pygame 飞机大战动态画面的实现方式（二）精灵类的实现方式

目标：用sprite 类来实现动态画面，例如爆炸效果，BOSS机的炫酷展示

用了python游戏编程入门里的例题，改变了一下。

load 函数加载一张图片，对指定高宽，列的图片切割存

update 函数每次更新都计算，大于刷新间隔，就显示下一张图片，刷完图片又从第一张开始

set_pos 函数可以设置图片在屏幕中显示的位置

import pygame
from pygame.locals import *

class Blast(pygame.sprite.Sprite):
    def __init__(self, scene):
        pygame.sprite.Sprite.__init__(self)
        self.main_scene = scene
        self.image = None
        self.master_image = None
        self.rect = None
        self.topleft = 0,0
        self.frame = 0
        self.old_frame = -1
        self.frame_width = 1
        self.frame_height = 1
        self.first_frame = 0
        self.last_frame = 0
        self.columns = 1
        self.last_time = pygame.time.get_ticks()
        self.rate = 60

    def load(self, filename, width, height, columns):
        self.master_image = pygame.image.load(filename).convert_alpha()
        self.frame_width = width
        self.frame_height = height
        self.rect = self.master_image.get_rect()
        self.columns = columns
        rect = self.master_image.get_rect()
        self.last_frame = (rect.width // width) * (rect.height // height) - 1
    
    def set_pos(self,x,y):
        self.rect.x = x
        self.rect.y = y

    def update(self):
        current_time = pygame.time.get_ticks()
        if current_time > self.last_time + self.rate:
            self.frame += 1
            if self.frame > self.last_frame:
                self.frame = self.first_frame
            self.last_time = current_time

        if self.frame != self.old_frame:
            frame_x = (self.frame % self.columns) * self.frame_width
            frame_y = (self.frame // self.columns) * self.frame_height
            rect = ( frame_x, frame_y, self.frame_width, self.frame_height )
            self.image = self.master_image.subsurface(rect)
            self.old_frame = self.frame
     

显示代码如下：
 

pygame.init()
screen = pygame.display.set_mode((800,600),0,32)
pygame.display.set_caption("精灵类测试")
font = pygame.font.Font(None, 18)
framerate = pygame.time.Clock()


blast = Blast(screen)
blast.load('blast0.png',77,72,6)
group = pygame.sprite.Group()
blast.set_pos(200,220)
group.add(blast)

while True:
   
    for event in pygame.event.get():
        if event.type == pygame.QUIT:
            pygame.quit()
            exit()
    key = pygame.key.get_pressed()
    if key[pygame.K_ESCAPE]:
        exit()
        
    screen.fill((0,0,0))

    group.update()
    group.draw(screen)
    pygame.display.update()

火焰效果就出来了。blast0.png  为一张 77*6宽,72高，切割6个小图的图

可以用self.last_time > 2000 :

                 self.kill()

爆炸效果两秒后消失