Pygame中对象的曲折运动

Question

我希望外星人以之字形移动。

目前他们正在直线下降。

游戏目前处于横盘状态。

这是外星人类

class Alien(Sprite):

    def __init__(self,ss_game):
        super().__init__()

        self.screen = ss_game.screen
        self.settings = ss_game.settings
        self.screen_rect = ss_game.screen.get_rect()

        self.image = pygame.image.load('images/alien_2.bmp')
        self.rect = self.image.get_rect()

        self.rect.x = self.rect.height
        self.rect.y = self.rect.width

        self.x = float(self.rect.x)
        self.y = float(self.rect.y)


    def _check_edges(self):

        screen_rect = self.screen.get_rect()
        if self.rect.top >= screen_rect.top or self.rect.bottom <= self.screen_rect.bottom:
            return True


    def update(self):
        self.rect.x += (self.settings.alien_speed * self.settings.fleet_direction) 

这些是几行代码，它们决定/创建一定数量的外星人并在那里移动。

    def _create_fleet(self):

        alien = Alien(self)
        alien_width, alien_height = alien.rect.size
        ship_width, ship_height = self.ship.rect.size
        space_y = self.settings.screen_height +(alien_height) - ship_height
        number_y = space_y // (2*alien_height) 
        space_x = self.settings.screen_width + (alien_width) - 5 * ship_width
        rows = space_x // (2*alien_height)
        for row in range(rows):
            for number in range(number_y):
                self._create_aliens(number, row)

    def _create_aliens(self,number,row):

        alien = Alien(self)
        alien_width,alien_height = alien.rect.size
        alien.x = alien_width + (1.5*alien_width) * row
        alien.rect.x = alien.x
        alien.rect.y = alien_width + (2*alien_width) * number
        self.aliens.add(alien) 

    def update_aliens(self):

        self.aliens.update()
        self._check_fleet_edges()

    def _check_fleet_edges(self):
        for alien in self.aliens.sprites():
            if alien._check_edges():
                self._change_fleet_direction()
                break

    def _change_fleet_direction(self):
        for alien in self.aliens.sprites():
            alien.rect.x += self.settings.fleet_drop_speed
        self.settings.fleet_direction *= -1

这是当前游戏的图片，外星人右边和外星人左边都有空格

由于更改/实验，代码可能有点混乱， 有什么不明白的可以问我。

目前外星人以直线运动移动，而且速度很快（旁注）。

我希望外星人以曲折的方式移动。

Answer 1

你可以让它们沿着罪恶波移动。在你的情况下，它可能看起来像这样：

class Alien(Sprite):
    def __init__(self,ss_game):
        #...
        self.frequency = 2
        self.ySpeed = 0.01
        self.overallY = self.rect.y
        self.amplitude = 30

 def update(self):
        t = pygame.time.get_ticks() * self.ySpeed % 500
        self.rect.x += (self.settings.alien_speed * self.settings.fleet_direction * self.frequency)
        self.rect.y = (self.amplitude * math.sin(t)) + self.overallY

这是一个独立的例子。

import pygame
import math

ySpeed = 0.01
xVel = 0.1
x = 0
y = 250

amplitude = 20
frequency = 2

window = pygame.display.set_mode((600, 600))
pygame.init()

while True:

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

    #stuff to do with x direction
    x += xVel * frequency
    if (x < 0 or x > 600 - 30):
         xVel *= -1

    #generate the zigzag y
    t = pygame.time.get_ticks() * ySpeed % 500
    zigzagY = (amplitude * math.sin( t )) + y

    #draw
    window.fill((0, 0, 0))
    pygame.draw.rect(window, (255, 255, 255), (x, zigzagY, 30, 30))
    pygame.display.flip()

您的整个更新代码：

import pygame
import math
from pygame.locals import *

class Settings:
    def __init__(self):

        self.screen_width = 1200
        self.screen_height = 800
        self.bg_color = (230, 230, 230)
        self.ship_speed = 1.5

        self.bullet_speed = 1.5
        self.bullet_width = 15
        self.bullet_height = 3
        self.bullet_color = (60, 60, 60)
        self.bullet_allowed = 3

        self.alien_speed = 1
        self.fleet_drop_speed = 10
        self.fleet_direction = 1

class Ship:
    def __init__(self, ai_game):
        self.screen = ai_game.screen

        self.settings = ai_game.settings

        self.screen_rect = ai_game.screen.get_rect()

        self.image = pygame.image.load('images/ship_2.bmp')
        self.rect = self.image.get_rect()

        self.rect.midright = self.screen_rect.midright

        self.y = float(self.rect.y)

        self.moving_up = False
        self.moving_down = False

    def update(self):
        if self.moving_down and self.y < 750:
            self.y += self.settings.ship_speed
        if self.moving_up and self.y > 0:
            self.y -= self.settings.ship_speed
        self.rect.y = self.y
        
