Added region-stepped origin.

scripts/origin/region_transform.gd

@@ -0,0 +1,36 @@
+class_name RegionTransform
+extends Node
+
+@export var offset: Vector3
+@export var region: Vector3i
+@export var target: Node3D
+
+func _enter_tree() -> void:
+    if not target:
+        target = get_parent()
+    RegionOrigin.add_node(target)
+
+func _exit_tree() -> void:
+    RegionOrigin.remove_node(target)
+
+func move_offset(delta_offset: Vector3) -> void:
+    set_offset(offset + delta_offset)
+
+func set_offset(new_offset: Vector3) -> void:
+    offset = new_offset
+    var delta_sector: Vector3i = _floor_ftoi(new_offset / 1000.0)
+    region += delta_sector
+    offset -= Vector3(delta_sector) * 1000.0
+    sync_to_transform()
+
+func altitude() -> float:
+    return offset.y + float(region.y) * 1000.0
+
+func sync_to_transform() -> void:
+    target.transform.origin = offset + Vector3(region - RegionOrigin.origin)
+
+func sync_from_transform() -> void:
+    set_offset(target.transform.origin)
+
+static func _floor_ftoi(vec: Vector3) -> Vector3i:
+    return Vector3i(int(floorf(vec.x)), int(floorf(vec.y)), int(floorf(vec.z)))