python - 群体碰撞在 Pygame 的平台滚动条上不起作用

Question

我关注这个tutorial我已将 class Opponent() 添加到 class Platform()，如图 here 。接下来我一直在尝试将groupcollide_and_loop_for添加到完整的代码中，以便对手被子弹击中时被移除。我一直在看这个question关于在 class Opponent() 本身中使用 groupcollide。我尝试了几种方法在 while not done 中的 def main 中调用 groupcollide 但我没有得到任何结果或任何错误，它只是没有不起作用。

groupcollide_and_loop_for:

    collided_opponents = pygame.sprite.groupcollide(opponents, bullet_list, False, True)
    for opponent, bullets in collided_opponents.items():
        for bullet in bullets:
            score += 1  # Increment the score.
            opponent.lives -= 1  # Decrement the lives.
            pygame.display.set_caption(str(score))

将上面的 groupcollide 和 for 循环部署到下面的代码中:

import pygame

# Global constants
bulletpicture = pygame.image.load("bullet.png") 
# Colors
BLACK = (0, 0, 0)
WHITE = (255, 255, 255)
GREEN = (0, 255, 0)
RED = (255, 0, 0)
BLUE = (0, 0, 255)

# Screen dimensions
SCREEN_WIDTH = 800
SCREEN_HEIGHT = 600


class Player(pygame.sprite.Sprite):
    """
    This class represents the bar at the bottom that the player controls.
    """

    # -- Methods
    def __init__(self):
        """ Constructor function """

        # Call the parent's constructor
        super().__init__()

        # Create an image of the block, and fill it with a color.
        # This could also be an image loaded from the disk.
        width = 40
        height = 60
        self.image = pygame.Surface([width, height])
        self.image.fill(RED)

        # Set a referance to the image rect.
        self.rect = self.image.get_rect()

        # Set speed vector of player
        self.change_x = 0
        self.change_y = 0

        # List of sprites we can bump against
        self.level = None

    def update(self):
        """ Move the player. """
        # Gravity
        self.calc_grav()

        # Move left/right
        self.rect.x += self.change_x

        # See if we hit anything
        block_hit_list = pygame.sprite.spritecollide(self, self.level.platform_list, False)
        for block in block_hit_list:
            # If we are moving right,
            # set our right side to the left side of the item we hit
            if self.change_x > 0:
                self.rect.right = block.rect.left
            elif self.change_x < 0:
                # Otherwise if we are moving left, do the opposite.
                self.rect.left = block.rect.right

        # Move up/down
        self.rect.y += self.change_y

        # Check and see if we hit anything
        block_hit_list = pygame.sprite.spritecollide(self, self.level.platform_list, False)
        for block in block_hit_list:

            # Reset our position based on the top/bottom of the object.
            if self.change_y > 0:
                self.rect.bottom = block.rect.top
            elif self.change_y < 0:
                self.rect.top = block.rect.bottom

            # Stop our vertical movement
            self.change_y = 0

    def calc_grav(self):
        """ Calculate effect of gravity. """
        if self.change_y == 0:
            self.change_y = 1
        else:
            self.change_y += .35

        # See if we are on the ground.
        if self.rect.y >= SCREEN_HEIGHT - self.rect.height and self.change_y >= 0:
            self.change_y = 0
            self.rect.y = SCREEN_HEIGHT - self.rect.height

    def jump(self):
        """ Called when user hits 'jump' button. """

        # move down a bit and see if there is a platform below us.
        # Move down 2 pixels because it doesn't work well if we only move down 1
        # when working with a platform moving down.
        self.rect.y += 2
        platform_hit_list = pygame.sprite.spritecollide(self, self.level.platform_list, False)
        self.rect.y -= 2

        # If it is ok to jump, set our speed upwards
        if len(platform_hit_list) > 0 or self.rect.bottom >= SCREEN_HEIGHT:
            self.change_y = -10