    def blitme(self):
        self.screen.blit(self.image, self.rect)



class Bullet(pygame.sprite.Sprite):
    def __init__(self,ai_game):
        super().__init__()

        self.screen = ai_game.screen
        self.settings = ai_game.settings
        self.color = self.settings.bullet_color 

        self.rect = pygame.Rect(0,0, self.settings.bullet_width, self.settings.bullet_height)
        self.rect.midright = ai_game.ship.rect.midright
        self.x = float(self.rect.x)

    def update(self):
        self.x -= self.settings.bullet_speed
        self.rect.x = self.x

    def draw_bullet(self):
        pygame.draw.rect(self.screen, self.color, self.rect)


class Alien(pygame.sprite.Sprite):
    def __init__(self, ai_game):
        super().__init__()
        self.screen = ai_game.screen
        self.settings = ai_game.settings

        self.image = pygame.image.load('images/alien_2.bmp')
        self.rect = self.image.get_rect()

        # Start each new alien near the top left of the screen.
        self.rect.y = self.rect.width
        self.rect.x = self.rect.height

        # Store the alien's exact horizontal position.
        self.y = float(self.rect.y)

        self.frequency = 1
        self.ySpeed = 0.09
        self.overallY = self.rect.y
        self.amplitude = 4

    def check_edges(self):
        screen_rect = self.screen.get_rect()
        if self.rect.top <= screen_rect.top or self.rect.bottom >= 800:
            return True

    def update(self):
        self.rect.x += (self.settings.alien_speed * self.settings.fleet_direction * self.frequency)

        #you can either comment out the one bellow and use the next two lines
        #or you can leave it as it is.
        #You might also want to change the frequency, ySpeed, amplitude and
        #self.settings.alien_speed values to get it to zigzag exactly how you
        #want it.
        
        self.rect.y = self.overallY + (self.amplitude * math.sin(self.ySpeed * self.rect.x))

##        t = pygame.time.get_ticks() * self.ySpeed % 500
##        self.rect.y = (self.amplitude * math.sin(t)) + self.overallY

class SideShooter:

    def __init__(self):
        pygame.init()
        self.settings = Settings()

        self.screen = pygame.display.set_mode((self.settings.screen_width,self.settings.screen_height))
        pygame.display.set_caption("Alien Invasion")

        self.ship = Ship(self)
        self.bullets = pygame.sprite.Group()
        self.aliens = pygame.sprite.Group()

        self._create_fleet()

    def run_game(self):
        """Start the main loop for the game."""
        while True:
            self._check_events()
            self.ship.update()
            self._update_bullets()
            self._update_aliens()
            self._update_screen()

    def _check_events(self):
        """Respond to keypresses and mouse events."""
        for event in pygame.event.get():
            if event.type == pygame.QUIT:
                sys.exit()
            elif event.type == pygame.KEYDOWN:
                self._check_keydown_events(event)
            elif event.type == pygame.KEYUP:
                self._check_keyup_events(event)

    def _check_keydown_events(self, event):
        """Respond to keypresses."""
        if event.key == pygame.K_UP:
            self.ship.moving_up = True
        elif event.key == pygame.K_DOWN:
            self.ship.moving_down = True
        elif event.key == pygame.K_q:
            sys.exit()
        elif event.key == pygame.K_SPACE:
            self._fire_bullet()

    def _check_keyup_events(self, event):
        """Respond to key releases."""
        if event.key == pygame.K_UP:
            self.ship.moving_up = False
        elif event.key == pygame.K_DOWN:
            self.ship.moving_down = False

    def _fire_bullet(self):
        if len(self.bullets) < self.settings.bullet_allowed:
            new_bullet = Bullet(self)
            self.bullets.add(new_bullet)

    def _update_bullets(self):
        self.bullets.update()

        for bullet in self.bullets.copy():
            if bullet.rect.right <= self.screen.get_rect().left:
                self.bullets.remove(bullet)
        self._check_bullet_detection()         

    def _check_bullet_detection(self):
        collisions = pygame.sprite.groupcollide(self.bullets, self.aliens, True, True)   

        if not self.aliens:
            self.bullets.empty()
            self._create_fleet()


    def _update_aliens(self):
        self._check_fleet_edges()
        self.aliens.update()

    def _create_fleet(self):
        alien = Alien(self)
        alien_width, alien_height = alien.rect.size
        available_space_x = self.settings.screen_width - (2* alien_width)
        number_aliens_x = available_space_x // (3*alien_width)
        

        ship_height = self.ship.rect.height
        available_space_y = (self.settings.screen_height -
                                (3 * alien_height) - ship_height)
        number_rows = available_space_y // (2 * alien_height)
        
