Python教程-如何用Python开发游戏

Python是一种非常多用途的编程语言，在各个领域都有广泛的应用，包括Web开发、机器学习、人工智能、GUI应用程序以及游戏开发。

Python提供了一个名为pygame的内置库，用于游戏开发。一旦我们了解了Python编程的基本概念，就可以使用pygame库创建具有引人注目的图形、适当动画和声音的游戏。

Pygame是一个跨平台的库，用于设计视频游戏。它包括计算机图形和声音库，为用户提供了标准的游戏体验。

它由Pete Shinners开发，用于替代PySDL。

Pygame的先决条件

要学习pygame，我们必须先了解Python编程语言。

安装Pygame

打开命令行终端，输入以下命令来安装pygame。

pip install pygame  

我们也可以通过IDE来安装它。

简单的Pygame示例

以下是创建一个简单pygame窗口的示例。

import pygame    
    
pygame.init()    
screen = pygame.display.set_mode((400,500))    
done = False    
    
while not done:    
    for event in pygame.event.get():    
        if event.type == pygame.QUIT:    
            done = True    
    pygame.display.flip()

输出:

所有图形都将绘制在pygame窗口中。

让我们了解上述程序的基本语法。

import pygame - 这是一个允许我们使用pygame所有功能的模块。

pygame.init() - 用于初始化pygame的所有必需模块。

pygame.display.set_mode((width, height)) - 用于调整窗口大小。它将返回一个表面对象。表面对象用于执行图形操作。

pygame.event.get() - 清空事件队列。如果不调用它，窗口消息将开始堆积，操作系统将认为游戏无响应。

pygame.QUIT - 用于关闭窗口角落的关闭按钮时，用于解除事件。

pygame.display.flip() - 用于反映游戏的任何更新。如果进行任何更改，我们需要调用display.flip()函数。

我们可以在pygame表面上绘制任何形状，包括添加图像和吸引人的字体。Pygame提供了许多内置函数来在屏幕上绘制几何形状。这些形状是开发游戏的初始阶段。

让我们了解如何在屏幕上绘制形状的以下示例。

示例 -

import pygame    
from math import pi    
pygame.init()    
# size variable is using for set screen size    
size = [400, 300]    
screen = pygame.display.set_mode(size)    
pygame.display.set_caption("Example program to draw geometry")    
# done variable is using as flag     
done = False    
clock = pygame.time.Clock()    
while not done:    
    # clock.tick() limits the while loop to a max of 10 times per second.    
        clock.tick(10)    
    
    for event in pygame.event.get():  # User did something    
        if event.type == pygame.QUIT:  # If user clicked on close symbol     
            done = True  # done variable that we are complete, so we exit this loop    
    
    # All drawing code occurs after the for loop and but    
    # inside the main while done==False loop.    
    
    # Clear the default screen background and set the white screen background    
    screen.fill((0, 0, 0))    
    
    # Draw on the screen a green line which is 5 pixels wide.    
    pygame.draw.line(screen, (0, 255, 0), [0, 0], [50, 30], 5)    
    # Draw on the screen a green line which is 5 pixels wide.    
    pygame.draw.lines(screen, (0, 0, 0), False, [[0, 80], [50, 90], [200, 80], [220, 30]], 5)    
    
    # Draw a rectangle outline    
    pygame.draw.rect(screen, (0, 0, 0), [75, 10, 50, 20], 2)    
    
    # Draw a solid rectangle    
    pygame.draw.rect(screen, (0, 0, 0), [150, 10, 50, 20])    
    
    # This draw an ellipse outline, using a rectangle as the outside boundaries    
    pygame.draw.ellipse(screen, (255, 0, 0), [225, 10, 50, 20], 2)    
    
    # This draw a solid ellipse, using a rectangle as the outside boundaries    
    pygame.draw.ellipse(screen, (255, 0, 0), [300, 10, 50, 20])    
    
    # Draw a triangle using the polygon function    
    pygame.draw.polygon(screen, (0, 0, 0), [[100, 100], [0, 200], [200, 200]], 5)    
    
