Improve world authoring workflow

world/fishable_water_region.gd

@@ -1,9 +1,38 @@
+@tool
 class_name FishableWaterRegion
 extends Area3D
 
 const FishPoolType = preload("res://fish/fish_pool.gd")
 
+enum SurfaceHeightMode {
+	EXPLICIT,
+	PARENT_GLOBAL_Y,
+}
+
 @export var location_tags: Array[StringName] = []
 @export var fish_pool: FishPoolType
 @export var selection_priority: int = 0
+@export_group("Surface")
+@export var surface_height_mode: SurfaceHeightMode = SurfaceHeightMode.EXPLICIT:
+	set(value):
+		surface_height_mode = value
+		if Engine.is_editor_hint():
+			notify_property_list_changed()
+## Legacy explicit height used when Surface Height Mode is Explicit.
 @export var surface_height: float = 0.3
+
+
+func get_surface_height() -> float:
+	if surface_height_mode == SurfaceHeightMode.PARENT_GLOBAL_Y:
+		var surface_owner := get_parent() as Node3D
+		if surface_owner != null:
+			return surface_owner.global_position.y
+	return surface_height
+
+
+func _validate_property(property: Dictionary) -> void:
+	if (
+		property.name == "surface_height"
+		and surface_height_mode == SurfaceHeightMode.PARENT_GLOBAL_Y
+	):
+		property.usage = int(property.usage) & ~PROPERTY_USAGE_EDITOR