fix: center ground under chunks and align player spawn with chunk grid

scripts/server.gd

@@ -213,6 +213,12 @@ func _try_load_real_content() -> Node:
 	marker.position = spawn_pos
 
 	var entries: Array = (index_result.data as Dictionary).get("chunks", [])
+	var min_cx := 0
+	var max_cx := 0
+	var min_cy := 0
+	var max_cy := 0
+	var found_spawn_obj: Variant = null
+
 	for entry in entries:
 		var cx: int = int(entry["cx"])
 		var cy: int = int(entry["cy"])
@@ -229,6 +235,61 @@ func _try_load_real_content() -> Node:
 		_build_chunk_collision(world_root, Vector3i(cx, cy, cz), decoded)
 		_chunks_loaded += 1
 
+		if _chunks_loaded == 1:
+			min_cx = cx
+			max_cx = cx
+			min_cy = cy
+			max_cy = cy
+		else:
+			min_cx = mini(min_cx, cx)
+			max_cx = maxi(max_cx, cx)
+			min_cy = mini(min_cy, cy)
+			max_cy = maxi(max_cy, cy)
+
+		if found_spawn_obj == null:
+			var chunk_origin := Vector3(
+				float(cx * Chunk.CHUNK_SIZE_X),
+				float(cz * Chunk.CHUNK_SIZE_Z),
+				float(cy * Chunk.CHUNK_SIZE_Y)
+			)
+			for obj in decoded.objects:
+				if obj.type == "spawn_point" or str(obj.properties.get("catalog_id", "")) == "spawn_point":
+					found_spawn_obj = chunk_origin + Vector3(obj.position.x, 1.5, obj.position.y)
+					break
+
+	if _chunks_loaded > 0:
+		var props := world_root.find_child("Props", true, false)
+		if props != null:
+			props.queue_free()
+		var chest := world_root.find_child("ScriptedChest", true, false)
+		if chest != null:
+			chest.queue_free()
+
+		var min_x := float(min_cx * Chunk.CHUNK_SIZE_X)
+		var max_x := float((max_cx + 1) * Chunk.CHUNK_SIZE_X)
+		var min_z := float(min_cy * Chunk.CHUNK_SIZE_Y)
+		var max_z := float((max_cy + 1) * Chunk.CHUNK_SIZE_Y)
+		var center_x := (min_x + max_x) * 0.5
+		var center_z := (min_z + max_z) * 0.5
+		var size_x := maxf(40.0, (max_x - min_x) + 8.0)
+		var size_z := maxf(40.0, (max_z - min_z) + 8.0)
+
+		var ground: StaticBody3D = world_root.find_child("Ground", true, false) as StaticBody3D
+		if ground != null:
+			ground.position = Vector3(center_x, -0.5, center_z)
+			var shape_node := ground.find_child("CollisionShape3D", true, false) as CollisionShape3D
+			if shape_node != null:
+				var box := BoxShape3D.new()
+				box.size = Vector3(size_x, 1.0, size_z)
+				shape_node.shape = box
+
+		if found_spawn_obj != null:
+			spawn_pos = found_spawn_obj
+		elif not (room.get("spawn") is Dictionary and (room.get("spawn") as Dictionary).has("pos")):
+			spawn_pos = Vector3(16.0, 1.5, 16.0)
+
+		marker.position = spawn_pos
+
 	return world_root