feat(foliage): add recovering grass trails and bush contact

world/jajce/GrassInteractionController.gd

@@ -7,14 +7,40 @@ const CLEARING_LIMIT := 4
 @export_range(1, SHADER_INTERACTOR_LIMIT, 1) var max_interactors := 8
 @export_range(0.02, 0.5, 0.01) var update_interval := 0.08
 @export var path_clearings: Array[NodePath] = []
+@export var actor_root_path := NodePath("../../..")
+@export var foliage_root_path := NodePath("../..")
+@export var simulation_manager_path := NodePath("../../../SimulationManager")
+@export var primary_interactor_path := NodePath("../../../Player")
 
 var _elapsed := 0.0
+var _trail_map := FoliageTrailMap.new()
 
 
 func _ready() -> void:
 	# JajceWorld first isolates its mutable materials in the parent's _ready().
-	call_deferred("_configure_path_clearings")
-	_refresh_interactors()
+	call_deferred("_configure_interaction")
+
+
+func _configure_interaction() -> void:
+	_configure_path_clearings()
+	var simulation := get_node_or_null(simulation_manager_path)
+	if simulation != null and simulation.has_signal("state_restored"):
+		simulation.connect("state_restored", reset_interaction)
+	if is_processing():
+		_refresh_interactors(0.0)
+
+
+func set_interaction_enabled(enabled: bool) -> void:
+	set_process(enabled)
+	reset_interaction()
+	_elapsed = update_interval
+
+
+func reset_interaction() -> void:
+	_trail_map.clear()
+	if grass_material != null:
+		grass_material.set_shader_parameter("interactor_count", 0)
+	_bind_trail_materials(false)
 
 
 func _configure_path_clearings() -> void:
@@ -44,35 +70,76 @@ func _process(delta: float) -> void:
 	_elapsed += delta
 	if _elapsed < update_interval:
 		return
+	_refresh_interactors(_elapsed)
 	_elapsed = 0.0
-	_refresh_interactors()
 
 
-func _refresh_interactors() -> void:
+func _refresh_interactors(delta: float = 0.08) -> void:
 	if grass_material == null:
 		return
 	var camera := get_viewport().get_camera_3d()
 	var origin := camera.global_position if camera != null else Vector3.ZERO
+	var actor_root := get_node_or_null(actor_root_path)
+	var primary := get_node_or_null(primary_interactor_path)
 	var nearest: Array[Node3D] = []
+	var limit := clampi(max_interactors, 1, SHADER_INTERACTOR_LIMIT)
 	for value in get_tree().get_nodes_in_group("grass_interactors"):
 		var candidate := value as Node3D
-		if candidate == null:
+		if (
+			candidate == null
+			or candidate.is_queued_for_deletion()
+			or not candidate.is_visible_in_tree()
+			or candidate.get_viewport() != get_viewport()
+			or (actor_root != null and not actor_root.is_ancestor_of(candidate))
+		):
 			continue
 		var insert_at := nearest.size()
 		var candidate_distance := origin.distance_squared_to(candidate.global_position)
 		for index in nearest.size():
-			if candidate_distance < origin.distance_squared_to(nearest[index].global_position):
+			if (
+				candidate == primary
+				or (
+					nearest[index] != primary
+					and (
+						candidate_distance
+						< origin.distance_squared_to(nearest[index].global_position)
+					)
+				)
+			):
 				insert_at = index
 				break
 		nearest.insert(insert_at, candidate)
-		if nearest.size() > max_interactors:
+		if nearest.size() > limit:
 			nearest.pop_back()
 
 	var positions := PackedVector3Array()
 	positions.resize(SHADER_INTERACTOR_LIMIT)
 	for index in SHADER_INTERACTOR_LIMIT:
 		positions[index] = Vector3(0.0, -1000.0, 0.0)
+	var trail_positions: Dictionary[int, Vector3] = {}
 	for index in nearest.size():
 		positions[index] = nearest[index].global_position
+		trail_positions[nearest[index].get_instance_id()] = positions[index]
 	grass_material.set_shader_parameter("interactor_count", nearest.size())
 	grass_material.set_shader_parameter("interactor_positions", positions)
+	_trail_map.advance(delta, origin, trail_positions)
+	_bind_trail_materials(true)
+
+
+func _bind_trail_materials(enabled: bool) -> void:
+	if grass_material != null:
+		grass_material.set_shader_parameter("foliage_trail_map", _trail_map.texture)
+		grass_material.set_shader_parameter("foliage_trail_rect", _trail_map.world_rect)
+		grass_material.set_shader_parameter("foliage_trails_enabled", enabled)
+	var foliage_root := get_node_or_null(foliage_root_path)
+	if foliage_root == null:
+		return
+	for value in get_tree().get_nodes_in_group("interactive_foliage"):
+		var patch := value as StylizedBerryPatch
+		if patch != null and foliage_root.is_ancestor_of(patch):
+			patch.set_contact_field(_trail_map.texture, _trail_map.world_rect, enabled)
+			if grass_material != null:
+				patch.set_contact_actors(
+					grass_material.get_shader_parameter("interactor_positions"),
+					int(grass_material.get_shader_parameter("interactor_count")) if enabled else 0
+				)