Space invaders

#coding:utf-8
import pygame

class Vaisseau():
    '''
    Vaisseaux: Joueur principale
    Poligône bleu 3vies
    '''
    def __init__(self,color, x, y, x1, y1, x2, y2):
        self.color = color
        self.x = x
        self.y = y
        self.x1 = x1
        self.y1 = y1
        self.x2 = x2
        self.y2 = y2
    def draw(self, window):
        #(0, 0, 255)
        pygame.draw.polygon(window,self.color , [(self.x, self.y), (self.x1, self.y1), (self.x2, self.y2)])
        pygame.display.flip()

        '''
        Vies du héros
        '''
        def life(vies):
            vies=3

class Enemi():
    '''
    Ennemis: Bloc qui endommagent le vaisseau
    Ronds rouges -1vie
    '''
    def __init__(self, x1, y1):
        self.x1 = x1
        self.y1 = y1


class Missiles():
    '''
    Class qui crée le missile lancé par le vaisseau
    le missile est vert et rectangulaire
    '''
    def __init__(self, color, Xmissile, Ymissile):
        self.color = color
        self.Xm = Xmissile
        self.Ym = Ymissile
    def draw(self, window):

        pygame.draw.rect(window,self.color , (self.Xm,self.Ym , 5, 10))
        pygame.display.update()


def main():

    pygame.init()

    window = pygame.display.set_mode((750, 750))
    pygame.display.set_caption("Space Invader")

    x = 350
    y = 700
    x1 = 375
    y1 = 670
    x2 = 400
    y2 = 700
    vel = 25
    Ymis = y1
    vel_mis = 20



    game_launched = True

    while game_launched:

        for event in pygame.event.get():
            if event.type == pygame.QUIT:
                game_launched = False


        vaisseau = Vaisseau((0, 0, 255), x, y, x1, y1 , x2, y2)
        vaisseau.draw(window)

        missile = Missiles((0,255,0), x1 , y1)
        missile.draw(window)

        keys = pygame.key.get_pressed()
        if keys[pygame.K_LEFT] and x > 0 and x2 > 0 and x1 > 0 :
            x -= vel
            x1 -= vel
            x2 -= vel
            window.fill((0, 0, 0))

            vaisseau = Vaisseau((0, 0, 255), x, y, x1, y1 , x2, y2)
            vaisseau.draw(window)

            pygame.display.update()

        if keys[pygame.K_RIGHT] and x < 750 and x2 <750 and x1 < 750:
            x += vel
            x1 += vel
            x2 += vel
            window.fill((0, 0, 0))

            vaisseau = Vaisseau((0, 0, 255), x, y, x1, y1 , x2, y2)
            vaisseau.draw(window)

            pygame.display.update()

        if keys[pygame.K_SPACE]:
            while Ymis > 0:

                Ymis -= vel_mis

                window.fill((0,0,0))

                missile = Missiles((0,255,0), x1 , Ymis)
                missile.draw(window)

                continue
                pygame.display.update()


main()