Python 游戏编程入门：使用 Pygame 实现图形绘制与动画

while True:
    for event in pygame.event.get():
        if event.type == QUIT or event.type == KEYDOWN:
            import sys
            sys.exit()
    
    # 在此处更新游戏状态和绘制画面
    pygame.display.update()

注意：原代码中常见的错误如 event.typeQUIT 应修正为 event.type == QUIT；screen.display.update() 应修正为 pygame.display.update()。

5. 绘图函数详解

5.1 绘制圆形

# pygame.draw.circle(screen, color, position, radius, width)
pygame.draw.circle(screen, (255, 0, 0), (300, 250), 50, 2)

• color: 颜色元组
• position: 圆心坐标 (x, y)
• radius: 半径
• width: 线条宽度，0 表示填充

5.2 绘制矩形

# pygame.draw.rect(screen, color, rect, width)
# rect: (x, y, width, height)
pos = (100, 100, 100, 100)
pygame.draw.rect(screen, (0, 255, 0), pos, 0)

5.3 绘制线条

# pygame.draw.line(screen, color, start_pos, end_pos, width)
pygame.draw.line(screen, (0, 0, 255), (0, 0), (100, 100), 2)

5.4 绘制弧形

import math
# pygame.draw.arc(screen, color, rect, start_angle, end_angle, width)
# position: (x, y, w, h) 定义外接矩形
start_angle = math.radians(0)
end_angle = math.radians(90)
pygame.draw.arc(screen, (255, 255, 0), (200, 200, 100, 100), start_angle, end_angle, 2)

角度从正右侧开始逆时针旋转，0 到 360 度。

6. 示例一：移动矩形

此示例演示了如何在循环中更新位置、检测边界碰撞并改变颜色。

import sys
import random
import pygame
from pygame.locals import *

pygame.init()
screen = pygame.display.set_mode((600, 500))
pygame.display.set_caption("Drawing Rectangles")

pos_x = 300
pos_y = 250
vel_x = 2
vel_y = 1
rand1, rand2, rand3 = random.randint(0, 255), random.randint(0, 255), random.randint(0, 255)
color = (rand1, rand2, rand3)

while True:
    for event in pygame.event.get():
        if event.type in (QUIT, KEYDOWN):
            sys.exit()

    screen.fill((0, 0, 200))
    
    pos_x += vel_x
    pos_y += vel_y
    
    # 水平边界检测
    if pos_x > 500 or pos_x < 0:
        vel_x = -vel_x
        rand1, rand2, rand3 = random.randint(0, 255), random.randint(0, 255), random.randint(0, 255)
        color = (rand1, rand2, rand3)
    
    # 垂直边界检测
    if pos_y > 400 or pos_y < 0:
        vel_y = -vel_y
        rand1, rand2, rand3 = random.randint(0, 255), random.randint(0, 255), random.randint(0, 255)
        color = (rand1, rand2, rand3)
    
    width = 0
    pos = (pos_x, pos_y, 100, 100)
    pygame.draw.rect(screen, color, pos, width)
    
    pygame.display.update()

7. 示例二：Pie 游戏

此示例演示了如何根据按键状态绘制不同的扇形区域。

import sys
import math
import pygame
from pygame.locals import *

pygame.init()
screen = pygame.display.set_mode((600, 500))
pygame.display.set_caption("The Pie Game")
myfont = pygame.font.Font(None, 60)

color = (200, 80, 60)
width = 4
x, y = 300, 250
radius = 200
position = (x - radius, y - radius, radius * 2, radius * 2)

piece1 = piece2 = piece3 = piece4 = False

while True:
    for event in pygame.event.get():
        if event.type == QUIT:
            sys.exit()
        elif event.type == KEYUP:
            if event.key == pygame.K_ESCAPE:
                sys.exit()
            elif event.key == pygame.K_1:
                piece1 = True
            elif event.key == pygame.K_2:
                piece2 = True
            elif event.key == pygame.K_3:
                piece3 = True
            elif event.key == pygame.K_4:
                piece4 = True

    screen.fill((0, 0, 200))
    
    # 绘制数字提示
    textimage1 = myfont.render("1", True, color)
    screen.blit(textimage1, (x + radius / 2 - 20, y - radius / 2))
    textimage2 = myfont.render("2", True, color)
    screen.blit(textimage2, (x - radius / 2, y - radius / 2))
    textimage3 = myfont.render("3", True, color)
    screen.blit(textimage3, (x - radius / 2, y + radius / 2 - 20))
    textimage4 = myfont.render("4", True, color)
    screen.blit(textimage4, (x + radius / 2 - 20, y + radius / 2 - 20))
    
    # 根据状态绘制扇形
    if piece1:
        pygame.draw.arc(screen, color, position, math.radians(0), math.radians(90), width)
        pygame.draw.line(screen, color, (x, y), (x + radius, y), width)
        pygame.draw.line(screen, color, (x, y), (x, y - radius), width)
    
    if piece2:
        pygame.draw.arc(screen, color, position, math.radians(90), math.radians(180), width)
        pygame.draw.line(screen, color, (x, y), (x, y - radius), width)
        pygame.draw.line(screen, color, (x, y), (x - radius, y), width)
    
    if piece3:
        pygame.draw.arc(screen, color, position, math.radians(180), math.radians(270), width)
        pygame.draw.line(screen, color, (x, y), (x - radius, y), width)
        pygame.draw.line(screen, color, (x, y), (x, y + radius), width)
    
    if piece4:
        pygame.draw.arc(screen, color, position, math.radians(270), math.radians(360), width)
        pygame.draw.line(screen, color, (x, y), (x, y + radius), width)
        pygame.draw.line(screen, color, (x, y), (x + radius, y), width)
      
    # 全部完成时变绿
    if piece1 and piece2 and piece3 and piece4:
        color = (0, 255, 0)
    
    pygame.display.update()

8. 挑战练习

8.1 绘制椭圆

使用 pygame.draw.ellipse 函数，其参数结构与 rect 类似，接受 (x, y, width, height) 定义的矩形区域。

8.2 随机绘制线条

在循环外绘制一次图形，则图形保持不变；在 while True 循环内绘制，则每帧都会重绘。这有助于理解渲染循环的机制。

import random
import sys
import pygame
from pygame.locals import *

pygame.init()
screen = pygame.display.set_mode((800, 600))

for i in range(1000):
    x1, y1 = random.randint(0, 800), random.randint(0, 600)
    x2, y2 = random.randint(0, 800), random.randint(0, 600)
    pygame.draw.line(screen, (100, 255, 200), (x1, y1), (x2, y2), 2)

while True:
    for event in pygame.event.get():
        if event.type in (QUIT, KEYDOWN):
            sys.exit()
    pygame.display.update()

总结

Pygame 提供了丰富的接口来处理图形界面和游戏逻辑。掌握初始化、事件循环、绘图 API 以及数学计算（如弧度转换）是入门的关键。建议初学者多尝试修改示例中的参数，观察变化，逐步构建自己的小游戏项目。