    # This draw a circle    
    pygame.draw.circle(screen, (0, 0, 255), [60, 250], 40)    
    
    # This draw an arc    
    pygame.draw.arc(screen, (0, 0, 0), [210, 75, 150, 125], 0, pi / 2, 2)    
    
    # This function must write after all the other drawing commands.    
    pygame.display.flip()    
    
# Quite the execution when clicking on close    
pygame.quit()    

输出:

解释 -

在上面的示例中，我们绘制了不同的形状，如三角形、直线、矩形、椭圆、圆、弧、实心圆和椭圆。我们根据形状使用了pygame.draw函数，并提供了合适的参数。

示例 - 使用Pygame开发贪吃蛇游戏

程序 -

# Snake Tutorial Using Pygame   
  
import math  
import random  
import pygame  
import tkinter as tk  
from tkinter import messagebox  
  
  
class cube(object):  
    rows = 20  
    w = 500  
  
    def __init__(self, start, dirnx=1, dirny=0, color=(255, 0, 0)):  
        self.pos = start  
        self.dirnx = 1  
        self.dirny = 0  
        self.color = color  
  
    def move(self, dirnx, dirny):  
        self.dirnx = dirnx  
        self.dirny = dirny  
        self.pos = (self.pos[0] + self.dirnx, self.pos[1] + self.dirny)  
  
    def draw(self, surface, eyes=False):  
        dis = self.w // self.rows  
        i = self.pos[0]  
        j = self.pos[1]  
  
        pygame.draw.rect(surface, self.color, (i * dis + 1, j * dis + 1, dis - 2, dis - 2))  
        if eyes:  
            centre = dis // 2  
            radius = 3  
            circleMiddle = (i * dis + centre - radius, j * dis + 8)  
            circleMiddle2 = (i * dis + dis - radius * 2, j * dis + 8)  
            pygame.draw.circle(surface, (0, 0, 0), circleMiddle, radius)  
            pygame.draw.circle(surface, (0, 0, 0), circleMiddle2, radius)  
  
# This class is defined for snake design and its movement  
class snake(object):  
    body = []  
    turns = {}  
  
    def __init__(self, color, pos):  
        self.color = color  
        self.head = cube(pos)  
        self.body.append(self.head)  
        self.dirnx = 0  
        self.dirny = 1  
  
    def move(self):  
        for event in pygame.event.get():  
            if event.type == pygame.QUIT:  
                pygame.quit()  
  
            keys = pygame.key.get_pressed()  
            # It will manage the keys movement for the snake  
            for key in keys:  
                if keys[pygame.K_LEFT]:  
                    self.dirnx = -1  
                    self.dirny = 0  
                    self.turns[self.head.pos[:]] = [self.dirnx, self.dirny]  
  
                elif keys[pygame.K_RIGHT]:  
                    self.dirnx = 1  
                    self.dirny = 0  
                    self.turns[self.head.pos[:]] = [self.dirnx, self.dirny]  
  
                elif keys[pygame.K_UP]:  
                    self.dirnx = 0  
                    self.dirny = -1  
                    self.turns[self.head.pos[:]] = [self.dirnx, self.dirny]  
  
                elif keys[pygame.K_DOWN]:  
                    self.dirnx = 0  
                    self.dirny = 1  
                    self.turns[self.head.pos[:]] = [self.dirnx, self.dirny]  
        # Snake when hit the boundary wall  
        for i, c in enumerate(self.body):  
            p = c.pos[:]  
            if p in self.turns:  
                turn = self.turns[p]  
                c.move(turn[0], turn[1])  
                if i == len(self.body) - 1:  
                    self.turns.pop(p)  
            else:  
                if c.dirnx == -1 and c.pos[0] <= 0:  
                    c.pos = (c.rows - 1, c.pos[1])  
                elif c.dirnx == 1 and c.pos[0] >= c.rows - 1:  
                    c.pos = (0, c.pos[1])  
                elif c.dirny == 1 and c.pos[1] >= c.rows - 1:  
                    c.pos = (c.pos[0], 0)  
                elif c.dirny == -1 and c.pos[1] <= 0:  
                    c.pos = (c.pos[0], c.rows - 1)  
                else:  
                    c.move(c.dirnx, c.dirny)  
  
