我有一个球对象,它在移动之前在屏幕中间等待一秒钟。这是update
方法:
def update(self, dt):
now = pygame.time.get_ticks() / 1000
if now - self._spawn_time >= BALL_WAIT_TIME:
self.rect = self.calcnewpos(dt)
self.handle_collision()
else:
step = 255 / FPS
value = int(self._frame * step)
rgb = (value, value, value)
self._draw_ball(rgb)
self._frame += 1
那一秒发生在else子句之下。我的目标是在那段时间内让球的图像从黑色 (8, 8, 8)
变为白色 (255, 255, 255)
,但实际上它_draw_ball
什么也没做。
def _draw_ball(self, rgb):
pygame.draw.circle(self.image, rgb, self.rect.center, BALL_RADIUS)
有趣的是,它在第一次被调用时就起作用了__init__
。我尝试从更新中取出行并在另一个模块中自行测试此代码,但无法弄清楚问题所在。为什么pygame.draw.circle
不使用更新方法传递的颜色绘制圆圈?
这是整个班级:
#!python3
class Ball(pygame.sprite.Sprite):
def __init__(self, game, velocity):
super(Ball, self).__init__()
self.image = pygame.Surface((BALL_RADIUS*2, BALL_RADIUS*2))
self.image.fill(BLACK)
self.image.set_colorkey(BLACK, RLEACCEL)
self.rect = self.image.get_rect()
screen = pygame.display.get_surface()
self.area = screen.get_rect().inflate(-GAP*2, 0)
self.velocity = velocity
self.game = game
self.start_to_the = random.choice(['left', 'right'])
self._draw_ball(BALL_COLOR)
self.reinit()
def _draw_ball(self, rgb):
pygame.draw.circle(self.image, rgb, self.rect.center, BALL_RADIUS)
def _hit_topbottom(self):
return self.rect.top < self.area.top or self.rect.bottom > self.area.bottom
def _hit_leftright(self):
if self.rect.left < self.area.left: return 'left'
elif self.rect.right > self.area.right: return 'right'
else: return 0
def reinit(self):
self._spawn_time = pygame.time.get_ticks() / 1000
self._frame = 1
if self.start_to_the == 'left':
self.velocity = Vec2D(-BALL_SPEED, 0)
else:
self.velocity = Vec2D(BALL_SPEED, 0)
self.rect.center = self.area.center
def update(self, dt):
now = pygame.time.get_ticks() / 1000
if now - self._spawn_time >= BALL_WAIT_TIME:
self.rect = self.calcnewpos(dt)
self.handle_collision()
else:
step = 255 / FPS
value = int(self._frame * step)
rgb = (value, value, value)
self.image.fill(rgb)
self._frame += 1
def calcnewpos(self, dt):
(dx, dy) = self.velocity.x, self.velocity.y
return self.rect.move(dx, dy)
def handle_collision(self):
(dx, dy) = self.velocity.x, self.velocity.y
if self._hit_topbottom():
dy = -dy
elif self._hit_leftright():
side = self._hit_leftright()
self.game.enemy.update_hitpos()
self.game.increase_score(side)
if side == 'left': self.start_to_the = 'right'
elif side == 'right': self.start_to_the = 'left'
self.reinit()
return
else:
if self.hit_paddle():
paddle = self.hit_paddle()
paddle.handle_collision()
if paddle == self.game.paddles['left']:
self.rect.left = GAP + PADDLE_WIDTH
elif paddle == self.game.paddles['right']:
self.rect.right = SCREEN_WIDTH - (GAP + PADDLE_WIDTH)
dx = -dx
dy = (self.rect.centery - paddle.rect.centery)
dy = (math.copysign(min(abs(dy) // 16 * 16, 32), dy)) / 4
paddle.handle_collision()
self.velocity = Vec2D(dx, dy)
def hit_paddle(self):
paddles = self.game.paddles.values()
for paddle in paddles:
if self.rect.colliderect(paddle.rect): return paddle