feat: height map (#458)

api/src/main/java/org/allaymc/api/client/storage/PlayerData.java

@@ -6,7 +6,6 @@
 import org.allaymc.api.server.Server;
 import org.cloudburstmc.nbt.NbtMap;
 import org.joml.Vector3i;
-import org.joml.Vector3ic;
 
 import static org.allaymc.api.utils.AllayNbtUtils.writeVector3f;
 
@@ -17,16 +16,15 @@
 @Setter
 @Builder
 public class PlayerData {
-    // EntityPlayer's NBT which can be generated through method EntityPlayer#saveNBT()
-    protected NbtMap playerNBT;
+    // EntityPlayer's nbt which can be generated through method EntityPlayer#saveNBT()
+    protected NbtMap nbt;
+
     // The following fields are not included in the return object of method EntityPlayer#saveNBT()
-    protected String currentWorldName;
-    protected int currentDimensionId;
-    // Can be null
-    protected Vector3ic spawnPoint;
-    // Can be null
-    protected String spawnPointWorldName;
-    protected int spawnPointDimensionId;
+    // We should store the world and dimension information of the player
+    // because the player data is not stored in chunk like other entities.
+    // Without these information, we can't know which world and dimension the player is in.
+    protected String world;
+    protected int dimension;
 
     public static PlayerData createEmpty() {
         var server = Server.getInstance();
@@ -36,43 +34,25 @@ public static PlayerData createEmpty() {
         var worldName = globalSpawnPoint.dimension().getWorld().getWorldData().getName();
         var dimId = globalSpawnPoint.dimension().getDimensionInfo().dimensionId();
         return builder()
-                .playerNBT(builder.build())
-                .currentWorldName(worldName)
-                .currentDimensionId(dimId)
-                .spawnPoint(globalSpawnPoint)
-                .spawnPointWorldName(worldName)
-                .spawnPointDimensionId(dimId)
+                .nbt(builder.build())
+                .world(worldName)
+                .dimension(dimId)
                 .build();
     }
 
     public static PlayerData fromNBT(NbtMap nbt) {
         var builder = builder();
-        builder.playerNBT(nbt.getCompound("PlayerNBT"))
-                .currentWorldName(nbt.getString("CurrentWorldName"))
-                .currentDimensionId(nbt.getInt("CurrentDimensionId"));
-        if (nbt.containsKey("SpawnPointX")) {
-            int spx = nbt.getInt("SpawnPointX");
-            int spy = nbt.getInt("SpawnPointY");
-            int spz = nbt.getInt("SpawnPointZ");
-            builder.spawnPoint(new Vector3i(spx, spy, spz))
-                    .spawnPointWorldName(nbt.getString("SpawnPointWorldName"))
-                    .spawnPointDimensionId(nbt.getInt("SpawnPointDimensionId"));
-        }
+        builder.nbt(nbt.getCompound("NBT"))
+                .world(nbt.getString("World"))
+                .dimension(nbt.getInt("Dimension"));
         return builder.build();
     }
 
     public NbtMap toNBT() {
         var builder = NbtMap.builder()
-                .putCompound("PlayerNBT", playerNBT)
-                .putString("CurrentWorldName", currentWorldName)
-                .putInt("CurrentDimensionId", currentDimensionId);
-        if (spawnPoint != null) {
-            builder.putInt("SpawnPointX", spawnPoint.x())
-                    .putInt("SpawnPointY", spawnPoint.y())
-                    .putInt("SpawnPointZ", spawnPoint.z())
-                    .putString("SpawnPointWorldName", spawnPointWorldName)
-                    .putInt("SpawnPointDimensionId", spawnPointDimensionId);
-        }
+                .putCompound("NBT", nbt)
+                .putString("World", world)
+                .putInt("Dimension", dimension);
         return builder.build();
     }
 }

