Added region-stepped origin.

demo/demo.gd

@@ -0,0 +1,4 @@
+extends Node3D
+
+func _ready() -> void:
+    RegionOrigin.anchor = $FixedWingAircraft/RegionTransform

demo/demo.gd.uid

@@ -0,0 +1 @@
+uid://cdk7y1rat3juk

demo/demo.tscn

@@ -1,5 +1,6 @@
-[gd_scene load_steps=18 format=3 uid="uid://d20jwlre5rc5m"]
+[gd_scene load_steps=20 format=3 uid="uid://d20jwlre5rc5m"]
 
+[ext_resource type="Script" uid="uid://cdk7y1rat3juk" path="res://demo/demo.gd" id="1_oeqrt"]
 [ext_resource type="Texture2D" uid="uid://bruwqvb6qrsfn" path="res://demo/textures/untexture.png" id="1_ytiva"]
 [ext_resource type="Script" uid="uid://bddnsq0h2tpf" path="res://scripts/aircraft/nodes/fixed_wing_aircraft.gd" id="2_dar0o"]
 [ext_resource type="Resource" uid="uid://dpk3bgq54ajul" path="res://demo/airfoils/symmetric.tres" id="3_u10mr"]
@@ -7,6 +8,7 @@
 [ext_resource type="Resource" uid="uid://p2i7a806s6gs" path="res://demo/propulsion/electric_motor.tres" id="4_s1s6j"]
 [ext_resource type="Script" uid="uid://pc3j1c6e1ra7" path="res://scripts/aircraft/nodes/flight_sim_controller.gd" id="5_s1s6j"]
 [ext_resource type="Script" uid="uid://tgj0rvn5wj8t" path="res://demo/hud.gd" id="6_onu7k"]
+[ext_resource type="Script" uid="uid://ddh4omp23xc58" path="res://scripts/origin/region_transform.gd" id="7_onvmd"]
 
 [sub_resource type="StandardMaterial3D" id="StandardMaterial3D_j5lb4"]
 albedo_texture = ExtResource("1_ytiva")
@@ -14,7 +16,8 @@ uv1_scale = Vector3(100, 100, 100)
 
 [sub_resource type="PlaneMesh" id="PlaneMesh_5hjng"]
 material = SubResource("StandardMaterial3D_j5lb4")
-size = Vector2(2000, 2000)
+size = Vector2(1000, 1000)
+center_offset = Vector3(500, 0, 500)
 
 [sub_resource type="Curve" id="Curve_s1s6j"]
 _limits = [0.0, 0.5, 0.0, 20.0]
@@ -72,6 +75,7 @@ ambient_light_source = 3
 ambient_light_color = Color(1, 1, 1, 1)
 
 [node name="Demo" type="Node3D"]
+script = ExtResource("1_oeqrt")
 
 [node name="Ground" type="MeshInstance3D" parent="."]
 mesh = SubResource("PlaneMesh_5hjng")
@@ -96,6 +100,11 @@ metadata/_custom_type_script = "uid://pc3j1c6e1ra7"
 
 [node name="Camera3D" type="Camera3D" parent="FixedWingAircraft"]
 
+[node name="RegionTransform" type="Node" parent="FixedWingAircraft" node_paths=PackedStringArray("target")]
+script = ExtResource("7_onvmd")
+target = NodePath("..")
+metadata/_custom_type_script = "uid://ddh4omp23xc58"
+
 [node name="CanvasLayer" type="CanvasLayer" parent="."]
 
 [node name="HUD" type="Control" parent="CanvasLayer" node_paths=PackedStringArray("source")]

project.godot

@@ -18,6 +18,7 @@ config/icon="res://icon.svg"
 [autoload]
 
 Atmosphere="*res://scripts/aircraft/nodes/atmosphere.gd"
+RegionOrigin="*res://scripts/origin/region_origin.gd"
 
 [debug]
 

scripts/aircraft/nodes/fixed_wing_aircraft.gd

@@ -17,6 +17,8 @@ var m_relative_velocity: Vector3
 
 var m_is_landed := false
 
+@onready var m_region_transform: RegionTransform = $RegionTransform
+
 func _ready() -> void:
     velocity = -global_basis.z * initial_speed
     m_relative_velocity = transform.basis.inverse() * velocity
@@ -77,6 +79,7 @@ func _physics_process(delta: float) -> void:
         rotate_object_local(steering_axis.normalized(), steering_axis.length())
     
     move_and_slide()
+    m_region_transform.sync_from_transform()
     #if !is_landed:
     #    _fly()
     #else:

scripts/origin/region_origin.gd

@@ -0,0 +1,25 @@
+# no name - meant to be an autoload
+# Handles regional origin.
+extends Node
+
+@export var region_size := 1000.0
+@export var origin := Vector3i.ZERO
+@export var anchor: RegionTransform
+
+var nodes_to_move: Dictionary[Node3D, bool]
+
+func _physics_process(_delta: float) -> void:
+    if (anchor and anchor.region != origin):
+        move_origin(anchor.region)
+
+func add_node(new_node: Node3D) -> void:
+    nodes_to_move[new_node] = true
+
+func remove_node(old_node: Node3D) -> void:
+    nodes_to_move.erase(old_node)
+    
+func move_origin(new_origin: Vector3i) -> void:
+    origin = new_origin
+    var move_amount := Vector3(new_origin - origin * 1000)
+    for node in nodes_to_move:
+        node.transform.origin += move_amount

scripts/origin/region_origin.gd.uid

@@ -0,0 +1 @@
+uid://dlrk82k15q6w3

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)))

scripts/origin/region_transform.gd.uid

@@ -0,0 +1 @@
+uid://ddh4omp23xc58