【转载】pygame的斜线运动

pygame是用来写2D游戏的。

实现斜线运动，无非是在x和y两个方向上分运动的合成。x方向上的运动，当撞到边界的时候取相反速度就好了。

这里是用网球王子中的图片，以及一个网球实现，效果截图：

注意看，那个方块形状的网球是会动的，撞到边界就反弹，时刻匀速（这情况太理想了。。。）

代码：

# coding:utf-8
bgimg = 'teni.jpg'
spimg = 'ball.jpg'

import pygame
from pygame.locals import *
from sys import exit

pygame.init()
screen = pygame.display.set_mode((640, 480), 0, 32)

bg = pygame.image.load(bgimg).convert()
sp = pygame.image.load(spimg).convert_alpha()

clock = pygame.time.Clock()

x, y =100., 100.
speed_x, speed_y = 133., 170.

while True:
    for event in pygame.event.get():
        if event.type == QUIT:
            exit()

    screen.blit(bg, (0, 0))
    screen.blit(sp, (x, y))

    time_passed = clock.tick(30)  # 设定最大FPS不超过30
    # FPS：Frame per second
    time_passed_seconds = time_passed / 1000.0

    x += speed_x * time_passed_seconds
    y += speed_y * time_passed_seconds

    if x > 640 - sp.get_width():
        speed_x = -speed_x
        x = 640 - sp.get_width()
    elif x < 0:
        speed_x = - speed_x
        x = 0.

    if y > 480 - sp.get_height():
        speed_y = -speed_y
        y = 480 - sp.get_height()
    elif y < 0:
        speed_y = -speed_y
        y = 0

    pygame.display.update()