Add an option to WorldCreator to avoid spawn location computation on world creation (#13407)

Author: Owen1212055

paper-api/src/main/java/org/bukkit/WorldCreator.java

@@ -2,6 +2,7 @@
 
 import com.google.common.base.Preconditions;
 import java.util.Random;
+import io.papermc.paper.math.Position;
 import org.bukkit.command.CommandSender;
 import org.bukkit.generator.BiomeProvider;
 import org.bukkit.generator.ChunkGenerator;
@@ -26,6 +27,10 @@ public class WorldCreator {
     private boolean hardcore = false;
     private boolean bonusChest = false;
 
+    private @Nullable Position spawnPositionOverride;
+    private @Nullable Float spawnYawOverride;
+    private @Nullable Float spawnPitchOverride;
+
     /**
      * Creates an empty WorldCreationOptions for the given world name.
      *
@@ -261,6 +266,80 @@ public WorldCreator type(@NotNull WorldType type) {
         return this;
     }
 
+    /**
+     * Sets the forced spawn position for the world created by this {@link WorldCreator}.
+     * <p>
+     * This overrides vanilla and custom generator behavior without loading any chunks.
+     * When a forced spawn is specified, the bonus chest will not be generated.
+     *
+     * @param position the spawn position
+     * @param yaw      the yaw rotation at spawn
+     * @param pitch    the pitch rotation at spawn
+     * @return this object, for chaining
+     */
+    @NotNull
+    public WorldCreator forcedSpawnPosition(@NotNull Position position, float yaw, float pitch) {
+        this.spawnPositionOverride = position; // If you set this to null, it wont do anything!
+        this.spawnYawOverride = yaw;
+        this.spawnPitchOverride = pitch;
+        return this;
+    }
+
+    /**
+     * Clears any previously forced spawn position.
+     * <p>
+     * After calling this, vanilla spawn selection behavior is used.
+     *
+     * @return this object, for chaining
+     */
+    @NotNull
+    public WorldCreator clearForcedSpawnPosition() {
+        this.spawnPositionOverride = null;
+        this.spawnYawOverride = null;
+        this.spawnPitchOverride = null;
+        return this;
+    }
+
+    /**
+     * Gets the forced spawn position that will be applied when this world is created.
+     * <p>
+     * If this returns {@code null}, vanilla or custom generator behavior will be used
+     * to determine the spawn position.
+     *
+     * @return the forced spawn position, or {@code null} for the vanilla behavior
+     */
+    public @Nullable Position forcedSpawnPosition() {
+        return this.spawnPositionOverride;
+    }
+
+    /**
+     * Gets the forced spawn yaw that will be applied when this world is created.
+     * <p>
+     * If this returns {@code null}, the spawn yaw will be determined by vanilla behavior
+     * or the world generator.
+     * <p>
+     * This value is only meaningful if a forced spawn position is present.
+     *
+     * @return the forced spawn yaw, or {@code null} for the vanilla behavior
+     */
+    public @Nullable Float forcedSpawnYaw() {
+        return this.spawnYawOverride;
+    }
+
+    /**
+     * Gets the forced spawn pitch that will be applied when this world is created.
+     * <p>
+     * If this returns {@code null}, the spawn pitch will be determined by vanilla behavior
+     * or the world generator.
+     * <p>
+     * This value is only meaningful if a forced spawn position is present.
+     *
+     * @return the forced spawn pitch, or {@code null} for the vanilla behavior
+     */
+    public @Nullable Float forcedSpawnPitch() {
+        return this.spawnPitchOverride;
+    }
+
     /**
      * Gets the generator that will be used to create or load the world.
      * <p>

paper-server/patches/sources/net/minecraft/server/MinecraftServer.java.patch

@@ -300,7 +300,7 @@
          if (profiledDuration != null) {
              profiledDuration.finish(true);
          }
-@@ -422,33 +_,140 @@
+@@ -422,33 +_,150 @@
          }
      }
 
@@ -430,9 +430,9 @@
 +            );
 +        }
 +        this.addLevel(serverLevel);
-+        this.initWorld(serverLevel);
++        this.initWorld(serverLevel, null);
 +    }
-+    public void initWorld(ServerLevel overworld) {
++    public void initWorld(ServerLevel overworld, org.bukkit.@Nullable WorldCreator worldCreator) {
 +        final net.minecraft.world.level.storage.ServerLevelData levelData = overworld.serverLevelData;
 +        final WorldOptions worldOptions = overworld.worldGenSettings.options();
 +        final boolean isDebug = this.worldData.isDebugWorld();
@@ -447,7 +447,17 @@
          if (!levelData.isInitialized()) {
              try {
 -                setInitialSpawn(overworld, levelData, worldOptions.generateBonusChest(), isDebug, this.levelLoadListener);
-+                setInitialSpawn(overworld, levelData, worldOptions.generateBonusChest(), isDebug, overworld.levelLoadListener); // Paper - per world level load listener
++                // Paper start - Allow direct setting spawn location
++                if (worldCreator != null && worldCreator.forcedSpawnPosition() != null) {
++                    levelData.setSpawn(LevelData.RespawnData.of(overworld.dimension(),
++                        io.papermc.paper.util.MCUtil.toBlockPos(worldCreator.forcedSpawnPosition()),
++                        Objects.requireNonNullElse(worldCreator.forcedSpawnYaw(), LevelData.RespawnData.DEFAULT.yaw()),
++                        Objects.requireNonNullElse(worldCreator.forcedSpawnPitch(), LevelData.RespawnData.DEFAULT.pitch())
++                    ));
++                } else {
++                    setInitialSpawn(overworld, levelData, worldOptions.generateBonusChest(), isDebug, overworld.levelLoadListener); // Paper - per world level load listener
++                }
++                // Paper end - Allow direct setting spawn location
                  levelData.setInitialized(true);
                  if (isDebug) {
 -                    this.setupDebugLevel(this.worldData);

paper-server/src/main/java/org/bukkit/craftbukkit/CraftServer.java

@@ -1303,7 +1303,7 @@ public World createWorld(WorldCreator creator) {
         }
 
         this.console.addLevel(serverLevel);
-        this.console.initWorld(serverLevel);
+        this.console.initWorld(serverLevel, creator);
 
         serverLevel.setSpawnSettings(true);