Capture viewport to image in Godot

ViewPortImage.gd

extends Node2D

func _ready():
	yield(VisualServer, "frame_post_draw")
	
	var img = $ViewportContainer/Viewport.get_texture().get_data()
	img.flip_y()
	img.save_png("vp_image.png")
	
	img = $VP3D/Viewport.get_texture().get_data()
	img.convert(Image.FORMAT_RGBA8) # Retain the transparency
	img.flip_y()
	img.save_png("vp_image.png")
	
	update() # This causes the _draw() function to run

func _draw():
	# Put statements here to draw to the canvas
	pass