Gestion de la Vélocité en Python avec Pygame

#Python 3.4
from pygame.locals import *
import pygame, time, math

window_size = (1000,  600); pygame.init();
window = pygame.display.set_mode(window_size);
pygame.display.set_caption("V-Force");

Fun = [0, 0, 0];
Bgc = [255, 255, 255];

class Player:
	def __init__(self, x = window_size[0] /2, y = window_size[1] /2, speed = 0.75, speed_max = 75, fx = 0.25, fy = 0.25):
		self.x = x; self.vx = 0; self.fx = fx;
		self.y = y; self.vy = 0; self.fy = fy;
		self.speed = speed;
		self.speed_max = speed_max;

	def move(self, dir):
		if dir == 'up':
			self.vy += -self.speed;

		elif dir == 'down':
			self.vy += self.speed;

		elif dir == 'left':
			self.vx += -self.speed;

		elif dir == 'right':
			self.vx += self.speed;

	def update(self):
		self.x += self.vx;
		self.y += self.vy;

		if self.vx > self.speed_max:
			self.vx = (self.speed_max);

		elif self.vx < (-self.speed_max):
			self.vx = -(self.speed_max);

		if self.vy > self.speed_max:
			self.vy = (self.speed_max);

		elif self.vy < (-self.speed_max):
			self.vy = -(self.speed_max);

		if self.vx > 0:
			self.vx += -self.fx;

			if self.vx < 0:
				self.vx = 0;

		elif self.vx < 0:
			self.vx += self.fx;

			if self.vx > 0:
				self.vx = 0;

		if self.vy > 0:
			self.vy += -self.fy;

			if self.vy < 0:
				self.vy = 0;

		elif self.vy < 0:
			self.vy += self.fy;

			if self.vy > 0:
				self.vy = 0;

	def set(self, x, y):
		self.x = x;
		self.y = y;

	def get(self):
		return {
			'x':self.x, 'y':self.y, 'vx':self.vx, 'vy':self.vy, 'speed':self.speed, 'speed_max':self.speed_max, 'fx':self.fx, 'fy':self.fy,
		};

def Display(window, x, y, s, *text):
	Font = pygame.font.Font(None, s); 
	count = y;

	for line in text:
		window.blit(Font.render(line, True, (255,255,255)), (x, count));
		count += s;

player = Player();
done_prog = False;
while not done_prog:
	pressed = pygame.key.get_pressed(); cube_size = 30;
	pygame.time.Clock().tick(60);

	for event in pygame.event.get():
		if event.type == QUIT:
			done_prog = True;

	if pressed[K_UP]:
		player.move('up');

	if pressed[K_DOWN]:
		player.move('down');

	if pressed[K_LEFT]:
		player.move('left');

	if pressed[K_RIGHT]:
		player.move('right');


	player.update();
	stat = player.get();

	if stat['x'] > window_size[0] + cube_size /2:
		player.set(math.ceil(window_size[0]/6.25) - cube_size, stat['y']);

	if stat['y'] > window_size[1] + cube_size /2:
		player.set(stat['x'], 0 - cube_size);

	if stat['x'] < math.ceil(window_size[0]/6.25) - cube_size:
		player.set(window_size[0], stat['y']);

	if stat['y'] < - cube_size:
		player.set(stat['x'], window_size[1]);
	
	Fun[2] += 1;
	if Fun[2] == 255:
		Fun[2] = 0;
		Fun[1] += 1;

		if Fun[1] == 255:
			Fun[1] = 0;
			Fun[0] += 1;

			if Fun[0] == 255:
				Fun = [0, 0, 0];
	
	Bgc[2] -= 1;
	if Bgc[2] == 0:
		Bgc[2] = 255;
		Bgc[1] -= 1;

		if Bgc[1] == 0:
			Bgc[1] = 255;
			Bgc[0] -= 1;

			if Bgc[0] == 0:
				Bgc = [255, 255, 255];

	pygame.display.flip(); window.fill(Bgc);
	pygame.draw.rect(window, Fun, [stat['x'], stat['y'], cube_size, cube_size]);
	pygame.draw.rect(window, (0, 0, 0), [0, 0, math.ceil(window_size[0] /6.25), window_size[1]]);
	
	Display(window, 10, 10, 20,
		'X:' + str(stat['x']),
		'Y:' + str(stat['y']),
		'___________________',
		'VX:' + str(stat['vx']),
		'VY:' + str(stat['vy']),
		'___________________',
		'FX:' + str(stat['fx']),
		'FY:' + str(stat['fy']),
		'___________________',
		'SPEED:' + str(stat['speed']),
		'SPEED_MAX:' + str(stat['speed_max']),
		'___________________',
		'K_UP:' + str(pressed[K_UP]),
		'K_DOWN:' + str(pressed[K_DOWN]),
		'K_LEFT:' + str(pressed[K_LEFT]),
		'K_RIGHT:' + str(pressed[K_RIGHT]),
		'___________________',
		'CBC:' + str(Fun),
		'BGC:' + str(Bgc),
		'___________________', 
		'Python 3.4.3', 
		'Pygame 1.9.2a0', 
		'', '', '', '',
		'___________________',
		'CREDIT:Creuilcreuil',
	);