    # Player-controlled movement:
    def go_left(self):
        """ Called when the user hits the left arrow. """
        self.change_x = -6

    def go_right(self):
        """ Called when the user hits the right arrow. """
        self.change_x = 6

    def stop(self):
        """ Called when the user lets off the keyboard. """
        self.change_x = 0


class Platform(pygame.sprite.Sprite):
    """ Platform the user can jump on """

    def __init__(self, width, height):
        """ Platform constructor. Assumes constructed with user passing in
            an array of 5 numbers like what's defined at the top of this code.
            """
        super().__init__()

        self.image = pygame.Surface([width, height])
        self.image.fill(GREEN)

        self.rect = self.image.get_rect()


class Level():
    """ This is a generic super-class used to define a level.
        Create a child class for each level with level-specific
        info. """

    def __init__(self, player):
        """ Constructor. Pass in a handle to player. Needed for when moving
            platforms collide with the player. """
        self.platform_list = pygame.sprite.Group()
        self.enemy_list = pygame.sprite.Group()
        self.player = player

        # How far this world has been scrolled left/right
        self.world_shift = 0

    # Update everythign on this level
    def update(self):
        """ Update everything in this level."""
        self.platform_list.update()
        self.enemy_list.update()

    def draw(self, screen):
        """ Draw everything on this level. """

        # Draw the background
        screen.fill(BLUE)

        # Draw all the sprite lists that we have
        self.platform_list.draw(screen)
        self.enemy_list.draw(screen)

    def shift_world(self, shift_x):
        """ When the user moves left/right and we need to scroll
        everything: """

        # Keep track of the shift amount
        self.world_shift += shift_x

        # Go through all the sprite lists and shift
        for platform in self.platform_list:
            platform.rect.x += shift_x

        for enemy in self.enemy_list:
            enemy.rect.x += shift_x

class Bullet(pygame.sprite.Sprite):
    """This class represents the bullet."""

    def __init__(self,x,y):
        super().__init__()
        self.image = bulletpicture

        self.image.set_colorkey(BLACK) 
        self.rect = self.image.get_rect()
        self.rect.x = x
        self.rect.y = y
    def update(self):
        """Move the bullet."""
        self.rect.y -= 5
        # Remove the bullet if it flies up off the screen
        if self.rect.y < -12:
            self.kill()  # Remove the sprite from all sprite groups.



class Opponent(pygame.sprite.Sprite):

    def __init__(self):

        super().__init__()
        self.image = pygame.image.load("cowboy.png") #.convert()
        self.rect = self.image.get_rect()
        self.lives = 1
        self.rect.x = 50
        self.rect.y = 280
        self.change_x = 1
        self.change_y = 0
        # List of sprites we can bump against
        self.level = None

        pass
    def update(self):
        if self.lives <= 0:
            self.kill()  # Remove the sprite from all sprite groups.
        self.rect.x += self.change_x
        if self.rect.x > 280:
           self.change_x *= -1
           self.rect.x += self.change_x
        if self.rect.x < 0:
           self.change_x *= -1
           self.rect.x += self.change_x
        pass


# Create platforms for the level
class Level_01(Level):
    """ Definition for level 1. """

    def __init__(self, player):
        """ Create level 1. """

        # Call the parent constructor
        Level.__init__(self, player)

        self.level_limit = -1000

        # Array with width, height, x, and y of platform
        level = [[210, 70, 500, 500],
                 [210, 70, 800, 400],
                 [210, 70, 1000, 500],
                 [210, 70, 1120, 280],
                 ]

        # Go through the array above and add platforms
        for platform in level:
            block = Platform(platform[0], platform[1])
            block.rect.x = platform[2]
            block.rect.y = platform[3]
            block.player = self.player
            self.platform_list.add(block)

        for enemy in level:
            opponent = Opponent()
            opponent.rect.x = 150
            opponent.rect.y = 280
            opponent.player = self.player
            self.enemy_list.add(opponent)

# Create platforms for the level
class Level_02(Level):
    """ Definition for level 2. """

    def __init__(self, player):
        """ Create level 1. """

        # Call the parent constructor
        Level.__init__(self, player)

        self.level_limit = -1000

        # Array with type of platform, and x, y location of the platform.
        level = [[210, 30, 450, 570],
                 [210, 30, 850, 420],
                 [210, 30, 1000, 520],
                 [210, 30, 1120, 280],
                 ]

        # Go through the array above and add platforms
        for platform in level:
            block = Platform(platform[0], platform[1])
            block.rect.x = platform[2]
            block.rect.y = platform[3]
            block.player = self.player
            self.platform_list.add(block)


def main():
    """ Main Program """
    pygame.init()

    # Set the height and width of the screen
    size = [SCREEN_WIDTH, SCREEN_HEIGHT]
    screen = pygame.display.set_mode(size)

    pygame.display.set_caption("Side-scrolling Platformer")

