# Check and sleep to maintain a frame-rate bellow `maximum_fps`
	#
	# Also periodically update `current_fps`
	# Is automatically called at the end of `full_frame`.
	fun limit_fps
	do
		var t = clock.total
		if t >= frame_count_deadline then
			var cfps = frame_count.to_f / 5.0
			self.current_fps = cfps
			frame_count = 0
			frame_count_deadline = t + 5.0
		end
		frame_count += 1

		var mfps = maximum_fps
		if mfps <= 0.0 then return
		var lapse = clock.lapse
		var dt = lapse.to_f
		var target_dt = 1.0 / mfps
		if dt < target_dt then
			var sleep_t = target_dt - dt
			sleep_t.sleep
			clock.lapse
		end
	end