steveice10.mc.protocol.data.game.chunk.palette.Palette;
import com.github.steveice10.mc.protocol.data.game.chunk.palette.SingletonPalette;
import it.unimi.dsi.fastutil.ints.*;
import org.geysermc.geyser.level.chunk.BlockStorage;
import org.geysermc.geyser.level.chunk.bitarray.BitArray;
import org.geysermc.geyser.level.chunk.bitarray.BitArrayVersion;
import org.geysermc.geyser.level.chunk.bitarray.SingletonBitArray;
import org.geysermc.geyser.registry.Registries;
import org.geysermc.geyser.session.GeyserSession;

import java.util.List;

// Array index formula by https://wiki.vg/Chunk_Format
public class BiomeTranslator {

    public static void loadServerBiomes(GeyserSession session, List<RegistryEntry> entries) {
        Int2IntMap biomeTranslations = new Int2IntOpenHashMap();

        int greatestBiomeId = 0;
        for (int i = 0; i < entries.size(); i++) {
            RegistryEntry entry = entries.get(i);
            String javaIdentifier = entry.getId();
            int bedrockId = Registries.BIOME_IDENTIFIERS.get().getOrDefault(javaIdentifier, 0);
            int javaId = i;
            if (javaId > greatestBiomeId) {
                greatestBiomeId = javaId;
            }

            // TODO - the category tag no longer exists - find a better replacement option
//            if (bedrockId == -1) {
//                // There is no matching Bedrock variation for this biome; let's set the closest match based on biome category
//                String category = ((StringTag) ((CompoundTag) biomeTag.get("element")).get("category")).getValue();
//                String replacementBiome = switch (category) {
//                    case "extreme_hills" -> "minecraft:mountains";
//                    case "icy" -> "minecraft:ice_spikes";
//                    case "mesa" -> "minecraft:badlands";
//                    case "mushroom" -> "minecraft:mushroom_fields";
//                    case "nether" -> "minecraft:nether_wastes";
//                    default -> "minecraft:ocean"; // Typically ID 0 so a good default
//                    case "taiga", "jungle", "plains", "savanna", "the_end", "beach", "ocean", "desert", "river", "swamp" -> "minecraft:" + category;
//                };
//                bedrockId = Registries.BIOME_IDENTIFIERS.get().getInt(replacementBiome);
//            }

            // When we see the Java ID, we should instead apply the Bedrock ID
            biomeTranslations.put(javaId, bedrockId);

            if (javaId == 0) {
                // Matches Java behavior when it sees an invalid biome - it just replaces it with ID 0
                biomeTranslations.defaultReturnValue(bedrockId);
            }
        }

        int[] biomes = new int[greatestBiomeId + 1];
        for (Int2IntMap.Entry entry : biomeTranslations.int2IntEntrySet()) {
            biomes[entry.getIntKey()] = entry.getIntValue();
        }
        session.setBiomeTranslations(biomes);
    }

    public static BlockStorage toNewBedrockBiome(GeyserSession session, DataPalette biomeData) {
        int[] biomeTranslations = session.getBiomeTranslations();
        // As of 1.17.10: the client expects the same format as a chunk but filled with biomes
        // As of 1.18 this is the same as Java Edition

        Palette palette = biomeData.getPalette();
        if (palette instanceof SingletonPalette) {
            int biomeId = biomeTranslations[palette.idToState(0)];
            return new BlockStorage(SingletonBitArray.INSTANCE, IntLists.singleton(biomeId));
        } else {
            BlockStorage storage;
            if (!(palette instanceof GlobalPalette)) {
                // Prevent resizing by allocating what we can ahead of time
                BitStorage bitStorage = biomeData.getStorage();
                int size = palette.size();
                BitArray bitArray = BitArrayVersion.forBitsCeil(bitStorage.getBitsPerEntry())
                        .createArray(BlockStorage.SIZE);

                IntList bedrockPalette = new IntArrayList(size);

                for (int i = 0; i < size; i++) {
                    int javaId = palette.idToState(i);
                    bedrockPalette.add(biomeTranslations[javaId]);
                }

                // Each section of biome corresponding to a chunk section contains 4 * 4 * 4 entries
                for (int i = 0; i < 64; i++) {
                    int idx = bitStorage.get(i);
                    int x = i & 3;
                    int y = (i >> 4) & 3;
                    int z = (i >> 2) & 3;
                    // Convert biome coordinates into block coordinates
                    // Bedrock expects a full 4096 blocks
                    multiplyIdToStorage(bitArray, idx, x, y, z);
                }

                storage = new BlockStorage(bitArray, bedrockPalette);
            } else {
                storage = new BlockStorage(0);

                // Each section of biome corresponding to a chunk section contains 4 * 4 * 4 entries
                for (int i = 0; i < 64; i++) {
                    int javaId = palette.idToState(biomeData.getStorage().get(i));
                    int x = i & 3;
                    int y = (i >> 4) & 3;
                    int z = (i >> 2) & 3;
                    // Get the Bedrock biome ID override
                    int biomeId = biomeTranslations[javaId];
                    int idx = storage.idFor(biomeId);
                    // Convert biome coordinates into block coordinates
                    // Bedrock expects a full 4096 blocks
                    // Implementation note: storage.getBitArray() must be called and not stored - if the palette
                    // grows, then the instance can change
                    multiplyIdToStorage(storage.getBitArray(), idx, x, y, z);
                }
            }
            return storage;
        }
    }

    private static void multiplyIdToStorage(final BitArray bitArray, final int idx, final int x, final int y, final int z) {
        for (int blockX = x << 2; blockX < (x << 2) + 4; blockX++) {
            for (int blockZ = z << 2; blockZ < (z << 2) + 4; blockZ++) {
                for (int blockY = y << 2; blockY < (y << 2) + 4; blockY++) {
                    bitArray.set((blockX << 8) | (blockZ << 4) | blockY, idx);
                }
            }
        }
    }
}