Initial commit

Scenes/Scripts/sun_imposter.gd

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+extends Node3D
+## Keep the sun disc inside the cockpit far plane. Aim SunLight.
+## Never leave the disc sitting on the Moon.
+
+@export var sun_disc_path: NodePath = ^"SunDisc"
+@export var sun_light_path: NodePath = ^"../SunLight"
+@export var sun_direction: Vector3 = Vector3(-0.82, 0.45, 0.35)
+@export var visual_distance: float = 220000.0
+@export var visual_radius: float = 9000.0
+
+var _mesh: MeshInstance3D
+var _light: DirectionalLight3D
+var _base_radius: float = 0.5
+
+
+func _ready() -> void:
+	_mesh = get_node_or_null(sun_disc_path) as MeshInstance3D
+	if _mesh == null:
+		_mesh = find_child("SunDisc", true, false) as MeshInstance3D
+	if _mesh and _mesh.mesh is SphereMesh:
+		_base_radius = maxf((_mesh.mesh as SphereMesh).radius, 0.5)
+	_light = get_node_or_null(sun_light_path) as DirectionalLight3D
+	if _light == null:
+		_light = get_node_or_null("../SunLight") as DirectionalLight3D
+	sun_direction = sun_direction.normalized()
+	_aim_light()
+	set_process(true)
+
+
+func _aim_light() -> void:
+	if _light == null:
+		return
+	var target: Vector3 = _light.global_position - sun_direction
+	if target.is_equal_approx(_light.global_position):
+		return
+	_light.look_at(target, Vector3.UP)
+
+
+func _process(_delta: float) -> void:
+	if _mesh == null:
+		return
+	var viewer: Node3D = FloatingOrigin.focus
+	var origin: Vector3 = viewer.global_position if viewer and is_instance_valid(viewer) else global_position
+	_mesh.global_position = origin + sun_direction * visual_distance
+	_mesh.scale = Vector3.ONE * (visual_radius / _base_radius)
+	_mesh.visible = true
+	_aim_light()