python从入门到实践　第１２章　武装飞船　之　调整飞船的速度程序实践_python编程飞船速度代码

第一个文件，ｍａｉｎ．ｐｙ是主程序 

＃main.py
import sys
import pygame
from settings import Settings
from ship     import Ship
import update as pt
def run_game():
    my_set = Settings()
    
    pygame.init()
    screen = pygame.display.set_mode(my_set.set_mode)
    my_ship = Ship(screen,my_set)
    pygame.display.set_caption(my_set.set_caption)
    while True:
        pt.update(my_ship,screen,my_set)
run_game()

第二个文件：settings.py

class Settings():
    def __init__(self):
        self.color = (255,255,255)
        self.set_mode = (1000,800)
        self.new_speed_factor = 1.5
        self.set_caption = 'ship invasion'

第三个文件：update.py

#update.py
import pygame
import sys
def check_events(ship):
    for event in pygame.event.get():
        if event.type == pygame.QUIT:
            sys.exit()
        elif event.type == pygame.KEYDOWN:
            if event.key == pygame.K_RIGHT:
                ship.moving_right = True
            if event.key == pygame.K_LEFT:
                ship.moving_left = True
            if event.key == pygame.K_UP:
                ship.moving_up = True
            if event.key == pygame.K_DOWN:
                ship.moving_down = True
        elif event.type == pygame.KEYUP:
            if event.key == pygame.K_RIGHT:
                ship.moving_right = False
            if event.key == pygame.K_LEFT:
                ship.moving_left = False
            if event.key == pygame.K_UP:
                ship.moving_up = False
            if event.key == pygame.K_DOWN:
                ship.moving_down = False
def update(ship,screen,settings):
    check_events(ship)
    ship.update()
    #特别要注意：填充颜色的下面这句话一定要在绘图之前进行（也就是要放在ship.blitme之前，否则
    #颜色会覆盖掉前面的绘好的图形）
    screen.fill(settings.color)
    ship.blitme()
    pygame.display.flip()

第四个文件：ｓｈｉｐ．ｐｙ

import pygame
import sys
class Ship():
    def __init__(self,screen,settings):
        self.settings = settings
        self.screen = screen
        self.image  = pygame.image.load("ship.bmp")
        self.rect   = self.image.get_rect()
        self.screen_rect = self.screen.get_rect()
        
        self.rect.centerx = self.screen_rect.centerx
        self.rect.bottom  = self.screen_rect.bottom
        self.center = float(self.rect.centerx)
        self.moving_left = False
        self.moving_right = False
        self.moving_up  = False
        self.moving_down = False
    def blitme(self):
        self.screen.blit(self.image,self.rect)
    def update(self):
        if self.moving_right == True:
            self.center += self.settings.new_speed_factor
        if self.moving_left  == True:
            self.center -= self.settings.new_speed_factor
        if self.moving_up    == True:
            self.rect.bottom -= 1
        if self.moving_down == True:
            self.rect.bottom += 1
        self.rect.centerx = self.center

本文所用到的ship.bmp和alien.bmp的下载   链接: https://pan.baidu.com/s/1Dn5yaQGZLIsN0BohM8PzoA  密码: 38ie

注：以上程序只是提高了横向的速度，纵向移动速度并没有改变，如果要改变纵向移动速度，必须改变ｓｈｉｐ．ｐｙ文件，自己改动的代码如下（其它文件不变）：

import pygame
import sys
class Ship():
    def __init__(self,screen,settings):
        self.settings = settings
        self.screen = screen
        self.image  = pygame.image.load("ship.bmp")
        self.rect   = self.image.get_rect()
        self.screen_rect = self.screen.get_rect()
        
        self.rect.centerx = self.screen_rect.centerx
        self.rect.bottom  = self.screen_rect.bottom
        self.center_x = float(self.rect.centerx)
        self.center_y = float(self.rect.bottom)
        self.moving_left = False
        self.moving_right = False
        self.moving_up  = False
        self.moving_down = False
    def blitme(self):
        self.screen.blit(self.image,self.rect)
    def update(self):
        if self.moving_right == True:
            self.center_x += self.settings.new_speed_factor
        if self.moving_left  == True:
            self.center_x -= self.settings.new_speed_factor
        if self.moving_up    == True:
            self.center_y -= self.settings.new_speed_factor
        if self.moving_down == True:
            self.center_y += self.settings.new_speed_factor
        self.rect.centerx = self.center_x
        self.rect.bottom  = self.center_y

随着代码越来越长，我们队update.py文件进行重构，把check_events()的部分代码放在不同的文件中,update.py文件重新布置代码如下：

import pygame
import sys
def check_keydown_events(event,ship):
    if event.type == pygame.KEYDOWN:
        if event.key == pygame.K_RIGHT:
            ship.moving_right = True
        if event.key == pygame.K_LEFT:
            ship.moving_left = True
        if event.key == pygame.K_UP:
            ship.moving_up = True
        if event.key == pygame.K_DOWN:
            ship.moving_down = True
def check_keyup_events(event,ship):
    if event.type == pygame.KEYUP:
        if event.key == pygame.K_RIGHT:
            ship.moving_right = False
        if event.key == pygame.K_LEFT:
            ship.moving_left = False
        if event.key == pygame.K_UP:
            ship.moving_up = False
        if event.key == pygame.K_DOWN:
            ship.moving_down = False
def check_events(ship):
    for event in pygame.event.get():
        if event.type == pygame.QUIT:
            sys.exit()
        elif event.type == pygame.KEYDOWN:
#因为上面已经定义过函数check_keydown_events，所以可以直接使用
            check_keydown_events(event,ship)
        elif event.type == pygame.KEYUP:
#因为上面已经定义过函数check_up_events，所以下面也可以直接使用
            check_keyup_events(event,ship)
def update(ship,screen,settings):
    check_events(ship)
    ship.update()
    screen.fill(settings.color)
    ship.blitme()
    pygame.display.flip()

注意：在update.py文件中，的update函数里，ｓｃｒｅｅｎ．ｆｉｌｌ函数一定要放在ｂｌｉｔｍｅ函数之前，否则颜色会覆盖掉绘好的图形，也就是尽早填充颜色