api/src/main/java/org/allaymc/api/entity/component/EntityBaseComponent.java

@@ -14,6 +14,7 @@
 import org.allaymc.api.entity.type.EntityType;
 import org.allaymc.api.item.ItemStack;
 import org.allaymc.api.math.location.Location3fc;
+import org.allaymc.api.math.position.Position3ic;
 import org.allaymc.api.utils.MathUtils;
 import org.allaymc.api.world.Dimension;
 import org.allaymc.api.world.World;
@@ -851,4 +852,27 @@ default BlockState getBlockStateStandingOn() {
         if (currentBlockState != air) return currentBlockState;
         else return getDimension().getBlockState(loc.x(), loc.y() - 1, loc.z());
     }
+
+    default boolean canStandSafely(Position3ic pos) {
+        return canStandSafely(pos.x(), pos.y(), pos.z(), getDimension());
+    }
+
+    /**
+     * Check if the specified position is a safe standing position.
+     *
+     * @param x the x coordinate.
+     * @param y the y coordinate.
+     * @param z the z coordinate.
+     *
+     * @return {@code true} if the specified position is a safe standing position, otherwise {@code false}.
+     */
+    default boolean canStandSafely(int x, int y, int z, Dimension dimension) {
+        var blockUnder = dimension.getBlockState(x, y - 1, z);
+        var blockTypeUnder = blockUnder.getBlockType();
+        if (!blockTypeUnder.getMaterial().isSolid()) {
+            return false;
+        }
+        return dimension.getBlockState(x, y, z).getBlockType() == BlockTypes.AIR &&
+               dimension.getBlockState(x, y + 1, z).getBlockType() == BlockTypes.AIR;
+    }
 }

api/src/main/java/org/allaymc/api/server/ServerSettings.java

@@ -141,13 +141,19 @@ public static class WorldConfig extends OkaeriConfig {
         @CustomKey("chunk-sending-strategy")
         private ChunkSendingStrategy chunkSendingStrategy = ChunkSendingStrategy.ASYNC;
 
-        @CustomKey("do-first-spawn-chunk-threshold")
-        private int doFirstSpawnChunkThreshold = 56;
+        @CustomKey("fully-join-chunk-threshold")
+        private int fullyJoinChunkThreshold = 56;
 
         @Comment("Determines how long a chunk without chunk loaders will remain loaded (gt)")
         @CustomKey("remove-unneeded-chunk-cycle")
         private int removeUnneededChunkCycle = 1200;
 
+        @Comment("If set to true, the server will load chunks around the spawn point")
+        @Comment("Which will reduce the time on joining server")
+        @Comment("However, this will increase the server's memory usage")
+        @CustomKey("load-spawn-point-chunks")
+        private boolean loadSpawnPointChunks = true;
+
         public enum ChunkSendingStrategy {
             ASYNC,
             SYNC

api/src/main/java/org/allaymc/api/utils/AllayNbtUtils.java

@@ -5,10 +5,7 @@
 import org.cloudburstmc.nbt.NBTOutputStream;
 import org.cloudburstmc.nbt.NbtMap;
 import org.cloudburstmc.nbt.NbtMapBuilder;
-import org.joml.Vector2f;
-import org.joml.Vector2fc;
-import org.joml.Vector3f;
-import org.joml.Vector3fc;
+import org.joml.*;
 
 import java.io.ByteArrayInputStream;
 import java.io.ByteArrayOutputStream;
@@ -109,6 +106,40 @@ public static void writeVector3f(NbtMapBuilder nbt, String rootName, String f1,
         nbt.putCompound(rootName, pos);
     }
 