        for row_number in range(number_rows):
            for alien_number in range(number_aliens_x):
                self._create_alien(alien_number, row_number)

    def _create_alien(self, alien_number, row_number):
        alien = Alien(self)
        alien_width, alien_height = alien.rect.size
        alien.overallY = alien_width + 2 * alien_width * alien_number
        #alien.rect.y = alien.y
        #self.overallY = alien.y
        alien.rect.x = alien.rect.height + 2 * alien.rect.height * row_number
        self.aliens.add(alien)

    def _check_fleet_edges(self):
        for alien in self.aliens.sprites():
            if alien.check_edges():
                self._change_fleet_direction()
                break
            
    def _change_fleet_direction(self):
        for alien in self.aliens.sprites():
            alien.rect.x += self.settings.fleet_drop_speed
        self.settings.fleet_direction *= -1

    def _update_screen(self):
        self.screen.fill(self.settings.bg_color)
        self.ship.blitme()
        for bullet in self.bullets.sprites():
            bullet.draw_bullet()
        self.aliens.draw(self.screen)

        pygame.display.flip()

ss = SideShooter()
ss.run_game()  

Answer 2

如果我理解你所说的“之字形”是什么意思，有点像锯齿状运动（反复上下移动，同时不断向一侧移动），每个外星人都会沿着这样的路径（结束于 . ):

/\  /\  /\  /\  .
  \/  \/  \/  \/

如果是这种情况，除了 x 轴之外，外星人还需要更新他们的 y 轴。

另一方面，如果您希望 y 坐标保持不变并沿 x 轴向左、向右、向左等移动，那么从您共享的代码中并不清楚这将如何发生。

看起来就像你写的那样，只要一个外星人超出屏幕空间，整个舰队就会改变方向。这可能是需要的，但您可以通过针对每个外星人执行此检查和方向更改来潜在地简化您的代码。

例如，您可以向 Alien 类添加 direction 参数，而不是更改 fleet_direction，并单独更改每个外星人的方向。

这将允许您像这样编写 update_aliens 函数：

for alien in aliens:
  if alien.check_edges():
    alien.direction *= -1
  alien.update()

[编辑]

根据您的 cmets，您可以尝试向您的 Alien.update 函数添加一些额外的 y-update，如下所示：

def __init__(self):
  #...
  self.y_direction = 1
  self.y_counter = 1


def update(self):
  self.rect.x += #...
  self.rect.y += 1
  if self.y_counter == 10: # zig size is 10
    self.y_counter = 0
    self.y_direction *= -1 # change y direction only
  self.y_counter += 1

这类似于另一个答案的正弦建议，但您应该检查边界，以便您的外星人在碰到屏幕边缘时会反转方向。

或者，您可以仅在精灵接触屏幕边缘时应用方向变化：

class Alien(Sprite):
  def __init__(self):
    # ...
    self.x_direction = 1
    self.y_direction = 1

  def _check_edges(self):
    # ...
    if self.rect.y > screen_rect.top or self.rect.y < screen_rect.botttom:
      self.y_direction *= -1
    if self.rect.x > screen_rect.right or self.rect.x < screen_rect.left:
      self.x_direction *= -1

  def update(self):
    # ...
    self.rect.x += self.settings.alien_speed * self.x_direction
    self.rect.y += self.settings.alien_speed * self.y_direction

Answer 3

代码应该按预期工作：

导入系统 导入pygame from pygame.sprite 导入精灵

类设置：

def __init__(self):

    self.screen_width = 1200
    self.screen_height = 800
    self.bg_color = (230, 230, 230)
    self.ship_speed = 1.5

    self.bullet_speed = 1.5
    self.bullet_width = 15
    self.bullet_height = 3
    self.bullet_color = (60, 60, 60)
    self.bullet_allowed = 3

    self.alien_speed = 1
    self.fleet_drop_speed = 10
    self.fleet_direction = 1
    
    

级船：

def __init__(self, ai_game):
    self.screen = ai_game.screen

    self.settings = ai_game.settings

    self.screen_rect = ai_game.screen.get_rect()

    self.image = pygame.image.load('images/ship_2.bmp')
    self.rect = self.image.get_rect()

    self.rect.midright = self.screen_rect.midright

    self.y = float(self.rect.y)

    self.moving_up = False
    self.moving_down = False

def update(self):
    if self.moving_down and self.y < 750:
        self.y += self.settings.ship_speed
    if self.moving_up and self.y > 0:
        self.y -= self.settings.ship_speed
    self.rect.y = self.y     
def blitme(self):
    self.screen.blit(self.image, self.rect) 
   

