Godot-RTS-Template/core/scripts/player_selection_manager.gd

extends Control
class_name SelectionManager

var selecting:=false
var drag_start: Vector2
var select_box: Rect2
@onready var box_color: Color = ProjectSettings.get_setting("game/interface/selection_rectangle_color",Color("#00ff0066"))
@onready var box_color_outline: Color = ProjectSettings.get_setting("game/interface/selection_rectangle_color_outline",Color("#00ff00"))

@onready var optimized_rect:bool = ProjectSettings.get_setting("game/interface/optimized_rectangle",false)
@export var rect_style: StyleBoxFlat
@onready var cam = get_viewport().get_camera_3d()


func _ready() -> void:
	if optimized_rect:return


func _unhandled_input(e: InputEvent) -> void:
	if e is InputEventMouseButton and e.button_index == MOUSE_BUTTON_LEFT:
		if e.pressed:
			selecting = true
			drag_start = e.position
		else: # when button is released
			selecting = false
			if drag_start.is_equal_approx(e.position):
				select_box = Rect2(e.position, Vector2.ZERO) # when just clicked
				print("one click")

			queue_redraw()

		update_selected_units()
	elif selecting and e is InputEventMouseMotion:
		var x_min = min(drag_start.x, e.position.x)
		var y_min = min(drag_start.y, e.position.y)
		select_box = Rect2(x_min,y_min,
			max(drag_start.x,e.position.x) - x_min,
			max(drag_start.y,e.position.y) - y_min)

		update_selected_units()
		queue_redraw()


func check_raycast(mouse_pos:Vector2,collision_mask:int=4294967295) -> Dictionary:
	var from = cam.project_ray_origin(mouse_pos)
	var to = from + cam.project_ray_normal(mouse_pos) * 1000 #Magic number
	var query = PhysicsRayQueryParameters3D.new()
	query.from = from ; query.to = to
	query.collision_mask = collision_mask
	var space_state = cam.get_world_3d().direct_space_state
	return space_state.intersect_ray(query)


#HACK :https://www.youtube.com/watch?v=NxW9t-YgJkM
func update_selected_units() -> void:
	var units_array = get_tree().get_nodes_in_group('selectable-entity')
	var raycast = check_raycast(get_local_mouse_position(),2)
	for entity: Entity in units_array: #TODO: currently searching in all unit in the world.  Should search in spawned in the chunk
		if entity.is_in_selection(select_box, cam):
			entity.select()
		elif entity.is_under_mouse(raycast):
			entity.select()
		else:
			entity.deselect()


func _draw() -> void:
	if not selecting:return
	if select_box and rect_style:
		if optimized_rect:
			draw_rect(select_box,box_color)
			draw_rect(select_box,box_color_outline,false,2.0,true)
		elif rect_style:
			draw_style_box(rect_style,select_box)