+    /**
+     * Read a vector3 from NBT.
+     *
+     * @param nbt the NBT map.
+     * @param rootName the root name.
+     * @param f1 the x field.
+     * @param f2 the y field.
+     * @param f3 the z field.
+     * @return the vector3.
+     */
+    public static Vector3i readVector3i(NbtMap nbt, String rootName, String f1, String f2, String f3) {
+        var pos = nbt.getCompound(rootName);
+        return new Vector3i(pos.getInt(f1), pos.getInt(f2), pos.getInt(f3));
+    }
+
+    /**
+     * Write a vector3 to NBT.
+     *
+     * @param nbt the NBT builder.
+     * @param rootName the root name.
+     * @param f1 the x field.
+     * @param f2 the y field.
+     * @param f3 the z field.
+     * @param vector3i the vector3.
+     */
+    public static void writeVector3i(NbtMapBuilder nbt, String rootName, String f1, String f2, String f3, Vector3ic vector3i) {
+        var pos = NbtMap.builder()
+                .putInt(f1, vector3i.x())
+                .putInt(f2, vector3i.y())
+                .putInt(f3, vector3i.z())
+                .build();
+        nbt.putCompound(rootName, pos);
+    }
+
     /**
      * Read a vector2 from NBT.
      *

api/src/main/java/org/allaymc/api/world/Dimension.java

@@ -1,6 +1,5 @@
 package org.allaymc.api.world;
 
-import com.google.common.base.Function;
 import com.google.common.base.Preconditions;
 import it.unimi.dsi.fastutil.longs.Long2ObjectOpenHashMap;
 import org.allaymc.api.block.data.BlockFace;
@@ -16,6 +15,7 @@
 import org.allaymc.api.entity.type.EntityTypes;
 import org.allaymc.api.item.ItemStack;
 import org.allaymc.api.math.position.Position3i;
+import org.allaymc.api.math.position.Position3ic;
 import org.allaymc.api.utils.MathUtils;
 import org.allaymc.api.utils.Utils;
 import org.allaymc.api.world.generator.WorldGenerator;
@@ -30,6 +30,7 @@
 import org.cloudburstmc.protocol.bedrock.data.ParticleType;
 import org.cloudburstmc.protocol.bedrock.data.SoundEvent;
 import org.cloudburstmc.protocol.bedrock.packet.*;
+import org.jetbrains.annotations.Range;
 import org.jetbrains.annotations.Unmodifiable;
 import org.jetbrains.annotations.UnmodifiableView;
 import org.joml.Vector3fc;
@@ -38,6 +39,7 @@
 
 import java.util.*;
 import java.util.concurrent.ThreadLocalRandom;
+import java.util.function.Predicate;
 
 import static org.allaymc.api.block.type.BlockTypes.AIR;
 
@@ -910,4 +912,59 @@ default void breakBlock(Vector3ic pos, ItemStack usedItem, EntityPlayer player)
      * @return Whether the block is successfully broken.
      */
     boolean breakBlock(int x, int y, int z, ItemStack usedItem, EntityPlayer player);
+
+    /**
+     * Get the height of the highest non-air block at the specified x and z coordinates.
+     * <p>
+     * Please note that this method will load the chunk if it's not loaded.
+     *
+     * @param x the x coordinate.
+     * @param z the z coordinate.
+     *
+     * @return the height of the highest non-air block at the specified x and z coordinates.
+     */
+    default int getHeight(int x, int z) {
+        var chunk = getChunkService().getChunkByDimensionPos(x, z);
+        if (chunk == null) chunk = getChunkService().getOrLoadChunkSync(x >> 4, z >> 4);
+        return chunk.getHeight(x & 15, z & 15);
+    }
+
+    /**
+     * Get the highest block at the specified x and z coordinates.
+     *
+     * @param x the x coordinate.
+     * @param z the z coordinate.
+     *
+     * @return the highest blockstate at the specified x and z coordinates.
+     */
+    default BlockState getHighestBlockState(int x, int z) {
+        return getBlockState(x, getHeight(x, z), z);
+    }
+
+    default Vector3ic findSuitableGroundPosAround(Predicate<Position3ic> predicate, int x, int z, @Range(from = 0, to = Integer.MAX_VALUE) int range) {
+        return findSuitableGroundPosAround(predicate, x, z, range, 10);
+    }
+
+    /**
+     * Find a safe standing position around the specified x and z coordinates.
+     *
+     * @param x     the x coordinate.
+     * @param z     the z coordinate.
+     * @param range the range to search.
+     *
+     * @return a safe standing position around the specified x and z coordinates, or {@code null} if not found.
+     */
+    default Vector3ic findSuitableGroundPosAround(Predicate<Position3ic> predicate, int x, int z, @Range(from = 0, to = Integer.MAX_VALUE) int range, @Range(from = 0, to = Integer.MAX_VALUE) int attemptCount) {
+        var rand = ThreadLocalRandom.current();
+        while (attemptCount > 0) {
+            attemptCount--;
+            var px = x + rand.nextInt(-range, range + 1);
+            var pz = z + rand.nextInt(-range, range + 1);
+            var py = getHeight(px, pz) + 1;
+            if (predicate.test(new Position3i(px, py, pz, this))) {
+                return new org.joml.Vector3i(px, py, pz);
+            }
+        }
+        return null;
+    }
 }

