在pygame的类/子类中设置和显示精灵时遇到问题

您的代码相当混乱，但是请放心，让我们逐步创建一个简单的pygame游戏步骤。尝试了解每个步骤的作用。

首先，让我们从游戏的基本框架开始，如下所示：

import pygame

def main():
    screen = pygame.display.set_mode((640, 480))
    clock = pygame.time.Clock()
    while True:
        events = pygame.event.get()
        for e in events:
            if e.type == pygame.QUIT:
                return
        screen.fill('grey')
        pygame.display.flip()
        clock.tick(60)

if __name__ == '__main__':
    main()

在这里，我们有一个简单的main功能和简单的游戏循环，它只是监听QUIT事件，使一切灰色和限制帧率到60你不具备有一个main功能和__name__检查，但这样做是很好的实践它允许您导入文件而无需运行游戏。另外，我帮助不要污染全局名称空间。

好，让我们创建一些Sprites：

import pygame
from random import randint, choice

class Animal(pygame.sprite.Sprite):
    
    colors = ['lightblue', 'blue', 'darkblue', 'dodgerblue']

    def __init__(self, pos=None, color=None):
        super().__init__()
        self.image = pygame.Surface((32, 32))
        self.image.fill(color if color else choice(Animal.colors))
        self.rect = self.image.get_rect(center = pos if pos else (randint(100, 540), randint(100, 380)))

def main():
    screen = pygame.display.set_mode((640, 480))
    clock = pygame.time.Clock()
    
    animals = pygame.sprite.Group()
    animals.add(Animal())
    animals.add(Animal())
    animals.add(Animal())

    while True:
        events = pygame.event.get()
        for e in events:
            if e.type == pygame.QUIT:
                return
        screen.fill('grey')
        animals.draw(screen)
        pygame.display.flip()
        clock.tick(60)

if __name__ == '__main__':
    main()

要Sprite在pygame中使用该类，该类需要一个image属性（一个Surface）和一个rect属性（一个），Rect并包含的位置和大小Surface。如果创建Sprite这样的对象，则可以利用Group该类（或其子类）来绘制和更新精灵。为了画些东西，我在一个组中添加了三个动物，animals并调用draw函数，将screenSurface作为参数传递，这样就Group知道了在哪里将动物的图像变灰。

到目前为止，由于这很无聊，因此让我们向精灵添加一些行为：

import pygame
from random import randint, choice

class Animal(pygame.sprite.Sprite):
    
    colors = ['lightblue', 'blue', 'darkblue', 'dodgerblue']

    def __init__(self, pos=None, color=None):
        super().__init__()
        self.image = pygame.Surface((32, 32))
        self.image.fill(color if color else choice(Animal.colors))
        self.rect = self.image.get_rect(center = pos if pos else (randint(100, 540), randint(100, 380)))
        self.pos = pygame.Vector2(*self.rect.center)
        self.speed = 3
        self.direction = pygame.Vector2(1, 0).rotate(randint(0, 360))

    def update(self, dt):
        v = self.direction * self.speed
        while not pygame.display.get_surface().get_rect().contains(self.rect.move(v)):
            self.direction = pygame.Vector2(1, 0).rotate(randint(0, 360))
            v = self.direction * self.speed
        self.pos += v
        self.rect.center = self.pos

def main():
    screen = pygame.display.set_mode((640, 480))
    clock, dt = pygame.time.Clock(), 0
    
    animals = pygame.sprite.Group()
    animals.add(Animal())
    animals.add(Animal())
    animals.add(Animal())

    while True:
        events = pygame.event.get()
        for e in events:
            if e.type == pygame.QUIT:
                return
                
        animals.update(dt/1000)
        
        screen.fill('grey')
        animals.draw(screen)
        pygame.display.flip()
        dt = clock.tick(60)

if __name__ == '__main__':
    main()

As you can see, we keep all the moving logic in the Animal class. The only thing that changed in the game loop is that we keep track of the delta time dt to ensure a constant frame rate (honestly, that's not that important in a small example like this, but again, good practice), and pass it to the groups update function, which in turn will call the update function of each sprite it contains.

In the Animal class, we use some simple vector math to move the sprite: we have a speed and a direction (which is a vector); and also an additional pos vector. Changing the position is easy with vectors because we can just do something like pos = pos + direction * speed, and changing the direction is simple too if we just randomly rotate the direction vector.

If you want to create a 2D game with moving parts I recommend that you learn a litte bit of vector math if you didn't already learn it in school. You don't need to know much more than the fact that you can easily add them up or multiply them etc.

Remember that the sprite is drawn at the coordinate of its rect, so we need to update the rect's position, too.

Pygame's Rect class has some handy functions, too. Just look how we check if the sprite would go out of screen. We can simply grab the Rect of the display surface, move the Sprite's Rect and check if it's still inside the screen rect. If not, we randomly rotate our direction vector (well, it's not 100% perfect, but KISS).

