A super useful script for fps games. Attach it to the root node in your scene. Provides an FPS counter, fullscreen toggle, exits the game, and reloads the scene.

scene_debug.gd

# Simple Utility Script
# Traps Mouse Cursor and hides it.
# ESCAPE to quit game
# F5 to reload current scene
# F9 to toggle collision shape dispay. Scene MUST be reloaded
# F10 to toggle fps Display
# F11 to switch from windowed to fullscreen
# F12 to take screenshot
#
# Works great for fps games

extends Node

var fpslabel = Label.new()

func _ready():
	# Called when the node is added to the scene for the first time.
	# Initialization here
	get_viewport().size
	self.add_child(fpslabel)
	fpslabel.set_anchors_and_margins_preset(Control.PRESET_TOP_RIGHT)
	fpslabel.margin_left = -40

	var ev = InputEventKey.new()

	ev.scancode = KEY_ESCAPE
	InputMap.add_action("debug_quit")
	InputMap.action_add_event("debug_quit", ev)

	ev = InputEventKey.new()
	ev.scancode = KEY_F5
	InputMap.add_action("debug_reload_scene")
	InputMap.action_add_event("debug_reload_scene", ev)

	ev = InputEventKey.new()
	ev.scancode = KEY_F9
	InputMap.add_action("debug_toggle_collisions")
	InputMap.action_add_event("debug_toggle_collisions", ev)

	ev = InputEventKey.new()
	ev.scancode = KEY_F10
	InputMap.add_action("debug_toggle_fps")
	InputMap.action_add_event("debug_toggle_fps", ev)

	ev = InputEventKey.new()
	ev.scancode = KEY_F11
	InputMap.add_action("debug_toggle_fullscreen")
	InputMap.action_add_event("debug_toggle_fullscreen", ev)

	ev = InputEventKey.new()
	ev.scancode = KEY_F12
	InputMap.add_action("debug_take_screenshot")
	InputMap.action_add_event("debug_take_screenshot", ev)



func _enter_tree():
	Input.set_mouse_mode(Input.MOUSE_MODE_CAPTURED)
	push_warning("WARNING Scene Debug: Be sure to replace this script with proper features")
	print("WARNING Scene Debug: Be sure to replace this script with proper features")

func _exit_tree():
	Input.set_mouse_mode(Input.MOUSE_MODE_VISIBLE)

func _process(delta):
	fpslabel.text= "FPS:" + var2str(Engine.get_frames_per_second())
	fpslabel.margin_left = -fpslabel.rect_size.x


	if Input.is_action_just_pressed("debug_toggle_fps"):
		print("Toggling FPS")
		fpslabel.visible = !fpslabel.visible

	if Input.is_action_just_pressed("debug_quit"):
		print("Stopping Execution")
		get_tree().quit()

	if Input.is_action_just_pressed("debug_reload_scene"):
		print("Reloading scene")
		print(get_tree().reload_current_scene())

	if Input.is_action_just_pressed("debug_toggle_fullscreen"):
		print("Toggling window mode")
		OS.window_fullscreen = !OS.window_fullscreen

	if (Input.is_action_just_pressed("debug_toggle_collisions") == true):
		var stree = get_tree()
		stree.debug_collisions_hint = !stree.debug_collisions_hint
		print("Toggling Visible Collisions")

	#take screenshot
	if Input.is_action_just_pressed("debug_take_screenshot"):
		print("Taking Screenshot")
		#if Input.is_key_pressed(KEY_F12) == true and screenshotkeydown == false:
		yield(get_tree(), "idle_frame")
		yield(get_tree(), "idle_frame")
		var capture = get_viewport().get_texture().get_data()
		capture.flip_y()

		var timestamp = 0
		print("Taking Screenshot")
		#steam style file name
		timestamp = (OS.get_datetime().year * 10000000000)
		timestamp += (OS.get_datetime().month * 1000000000)
		timestamp += (OS.get_datetime().day * 1000000)
		timestamp += (OS.get_datetime().hour * 10000)
		timestamp += (OS.get_datetime().minute * 100)
		timestamp += (OS.get_datetime().second)
		print("user://"+var2str(timestamp)+".png")
		capture.save_png("user://"+var2str(timestamp)+".png")