    # Create the player
    player = Player()

    # Create all the levels
    level_list = []
    level_list.append(Level_01(player))
    level_list.append(Level_02(player))

    # Set the current level
    current_level_no = 0
    current_level = level_list[current_level_no]

    active_sprite_list = pygame.sprite.Group()
    player.level = current_level

    player.rect.x = 340
    player.rect.y = SCREEN_HEIGHT - player.rect.height
    active_sprite_list.add(player)

    # --- NEW
    bullet_list = pygame.sprite.Group()
    player_list = pygame.sprite.Group()
    player_list.add(player)
    opponent = Opponent()
    opponents = pygame.sprite.Group()
    opponents.add(opponent)
    score = 0


    # Loop until the user clicks the close button.
    done = False

    # Used to manage how fast the screen updates
    clock = pygame.time.Clock()

    # -------- Main Program Loop -----------
    while not done:
        for event in pygame.event.get():
            if event.type == pygame.QUIT:
                done = True
            elif event.type == pygame.MOUSEBUTTONDOWN:
                 # Click a mouse button to instantiate a bullet.
                 bullet = Bullet(player.rect.x,player.rect.y)
                 bullet_list.add(bullet)
                 active_sprite_list.add(bullet)

            if event.type == pygame.KEYDOWN:
                if event.key == pygame.K_LEFT:
                    player.go_left()
                if event.key == pygame.K_RIGHT:
                    player.go_right()
                if event.key == pygame.K_UP:
                    player.jump()

            if event.type == pygame.KEYUP:
                if event.key == pygame.K_LEFT and player.change_x < 0:
                    player.stop()
                if event.key == pygame.K_RIGHT and player.change_x > 0:
                    player.stop()

        # Update the player.
        active_sprite_list.update()
 #  ----- The code commented below is what I tried in many ways
        #collided_opponents = pygame.sprite.groupcollide(opponents, bullet_list, False, True)
        #for opponent, bullets in collided_opponents.items():
        #    for bullet in bullets:
        #        score += 1  # Increment the score.
        #        opponent.lives -= 1  # Decrement the lives.
        #        pygame.display.set_caption(str(score))

        # Update items in the level
        current_level.update()

        # If the player gets near the right side, shift the world left (-x)
        if player.rect.right >= 500:
            diff = player.rect.right - 500
            player.rect.right = 500
            current_level.shift_world(-diff)

        # If the player gets near the left side, shift the world right (+x)
        if player.rect.left <= 120:
            diff = 120 - player.rect.left
            player.rect.left = 120
            current_level.shift_world(diff)

        # If the player gets to the end of the level, go to the next level
        current_position = player.rect.x + current_level.world_shift
        if current_position < current_level.level_limit:
            player.rect.x = 120
            if current_level_no < len(level_list)-1:
                current_level_no += 1
                current_level = level_list[current_level_no]
                player.level = current_level

        # ALL CODE TO DRAW SHOULD GO BELOW THIS COMMENT
        current_level.draw(screen)
        active_sprite_list.draw(screen)

        # ALL CODE TO DRAW SHOULD GO ABOVE THIS COMMENT

        # Limit to 60 frames per second
        clock.tick(60)

        # Go ahead and update the screen with what we've drawn.
        pygame.display.flip()

    # Be IDLE friendly. If you forget this line, the program will 'hang'
    # on exit.
    pygame.quit()

if __name__ == "__main__":
    main()

Answer 1

我使用print()来查看对手和子弹的位置。我发现对手永远不会改变位置。

深入研究代码后，我发现您创建了两个对手。

• 在main()中，您创建了opponent，它没有添加到active_sprite_list中，因此它不会移动，也不会显示，但你用它来检查碰撞
• 在Level_01()中，您创建对手，并将其添加到active_sprite_list中，以便它移动并显示在屏幕上，但您不这样做用它来检查碰撞。

因为您检查与永远不会移动的对手的碰撞，因此它永远不会与子弹碰撞。

在main()中你必须删除

opponent = Opponent()
opponents = pygame.sprite.Group()
opponents.add(opponent)

并使用

#opponents = level_list[current_level_no].enemy_list
opponents = current_level.enemy_list

当你改变级别时也可以使用它

current_level_no += 1
current_level = level_list[current_level_no]

#opponents = level_list[current_level_no].enemy_list
opponents = current_level.enemy_list