How to

####Scripting How-to

• How to clone a node

var orig = get_node("SomeNode")
var copy = orig.duplicate()
add_child(copy) # copied node has to be add to scene tree manually

• How to use JSON in GDScript

var d={}
var err = d.parse_json(json_string)
if (err!=OK):
    print("error parsing json")

• How to use multi-dimension array

var a =[[1,2],[3,4]]

• How to save data to file system

var gold = 150 # I have lots of gold!
var f = File.new()
var err=f.open("user://some_data_file",File.WRITE) #TODO: handle errors and such!
# Note: You could probably just use store_var() for many purposes
f.store_8(5) # store an integer
f.store_string("some gold") # store a string
f.store_var(gold) # store a variable
f.store_line("gold="+str(gold)) # store a line
f.close() # we're done writing data, close the file

• How to load data from file system

var my_num
var my_string
var my_gold
var save_file = "user://some_data_file"
var f = File.new()
if f.file_exists(save_file): # check if the file exists
	f.open(save_file, File.READ) # try opening it with read access
	if f.is_open(): # we opened it, let's read some data!
		my_num = f.get_8() # retrieve the number
		my_string = f.get_string() # retrieve the string
		my_gold = f.get_var() # retrieve the gold variable
		my_line = f.get_line()
		f.close() # data's all here, close the file
		print("Data loaded.") # debug message
	else: # failed to open the file - maybe a permission issue?
		print("Unable to read file!")
else: # file doesn't exist, probably set vars to some defaults, etc.
	print("File does not exist.")

• How to set a function's parameter default

func my_function(my_param="default value"):

• How to display fps

extends Label # attach me to a label

func _ready():
	set_process(true)

func _process(d):
	set_text(str(OS.get_frames_per_second()))

• How to draw a polygon and its points with an outline

func _drawPolygon(pointArray):
	var i = 1;
	var colors = [
	Color(0.5,0.5,0.5),
	Color(0.5,0.5,0.5), 
	Color(0.5,0.5,0.5), 
	Color(0.5,0.5,0.5)
	];
	var uvs = [];
	var prevpoint = null;
	
	#Fill the polygon shape
	draw_polygon(pointArray, colors, uvs);
	
	#Then draw a circle at each point, and then lines between them
	for p in pointArray: #for each point as "p" in the array points
	
		draw_circle(p, 10, Color(1,1,1)); 
		#Draw a circle at the point, with a radius of 
		#10 and the color white
		
		#Check if this point was the first point, if it isn't, 
		#then draw a line from the previous point to this point
		if prevpoint != null:
			draw_line(prevpoint, p, Color(1,1,1),5)
			prevpoint = p;
			#^^set the prevpoint for the next loop
		else:
			prevpoint = p;
			
		#check if the loop has reached the last point,
		#then draw a line from the last point to the first point (points[0]
		if i == points.size():
			draw_line(p, pointArray[0], Color(1,1,1),5)
			print("array end");
			#Just to make sure we got all the way trough :)
		i+=1;
		#now increase the interval in order to keep checking if 
		#we're at then end of the array

• How to set a global variable

Globals.set("my_global", 6)

• How to get a global variable

print ( Globals.get("my_global") )

• How to quit the game

get_scene().quit()

• How to change label font color

label.add_color_override("font_color", <desired_color>)

• How to hide the mouse cursor

Input.set_mouse_mode(Input.MOUSE_MODE_HIDDEN)

• How to show the mouse cursor

Input.set_mouse_mode(Input.MOUSE_MODE_VISIBLE)

• How to use a PNG image as mouse cursor

func _ready():
	Input.set_mouse_mode(Input.MOUSE_MODE_HIDDEN)
	var cursor = load("res://cursor.png")
	VisualServer.cursor_set_texture(cursor,Vector2(0,0),0)
	VisualServer.cursor_set_visible(true, 0)
	set_process_input(true)

func _input(ev):
	if (ev.type == InputEvent.MOUSE_MOTION):
		VisualServer.cursor_set_pos(ev.pos,0)

• How to get mouse click position
  You can get mouse click position in _process or _input:

use _process:

func _ready():
	set_process(true)	

func _process(delta):
	if (Input.is_mouse_button_pressed(1)):
		print("Left click: ", Input.get_mouse_pos())
	if (Input.is_mouse_button_pressed(2)):
		print("Right click: ", Input.get_mouse_pos())
	if (Input.is_mouse_button_pressed(3)):
		print("Middle click: ", Input.get_mouse_pos())	

use _input:

func _ready():	
	set_process_input(true)

func _input(ev):
	if (ev.type == InputEvent.MOUSE_BUTTON):
		print("Mouse event:", ev.pos)

• How to check if a directory exist

# Checking if a directory exist in resource data directory
var res_dir = Directory.new()
if ( res_dir.dir_exists("res://my_dir") ):
	print("res://my_dir exist!")

# Checking if a directory exist in user data directory
var user_dir = Directory.new()
user_dir.open("user://")
if ( user_dir.dir_exists("user://my_dir") ):
	print("user://my_dir exist!")

# Checking if a directory exist in file system
var fs_dir = Directory.new()
fs_dir.open("")
if ( fs_dir.dir_exists("c:\\Windows") ): # guilty as charged -- marynate
	print("c:\\Windows exist!")

• How to check data type

var a_var = 1

var type = typeof(a_var)

if (type==TYPE_INT):
	print("it's an int")
elif (type==TYPE_REAL):
	print("it's a float")