如何在 pygame 程序中获得评分功能？

Question

我一直在尝试在我尝试制作的简单游戏中用变量记录分数。 当子弹和外星人（代码中的敌人）之间的距离小于某个值（这里是 20 个单位）时，分数会增加。

然而，当我用子弹击中外星人时，分数并没有增加。我该怎么办？

import pygame
import random
import math

# for initialising pygame (req for every pygame app)
pygame.init()

# making the basic window (dimensions must be written inside a tuple )
screen = pygame.display.set_mode((500, 500))

# background
background = pygame.image.load('C:/Users/aryan/Downloads/background.jpg')

# load and set the logo
logo = pygame.image.load('C:/Users/aryan/Downloads/bp.png')  # directory of logo
pygame.display.set_icon(logo)
pygame.display.set_caption("space wars")  # program name

# define a variable to control the main loop
running = True

# player
playerimg = pygame.image.load('C:/Users/aryan/Downloads/spaceship.png')
playerX = 218  # x and y coordinates of image
playerY = 350
playerxchange = 0  # this will be the change in movement in x direction of our image
playerychange = 0  # this will be the change in movement in y direction of our image


def player(x, y):
    screen.blit(playerimg, (x, y))  # blit draws our image on the surface(basically the background)
    # syntax for blit(imagename, (xcoordinate,ycoordinate))


# enemy
enemyimg = pygame.image.load('C:/Users/aryan/Downloads/enemy.png')
enemyX = random.randint(0, 476)
enemyY = 20
enemyxchange = 0.2
enemyychange = 40

# game over
overimg = pygame.image.load('C:/Users/aryan/Downloads/gameover.png')

# bullet
bulletimg = pygame.image.load('C:/Users/aryan/Downloads/bullet.png')
bulletX = 0
bulletY = 350
bulletxchange = 0
bulletychange = 1
bullet_state = "ready"              # "ready" you cant see bullet on screen
                                    # "fire" you can see bullet firing

bullets = []  # Array to store the position of the bullets

score = 0

def enemy(x, y):
    screen.blit(enemyimg, (x, y))  # blit draws our image on the surface(basically the background)
    # syntax for blit(imagename, (xcoordinate,ycoordinate))


def firebullet(x, y):
    global bullet_state
    bullet_state = "ready"
    bullets.append([x + 12, y + 6]) # Creating a new bullet


def iscollision(enemyX, enemyY, bulletX, bulletY):
    distance = math.sqrt(math.pow(enemyX-bulletX, 2)+ math.pow(enemyY-bulletY,2))     # distance formula
    if distance <= 20:
        return True
    else:
        return False



# main loop
while running:
    screen.fill((120, 120, 120))  # in order (r, g, b) . (0, 0, 0) is black (255, 0, 0) is red...
    screen.blit(background, (0, 0))
    # event handling, gets all event from the event queue
    for event in pygame.event.get():
        # only do something if the event is of type QUIT
        if event.type == pygame.QUIT:
            # change the value to False, to exit the main loop
            running = False

        # checking keystroke
        if event.type == pygame.KEYDOWN:
            if event.key == pygame.K_RIGHT:
                playerxchange += 0.2  # change in movement will be 0.2 towards the right
            if event.key == pygame.K_LEFT:
                playerxchange -= 0.2  # change in movement will be 0.2 towards the right
            if event.key == pygame.K_UP:
                playerychange -= 0.2
            if event.key == pygame.K_DOWN:
               playerychange += 0.2
            if event.key == pygame.K_SPACE:
                bullet_state = "fire"
                firebullet(playerX, playerY)
        if event.type == pygame.KEYUP:
            if event.key == pygame.K_LEFT or event.key == pygame.K_RIGHT or event.key == pygame.K_DOWN or event.key == pygame.K_UP:
                playerxchange = 0
                playerychange = 0

    playerY += playerychange
    playerX += playerxchange  # the value of playerx changes by +- 0.1 depending on keystroke

    if playerX <= -64:  # this teleports the spaceship from left end to right end
        playerX = 564
    elif playerX >= 564:  # this teleports spaceship from right end to left
        playerX = -64

    if playerY >= 436:  # this prevents spaceship from leaving vertically
        playerY = 436
    if playerY <= 0:
        playerY = 0

    # enemy movement
    enemyX += enemyxchange

    if enemyY >= 476:
        enemyY = 476
        enemyYchange = 0
        enemyXchange = 0

    if enemyX <= 0:
        enemyxchange = 0.1
        enemyY += enemyychange
    elif enemyX >= 465:
        enemyxchange = -0.1
        enemyY += enemyychange

    # bullet movement
    if bullet_state is "fire":
        firebullet(playerX, playerY)


    for bullet in bullets:
        screen.blit(bulletimg, (bullet[0], bullet[1]))  # Print a bullet
        bullet[0] -= bulletxchange  # Updates its position
        bullet[1] -= bulletychange
        if bullet[1] < 0:
            bullets.remove(bullet)

    # collision
    collision = iscollision(enemyX, enemyY, bulletX, bulletY)
    if collision:
        score += 1

    player(playerX, playerY)  # player method is called AFTER screen.fill otherwise the screen will fill after image has been blitted
    enemy(enemyX, enemyY)

    pygame.display.update()  # necessary for events to keep updating

Answer 1

您需要测试子弹的实际位置。使用 for 循环遍历列表中的所有项目符号。测试单个子弹是否与循环内的敌人发生碰撞。当子弹与敌人发生碰撞时，将其从列表中移除。因此，列表 (bullets[:]) 的副本必须 运行 通过（参见 How to remove items from a list while iterating?）：

while running:
    # [...]

    # collision

    #collision = iscollision(enemyX, enemyY, bulletX, bulletY) DELETE
    #if collision:                                             DELETE
    #    score += 1                                            DELETE 

    # ADD
    for bullet in bullets[:]:
        collision = iscollision(enemyX, enemyY, bullet[0], bullet[1])
        if collision:
            score += 1
            print(score)
            bullets.remove(bullet)

如果你不取出子弹，它会连续帧数次击中敌人，分数会增加数倍。或者你可以移除敌人或敌人和子弹。

---

使用pygame.Rect objects and colliderect()检测2个对象或2个图像的边界矩形之间的碰撞：
（参见 ）

def iscollision(enemyX, enemyY, bulletX, bulletY):
    bullet_rect = bulletimg.get_rect(topleft = (bulletX, bulletY))
    enemy_rect = enemyimg.get_rect(topleft = (enemyX, enemyY))
    return bullet_rect.colliderect(enemy_rect)