    def reset(self, pos):  
        self.head = cube(pos)  
        self.body = []  
        self.body.append(self.head)  
        self.turns = {}  
        self.dirnx = 0  
        self.dirny = 1  
# It will add the new cube in snake tail after every successful score  
    def addCube(self):  
        tail = self.body[-1]  
        dx, dy = tail.dirnx, tail.dirny  
  
        if dx == 1 and dy == 0:  
            self.body.append(cube((tail.pos[0] - 1, tail.pos[1])))  
        elif dx == -1 and dy == 0:  
            self.body.append(cube((tail.pos[0] + 1, tail.pos[1])))  
        elif dx == 0 and dy == 1:  
            self.body.append(cube((tail.pos[0], tail.pos[1] - 1)))  
        elif dx == 0 and dy == -1:  
            self.body.append(cube((tail.pos[0], tail.pos[1] + 1)))  
  
        self.body[-1].dirnx = dx  
        self.body[-1].dirny = dy  
  
    def draw(self, surface):  
        for i, c in enumerate(self.body):  
            if i == 0:  
                c.draw(surface, True)  
            else:  
                c.draw(surface)  
  
  
def drawGrid(w, rows, surface):  
    sizeBtwn = w // rows  
  
    x = 0  
    y = 0  
    for l in range(rows):  
        x = x + sizeBtwn  
        y = y + sizeBtwn  
        # draw grid line  
        pygame.draw.line(surface, (255, 255, 255), (x, 0), (x, w))  
        pygame.draw.line(surface, (255, 255, 255), (0, y), (w, y))  
  
# This class define for draw game surface  
def redrawWindow(surface):  
    global rows, width, s, snack  
    # This is used to grid surface  
    surface.fill((0, 0, 0))  
    s.draw(surface)  
    snack.draw(surface)  
    drawGrid(width, rows, surface)  
    pygame.display.update()  
  
  
def randomSnack(rows, item):  
    positions = item.body  
  
    while True:  
        x = random.randrange(rows)  
        y = random.randrange(rows)  
        if len(list(filter(lambda z: z.pos == (x, y), positions))) > 0:  
            continue  
        else:  
            break  
  
    return (x, y)  
  
# Using Tkinter function to display message  
def message_box(subject, content):  
    root = tk.Tk()  
    root.attributes("-topmost", True)  
    root.withdraw()  
    messagebox.showinfo(subject, content)  
    try:  
        root.destroy()  
    except:  
        pass  
  
# main() function  
def main():  
    global width, rows, s, snack  
    width = 500  
    rows = 20  
    win = pygame.display.set_mode((width, width))  
    s = snake((255, 0, 0), (10, 10))  
    snack = cube(randomSnack(rows, s), color=(0, 255, 0))  
    flag = True  
  
    clock = pygame.time.Clock()  
  
    while flag:  
        pygame.time.delay(50)  
        clock.tick(10)  
        s.move()  
        if s.body[0].pos == snack.pos:  
            s.addCube()  
            snack = cube(randomSnack(rows, s), color=(0, 255, 0))  
  
        for x in range(len(s.body)):  
            if s.body[x].pos in list(map(lambda z: z.pos, s.body[x + 1:])):  
                print('Score: \n', len(s.body))  
                message_box('You Lost!\n', 'Play again...\n')  
                s.reset((10, 10))  
                break  
  
        redrawWindow(win)  
  
    pass  
  
  
main()  

输出:

如果蛇碰到自己，游戏将终止并显示以下消息。

点击“确定”按钮可以再次玩游戏。我们可以在Pycharm终端中看到分数（我们使用了Pycharm IDE；你可以使用任何Python IDE）。

复制上面的代码并将其粘贴到你的IDE中，然后尽情玩耍。