So what about other sprites? Let's just subclass our Animal class, change the speed and color and the behaviour by overwriting the update function:

import pygame
import pygame.freetype
from random import randint, choice
from math import hypot

class Animal(pygame.sprite.Sprite):
    
    colors = ['lightblue', 'blue', 'darkblue', 'dodgerblue']

    def __init__(self, pos=None, color=None, *grps):
        super().__init__(*grps)
        self.image = pygame.Surface((32, 32))
        self.color = color if color else choice(Animal.colors)
        self.image.fill(self.color)
        self.rect = self.image.get_rect(center = pos if pos else (randint(100, 540), randint(100, 380)))
        self.pos = pygame.Vector2(*self.rect.center)
        self.speed = 3
        self.direction = pygame.Vector2(1, 0).rotate(randint(0, 360))

    def update(self, dt):
        v = self.direction * self.speed
        while not pygame.display.get_surface().get_rect().contains(self.rect.move(v)):
            self.direction = pygame.Vector2(1, 0).rotate(randint(0, 360))
            v = self.direction * self.speed
        self.pos += v
        self.rect.center = self.pos


class Preditor(Animal):
    
    def __init__(self, animals, pos=None, color=None, *grps):
        super().__init__(pos, color or 'red', *grps)
        self.speed = 4
        self.target = None
        self.animals = animals
        self.eaten = 0
        self.font = pygame.freetype.SysFont(None, 16)
        self.font.render_to(self.image, (10, 10), str(self.eaten), 'white')

    def get_nearest_animal(self):
        target = None
        distance = None
        for animal in self.animals:
            pygame.draw.line(pygame.display.get_surface(), 'darkgrey', self.pos, animal.pos)
            if not target:
                target = animal
                distance = hypot(animal.pos.x - self.pos.x, animal.pos.y - self.pos.y)
            else:
                new_distance = hypot(animal.pos.x - self.pos.x, animal.pos.y - self.pos.y)
                if new_distance < distance:
                    target = animal
                    distance = new_distance
        if target:
            pygame.draw.line(pygame.display.get_surface(), 'green', self.pos, target.pos)
        return target

    def update(self, dt):
        self.target = self.get_nearest_animal()
        if self.target:
            self.direction = (self.target.pos - self.pos).normalize()
        else:
            self.direction = pygame.Vector2(0, 0)
        
        self.pos += self.direction * self.speed
        self.rect.center = self.pos
        
        if self.target and self.rect.colliderect(self.target.rect):
            self.target.kill()
            self.image.fill(self.color)
            self.eaten += 1
            self.font.render_to(self.image, (10, 10), str(self.eaten), 'white')

def main():
    pygame.init()
    screen = pygame.display.set_mode((640, 480))
    clock, dt = pygame.time.Clock(), 0
    
    animals = pygame.sprite.Group()
    all_sprites = pygame.sprite.Group()
    for _ in range(5):
        Animal(None, None, animals, all_sprites)
    Preditor(animals, None, None, all_sprites)

    while True:
        events = pygame.event.get()
        for e in events:
            if e.type == pygame.QUIT:
                return
            if e.type == pygame.KEYDOWN:
                Animal(None, None, animals, all_sprites)
        
        screen.fill('grey')
        all_sprites.update(dt/1000)
        all_sprites.draw(screen)
        pygame.display.flip()
        dt = clock.tick(60)

if __name__ == '__main__':
    main()

Sprites can be part of multiple groups, and we use that here to give the Predator a list of all its victims it can hunt and eat. Again, see how all sprite behaviour is inside the sprite classes. The only thing the main loop does is creating the initial state telling the sprite groups to update and draw all their sprites (and adding new Animals by pressing a key, because why not). Also note how we can use kill to remove it from all it groups, basically removing it from the game.

Hope that helps and gives you an idea on how to organize your pygame game.

只是玩一点。那些需要吃饭才能生存和繁殖的动物怎么样？捕食者只需要触手可及的较慢动物，如果没有，就吃其他捕食者甚至植物？

import pygame
import pygame.freetype
from random import randint, choice
from math import hypot
from dataclasses import dataclass

class Plant(pygame.sprite.Sprite):
    
    colors = ['green', 'lightgreen', 'darkgreen']

    def __init__(self, pos=None, color=None, *grps):
        self._layer = -10
        super().__init__(*grps)
        self.image = pygame.Surface((24, 24))
        self.color = color if color else choice(Plant.colors)
        self.image.fill(self.color)
        self.rect = self.image.get_rect(center = pos if pos else (randint(10, 630), randint(10, 470)))
        self.pos = pygame.Vector2(*self.rect.center)

class Animal(pygame.sprite.Sprite):
    
    font = None
    colors = ['lightblue', 'blue', 'darkblue', 'dodgerblue']