类子弹（精灵）：

def __init__(self,ai_game):
    super().__init__()

    self.screen = ai_game.screen
    self.settings = ai_game.settings
    self.color = self.settings.bullet_color 

    self.rect = pygame.Rect(0,0, self.settings.bullet_width, self.settings.bullet_height)
    self.rect.midright = ai_game.ship.rect.midright
    self.x = float(self.rect.x)

def update(self):
    self.x -= self.settings.bullet_speed
    self.rect.x = self.x

def draw_bullet(self):
    pygame.draw.rect(self.screen, self.color, self.rect)

类外星人（Sprite）：

def __init__(self, ai_game):
    super().__init__()
    self.screen = ai_game.screen
    self.settings = ai_game.settings

    self.image = pygame.image.load('images/alien_2.bmp')
    self.rect = self.image.get_rect()

    # Start each new alien near the top left of the screen.
    self.rect.y = self.rect.width
    self.rect.x = self.rect.height

    # Store the alien's exact horizontal position.
    self.y = float(self.rect.x)

def check_edges(self):
    screen_rect = self.screen.get_rect()
    if self.rect.top <= screen_rect.top or self.rect.bottom >= 800:
        return True

def update(self):
    self.y += (self.settings.alien_speed *
                    self.settings.fleet_direction)
    self.rect.y = self.y

类 SideShooter：

def __init__(self):
    pygame.init()
    self.settings = Settings()

    self.screen = pygame.display.set_mode((self.settings.screen_width,self.settings.screen_height))
    pygame.display.set_caption("Alien Invasion")

    self.ship = Ship(self)
    self.bullets = pygame.sprite.Group()
    self.aliens = pygame.sprite.Group()

    self._create_fleet()

def run_game(self):
    """Start the main loop for the game."""
    while True:
        self._check_events()
        self.ship.update()
        self._update_bullets()
        self._update_aliens()
        self._update_screen()

def _check_events(self):
    """Respond to keypresses and mouse events."""
    for event in pygame.event.get():
        if event.type == pygame.QUIT:
            sys.exit()
        elif event.type == pygame.KEYDOWN:
            self._check_keydown_events(event)
        elif event.type == pygame.KEYUP:
            self._check_keyup_events(event)

def _check_keydown_events(self, event):
    """Respond to keypresses."""
    if event.key == pygame.K_UP:
        self.ship.moving_up = True
    elif event.key == pygame.K_DOWN:
        self.ship.moving_down = True
    elif event.key == pygame.K_q:
        sys.exit()
    elif event.key == pygame.K_SPACE:
        self._fire_bullet()

def _check_keyup_events(self, event):
    """Respond to key releases."""
    if event.key == pygame.K_UP:
        self.ship.moving_up = False
    elif event.key == pygame.K_DOWN:
        self.ship.moving_down = False

def _fire_bullet(self):
    if len(self.bullets) < self.settings.bullet_allowed:
        new_bullet = Bullet(self)
        self.bullets.add(new_bullet)

def _update_bullets(self):
    self.bullets.update()

    for bullet in self.bullets.copy():
        if bullet.rect.right <= self.screen.get_rect().left:
            self.bullets.remove(bullet)
    self._check_bullet_detection()         

def _check_bullet_detection(self):
    collisions = pygame.sprite.groupcollide(self.bullets, self.aliens, True, True)   

    if not self.aliens:
        self.bullets.empty()
        self._create_fleet()


def _update_aliens(self):
    self._check_fleet_edges()
    self.aliens.update()

def _create_fleet(self):

    alien = Alien(self)
    alien_width, alien_height = alien.rect.size
    available_space_x = self.settings.screen_width - (2* alien_width)
    number_aliens_x = available_space_x // (3*alien_width)
    

    ship_height = self.ship.rect.height
    available_space_y = (self.settings.screen_height -
                            (3 * alien_height) - ship_height)
    number_rows = available_space_y // (2 * alien_height)
    
    for row_number in range(number_rows):
        for alien_number in range(number_aliens_x):
            self._create_alien(alien_number, row_number)

def _create_alien(self, alien_number, row_number):
    alien = Alien(self)
    alien_width, alien_height = alien.rect.size
    alien.y = alien_width + 2 * alien_width * alien_number
    alien.rect.y = alien.y
    alien.rect.x = alien.rect.height + 2 * alien.rect.height * row_number
    self.aliens.add(alien)

def _check_fleet_edges(self):
    for alien in self.aliens.sprites():
        if alien.check_edges():
            self._change_fleet_direction()
            break
        
def _change_fleet_direction(self):
    for alien in self.aliens.sprites():
        alien.rect.x += self.settings.fleet_drop_speed
    self.settings.fleet_direction *= -1

def _update_screen(self):
    self.screen.fill(self.settings.bg_color)
    self.ship.blitme()
    for bullet in self.bullets.sprites():
        bullet.draw_bullet()
    self.aliens.draw(self.screen)

    pygame.display.flip()

如果 name == 'ma​​in'：

ss = SideShooter()

ss.run_game()