api/src/main/java/org/allaymc/api/world/World.java

@@ -20,7 +20,7 @@ public interface World {
      *
      * @return the thread which the world is running on.
      */
-    Thread getThread();
+    Thread getWorldThread();
 
     /**
      * Get the tick of the world.

api/src/main/java/org/allaymc/api/world/WorldData.java

@@ -286,9 +286,6 @@ public <V> V getGameRule(GameRule gameRule) {
         return gameRules.get(gameRule);
     }
 
-    /**
-     * The overworld default spawn point
-     */
     public Vector3ic getSpawnPoint() {
         return spawnPoint;
     }

api/src/main/java/org/allaymc/api/world/chunk/UnsafeChunk.java

@@ -178,16 +178,6 @@ default BlockState getBlockState(@Range(from = 0, to = 15) int x, int y, @Range(
      */
     void setHeight(@Range(from = 0, to = 15) int x, @Range(from = 0, to = 15) int z, int height);
 
-    /**
-     * Get height array.
-     * <p>
-     * Different from getHeight(), all values in the short[] array returned by this method are
-     * greater than or equal to 0 (can be understood as getHeight() - minHeight())
-     *
-     * @return the height array
-     */
-    short[] getHeightArray();
-
     /**
      * Get height of the specified position.
      *

api/src/main/java/org/allaymc/api/world/heightmap/HeightMap.java

@@ -3,6 +3,8 @@
 import lombok.AllArgsConstructor;
 import lombok.Getter;
 
+import java.util.Arrays;
+
 /**
  * HeightMap stores the height of each pos in a chunk.
  *
@@ -14,7 +16,19 @@ public final class HeightMap {
     private final short[] heights;
 
     public HeightMap() {
-        this(new short[256]);
+        this.heights = new short[256];
+        Arrays.fill(this.heights, (short) -1);
+    }
+
+    /**
+     * Compute the index of the specified position.
+     *
+     * @param x the x coordinate of the pos.
+     * @param z the z coordinate of the pos.
+     * @return the index of the pos.
+     */
+    public static int computeIndex(int x, int z) {
+        return (x << 4) | z;
     }
 
     /**
@@ -25,7 +39,17 @@ public HeightMap() {
      * @return the height of the pos.
      */
     public short get(int x, int z) {
-        return heights[(x << 4) | z];
+        return heights[computeIndex(x, z)];
+    }
+
+    /**
+     * Get the height of the specified position.
+     *
+     * @param index the index of the pos.
+     * @return the height of the pos.
+     */
+    public short get(int index) {
+        return heights[index];
     }
 
     /**
@@ -36,7 +60,17 @@ public short get(int x, int z) {
      * @param height the height of the pos.
      */
     public void set(int x, int z, short height) {
-        heights[(x << 4) | z] = height;
+        heights[computeIndex(x, z)] = height;
+    }
+
+    /**
+     * Set the height of the specified position.
+     *
+     * @param index the index of the pos.
+     * @param height the height of the pos.
+     */
+    public void set(int index, short height) {
+        heights[index] = height;
     }
 
     /**