    def __init__(self, system, pos=None, color=None, *grps):
        super().__init__(*grps)
        self.image = pygame.Surface((24, 24))
        self.color = color if color else choice(Animal.colors)
        self.image.fill(self.color)
        self.rect = self.image.get_rect(center = pos if pos else (randint(100, 540), randint(100, 380)))
        self.pos = pygame.Vector2(*self.rect.center)
        self.speed = randint(20, 50) / 10
        self.direction = pygame.Vector2(1, 0).rotate(randint(0, 360))
        self.reproduce = randint(1, 5)
        self.sleep = 0
        self.eaten = 0
        self.energy = 10
        self.system = system
        if not self.font:
            Animal.font = pygame.freetype.SysFont(None, 16)

    def base_update(self, dt):
        self.energy -= dt * (self.speed / 2)
        if self.energy <= 0:
            self.kill()
            return False
    
        if self.sleep >= 0:
            self.sleep -= dt
            return False

        self.reproduce -= dt
        if self.reproduce <= 0 and self.energy >= 4:
            self.reproduce = randint(1, 7)
            self.__class__(self.system, self.pos, None, *self.groups())
            self.sleep = 0.5
            self.energy -= 1.5

        return True

    def update_image(self):
        self.image.fill(self.color)
        self.image.set_alpha(122 if self.sleep > 0 else 255)
            
        pygame.draw.rect(self.image, 'green', (0, 0, self.rect.width * self.energy/10, 3))
        self.font.render_to(self.image, (7, 7), str(self.eaten), 'white')

    def get_nearest_target(self, targets, max_distance=250):
        target = None
        distance = None
        for possible_target in targets:
            if possible_target == self or hasattr(possible_target, 'speed') and possible_target.speed > self.speed:
                continue
            
            new_distance = hypot(possible_target.pos.x - self.pos.x, possible_target.pos.y - self.pos.y)
            pygame.draw.line(pygame.display.get_surface(), 'darkgrey' if new_distance > max_distance else 'white', self.pos, possible_target.pos)
            if new_distance <= max_distance:
                if not target or new_distance < distance:
                    target = possible_target
                    distance = new_distance
        if target:
            pygame.draw.line(pygame.display.get_surface(), 'green', self.pos, target.pos)
        return target

    def update(self, dt):
        if not self.base_update(dt) or len(self.groups()) == 0:
            return
            
        v = self.direction * self.speed
        while not pygame.display.get_surface().get_rect().contains(self.rect.move(v)):
            self.direction = pygame.Vector2(1, 0).rotate(randint(0, 360))
            v = self.direction * self.speed

        for plant in self.system.plants:
            if plant.rect.colliderect(self.rect) and self.energy < 8:
                plant.kill()
                self.eaten += 1
                self.energy = 10
                continue

        self.pos += v
        self.rect.center = self.pos
        self.update_image()

class Preditor(Animal):
    
    def __init__(self, system, pos=None, color=None, *grps):
        super().__init__(system, pos, color or 'red', *grps)
        self.speed = randint(20, 40) / 10
        self.target = None
        self.update_image()

    def update(self, dt):
        if not self.base_update(dt) or len(self.groups()) == 0:
            return

        self.target = self.get_nearest_target(self.system.animals)
        if not self.target:
            self.target = self.get_nearest_target(self.system.preditors)
        if not self.target:
            self.target = self.get_nearest_target(self.system.plants)
            
        if self.target:
            self.direction = (self.target.pos - self.pos).normalize()
        else:
            self.direction = pygame.Vector2(0, 0)
        
        self.pos += self.direction * self.speed
        self.rect.center = self.pos
        
        if self.target and self.rect.colliderect(self.target.rect):
            self.target.kill()
            self.eaten += 1
            self.sleep = 0.5
            self.energy += 3
            if self.energy > 10:
                self.energy = 10

        self.update_image()

@dataclass
class System:
    plants: object
    animals: object
    preditors: object

def main():
    pygame.init()
    screen = pygame.display.set_mode((640, 480))
    clock, dt = pygame.time.Clock(), 0

    GROW = pygame.USEREVENT + 1
    pygame.time.set_timer(GROW, 1000)

    
    animals = pygame.sprite.Group()
    plants = pygame.sprite.Group()
    preditors = pygame.sprite.Group()
    all_sprites = pygame.sprite.LayeredUpdates()

    system = System(plants, animals, preditors)
    
    for _ in range(4):
        Animal(system, None, None, animals, all_sprites)

    for _ in range(5):
        Plant(None, None, plants, all_sprites)

    Preditor(system, None, None, preditors, all_sprites)

    while True:
        events = pygame.event.get()
        for e in events:
            if e.type == pygame.QUIT:
                return
            if e.type == pygame.KEYDOWN:
                Animal(system, None, None, animals, all_sprites)
            if e.type == GROW:
                for _ in range(5):
                    Plant(None, None, plants, all_sprites)
        
        screen.fill('grey')
        all_sprites.update(dt/1000)
        all_sprites.draw(screen)
        pygame.display.flip()
        dt = clock.tick(30)

if __name__ == '__main__':
    main()