如何在动画期间更改 Sprite 的图像? [英] How to change an image of a Sprite during the animation?
本文介绍了如何在动画期间更改 Sprite 的图像?的处理方法,对大家解决问题具有一定的参考价值,需要的朋友们下面随着小编来一起学习吧!
问题描述
我想在每次停止时更改对象 worker
的图像.
I want to change an image of the object worker
each time when it stops.
class Worker(pygame.sprite.Sprite):
def __init__(self, image_file, location, *groups):
# we set a _layer attribute before adding this sprite to the sprite groups
# we want the workers on top
self._layer = 1
pygame.sprite.Sprite.__init__(self, groups)
self.image = pygame.transform.scale(pygame.image.load(image_file).convert_alpha(), (40, 40))
self.rect = self.image.get_rect(topleft=location)
# let's call this handy function to set a random direction for the worker
self.change_direction()
# speed is also random
self.speed = random.randint(1, 3)
def change_direction(self):
# let's create a random vector as direction, so we can move in every direction
self.direction = pygame.math.Vector2(random.randint(-1,1), random.randint(-1,1))
# we don't want a vector of length 0, because we want to actually move
# it's not enough to account for rounding errors, but let's ignore that for now
while self.direction.length() == 0:
self.direction = pygame.math.Vector2(random.randint(-1,1), random.randint(-1,1))
# always normalize the vector, so we always move at a constant speed at all directions
self.direction = self.direction.normalize()
def update(self, screen):
# there is a less than 1% chance every time that direction is changed
if random.uniform(0,1)<0.005:
self.change_direction()
# now let's multiply our direction with our speed and move the rect
vec = [int(v) for v in self.direction * self.speed]
self.rect.move_ip(*vec)
# if we're going outside the screen, move back and change direction
if not screen.get_rect().contains(self.rect):
self.change_direction()
self.rect.clamp_ip(screen.get_rect())
我尝试创建预加载图像的缓存
I try to create a cache of pre-loaded images
image_cache = {}
def get_image(key):
if not key in image_cache:
image_cache[key] = pygame.image.load(key)
return image_cache[key]
那我假设有必要在def __init__
中加入如下代码:
Then I assume that it is necessary to add the following code into def __init__
:
images = ["worker.png", "worker_stopped.png"]
for i in range(0,len(images)):
self.images[i] = get_image(images[i])
并将以下代码写入def update(self)
:
if self.direction.length() == 0:
self.image = self.images[1]
else:
self.image = self.images[0]
但是,它似乎无法正常工作.旧图像 worker.png
没有消失,整个动画被锁定.
However, it does not seem to work properly. The old image worker.png
does not disappear and the whole animation gets locked.
推荐答案
我认为您应该引入某种状态来指示工作线程是否正在运行.这是一个例子.注意评论:
I think you should introduce some kind of state to indicate that the worker is running or not. Here's an example. Note the comments:
class Worker(pygame.sprite.Sprite):
# we introduce to possible states: RUNNING and IDLE
RUNNING = 0
IDLE = 1
def __init__(self, location, *groups):
# each state has it's own image
self.images = {
Worker.RUNNING: pygame.transform.scale(get_image("worker.png"), (40, 40)),
Worker.IDLE: pygame.transform.scale(get_image("worker_stopped.png"), (40, 40))
}
self._layer = 1
pygame.sprite.Sprite.__init__(self, groups)
# let's keep track of the state and how long we are in this state already
self.state = Worker.IDLE
self.ticks_in_state = 0
self.image = self.images[self.state]
self.rect = self.image.get_rect(topleft=location)
self.direction = pygame.math.Vector2(0, 0)
self.speed = random.randint(2, 4)
self.set_random_direction()
def set_random_direction(self):
# random new direction or standing still
vec = pygame.math.Vector2(random.randint(-100,100), random.randint(-100,100)) if random.randint(0, 5) > 1 else pygame.math.Vector2(0, 0)
# check the new vector and decide if we are running or fooling around
length = vec.length()
speed = sum(abs(int(v)) for v in vec.normalize() * self.speed) if length > 0 else 0
if length == 0 or speed == 0:
new_state = Worker.IDLE
self.direction = pygame.math.Vector2(0, 0)
else:
new_state = Worker.RUNNING
self.direction = vec.normalize()
self.ticks_in_state = 0
self.state = new_state
# use the right image for the current state
self.image = self.images[self.state]
def update(self, screen):
self.ticks_in_state += 1
# the longer we are in a certain state, the more likely is we change direction
if random.randint(0, self.ticks_in_state) > 30:
self.set_random_direction()
# now let's multiply our direction with our speed and move the rect
vec = [int(v) for v in self.direction * self.speed]
self.rect.move_ip(*vec)
# if we're going outside the screen, change direction
if not screen.get_rect().contains(self.rect):
self.direction = self.direction * -1
self.rect.clamp_ip(screen.get_rect())
这篇关于如何在动画期间更改 Sprite 的图像?的文章就介绍到这了,希望我们推荐的答案对大家有所帮助,也希望大家多多支持IT屋!
查看全文