用鼠标旋转图像

这里涉及的到图像旋转后，方向的计算。我也不是很明白。先记录下来再说。

#_*_coding:utf-8 _*_import pygame
from pygame.locals import *
from sys import exit
from gameobjects.vector2 import Vector2
from math import *background_image_filename='./images/sea.jpg'
sprite_image_filename='./images/fish.png'import pygame
from pygame.locals import *
from sys import exit
pygame.init()
# 让pygame完全控制鼠标
pygame.mouse.set_visible(False)
pygame.event.set_grab(True)screen=pygame.display.set_mode((640,480),0,32)
background=pygame.image.load(background_image_filename).convert()
sprite=pygame.image.load(sprite_image_filename)
clock=pygame.time.Clock()sprite_pos = Vector2(200, 150)   # 初始位置
sprite_speed = 300.     # 每秒前进的像素数（速度）
sprite_rotation = 0.      # 初始角度
sprite_rotation_speed = 360. # 每秒转动的角度数（转速）while True:for event in pygame.event.get():if event.type == QUIT:exit()pressed_keys = pygame.key.get_pressed()rotation_direction = 0.movement_direction = 0.# 通过移动偏移量计算转动rotation_direction = pygame.mouse.get_rel()[0]/5.0#更改角度if pressed_keys[K_LEFT]:rotation_direction+=1if pressed_keys[K_RIGHT]:rotation_direction-=1#前进 后退if pressed_keys[K_UP]:movement_direction+=1if pressed_keys[K_DOWN]:movement_direction-=1screen.blit(background,(0,0))#获得一条转向后的鱼rotated_sprite=pygame.transform.rotate(sprite,sprite_rotation)#获得转向后的矩形w,h=rotated_sprite.get_size()sprite_draw_pos=Vector2(sprite_pos.x-w/2,sprite_pos.y-h/2)screen.blit(rotated_sprite,sprite_draw_pos)time_passed = clock.tick()time_passed_seconds = time_passed / 1000.0# 图片的转向速度也需要和行进速度一样，通过时间来控制sprite_rotation += rotation_direction * sprite_rotation_speed * time_passed_seconds# 获得前进（x方向和y方向），这两个需要一点点三角的知识heading_x = sin(sprite_rotation * pi / 180.)heading_y = cos(sprite_rotation * pi / 180.)# 转换为单位速度向量heading = Vector2(heading_x, heading_y)# 转换为速度heading *= movement_directionsprite_pos += heading * sprite_speed * time_passed_secondspygame.display.update()