import pygame

def start_loop():
	global g_timer, g_elapsed
	g_elapsed = 0
	g_elapsed_sec = 0.0
	g_timer = pygame.time.get_ticks()
	
def next_frame(skipping=False):
	global g_timer, g_elapsed, g_elapsed_sec

	newticks = pygame.time.get_ticks()
	#if skipping:
	#	# reset g_timer to it's value from the previous frame
	#	g_timer -= g_elapsed
	g_elapsed = newticks - g_timer
	g_timer = newticks
	g_elapsed_sec = float(g_elapsed) / 1000.0
	
def elapsed():
	"""
	get the amount of time in milliseconds passed since the last frame was displayed
	"""
	return g_elapsed
	
def elapsed_sec():
	"""
	get the amount of time in seconds passed since the last frame was displayed
	"""
	return g_elapsed_sec

def num_frames(delay, offset=0):
	"""
	if you want something to occur every "delay" milliseconds,
	this will return the number of times you should make it happen
	"""
	global g_elapsed, g_timer
	return int((g_timer - offset) / delay) - int((g_timer - g_elapsed - offset) / delay)

def get_timer():
	return g_timer