<<与孩子一起学编程>>中的“滑雪的人”游戏

最近在学习 Python,看了一本书<<与孩子一起学编程>>英文名是“Computer Programming for Kids and Other Beginners”,感觉挺有意思的。

Capture

书中推荐用 pygame 来编写游戏,我按照书上的程序打了一个滑雪者的小游戏。输入程序花了半小时,调试这个程序差不多花了2个小时。

最后调试通过的程序如下:

import pygame,sys,random

skier_images = ["skier_down.png","skier_right1.png",
                "skier_right2.png","skier_left2.png",
                "skier_left1.png"]

class SkierClass(pygame.sprite.Sprite):
    def __init__(self):
        pygame.sprite.Sprite.__init__(self)
        self.image = pygame.image.load("skier_down.png")
        self.rect = self.image.get_rect()
        self.rect.center = [320,100]
        self.angle =0

    def turn(self,direction):
        self.angle = self.angle + direction
        if self.angle < -2: self.angle = -2
        if self.angle >  2: self.angle = 2
        center = self.rect.center
        self.image = pygame.image.load(skier_images[self.angle])
        self.rect = self.image.get_rect()
        self.rect.center =center
        speed = [self.angle,6 - abs(self.angle) * 2]
        return speed

    def move(self,speed):
        self.rect.centerx = self.rect.centerx + speed[0]
        if self.rect.centerx < 20: self.rect.centerx = 20
        if self.rect.centerx > 620: self.rect.centerx =620

class ObstacleClass(pygame.sprite.Sprite):
    def __init__(self,image_file,location,type):
        pygame.sprite.Sprite.__init__(self)
        self.image_file = image_file
        self.image = pygame.image.load(image_file)
        self.location = location
        self.rect = self.image.get_rect()
        self.rect.center = location
        self.type =type
        self.passed =False

    def scroll(self, t_ptr):
        self.rect.centery = self.location[1] - t_ptr

def create_map(start, end):
        obstacles = pygame.sprite.Group()
        gates = pygame.sprite.Group()
        locations = []
        for i in range(10):
            row = random.randint(start,end)
            col = random.randint(0,9)
            location = [col * 64+20,row * 64 +20]
            if not (location in locations):
                locations.append(location)
            type = random.choice(["tree","flag"])
            if type == "tree": img = "skier_tree.png"
            elif type == "flag": img ="skier_flag.png"
            obstact = ObstacleClass(img,location,type)
            obstacles.add(obstact)
        return obstacles

def animate():
        screen.fill([255,255,255])
        pygame.display.update(obstacles.draw(screen))
        screen.blit(skier.image, skier.rect)
        screen.blit(score_text,[10,10])
        pygame.display.flip()

def updateObstacleGroup(map0,map1):
        obstacles = pygame.sprite.Group()
        for ob in map0: obstacles.add(ob)
        for ob in map1: obstacles.add(ob)
        return obstacles

pygame.init()
screen = pygame.display.set_mode([640,640])
clock = pygame.time.Clock()
skier = SkierClass()
speed = [0,6]
map_position =0
points=0;
map0 = create_map(20,29)
map1 = create_map(10,19)
activeMap =0;
obstacles = updateObstacleGroup(map0,map1)
font = pygame.font.Font(None,50)
        
while True:
    clock.tick(30)
    for event in pygame.event.get():
        if event.type == pygame.QUIT: sys.exit()
        if event.type == pygame.KEYDOWN:
            if event.key == pygame.K_LEFT:
                    speed = skier.turn(-1)
            elif event.key == pygame.K_RIGHT:
                    speed = skier.turn(1)
    skier.move(speed)
    map_position+=speed[1]

    if map_position >= 640 and activeMap == 0:
            activeMap = 1
            map0 = create_map(20,29)
            obstacles = updateObstacleGroup(map0,map1)
    if map_position>= 1280 and activeMap == 1:
            activeMap = 0
            for ob in map0:
                ob.location[1] = ob.location[1] -1280
            map_position = map_position - 1280
            map1 = create_map(10,19)
            obstacles = updateObstacleGroup(map0,map1)
            
    for obstacle in obstacles:
            obstacle.scroll(map_position)
    hit = pygame.sprite.spritecollide(skier,obstacles,False)
    if hit:
        if hit[0].type == "tree" and not hit[0].passed:
            points = points -100
            skier.image = pygame.image.load("skier_crash.png")
            animate()
            pygame.time.delay(1000)
            skier.image = pygame.image.load("skier_down.png")
            skier.angle = 0
            speed =[0,6]
            hit[0].passed = True
        elif hit[0].type == "flag" and not hit[0].passed:
            points +=10
            obstacles.remove(hit[0])
    score_text = font.render("Score: "+str(points),1,(0,0,0))
    animate()

 

运行结果:

Untitled

如果你也恰好阅读这本书,遇到同样的问题,建议你参考上面的程序,此外需要特别注意的是 Python 使用缩进之类的来表示上下文之间的隶属关系。如果你的程序遇到莫名其妙的错误,请检查是不是缩进搞错了。比如:

class x:
def func1
def func2

这样,func2 是 x 的一个方法了,如果你在其他地方试图直接调用 func2 就会出现未定 func2 的问题。我因为这样的事情被卡了很久。

最后放上完整的代码(包括官方网站下载到的官方板的源程序),如果你调试不过,最后还可以用beyond compare 这样的对比工具找到原因。

skier

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