Question

一个简单的问题：为什么第一个代码工作，但看起来相同的第二个代码在pygame窗口出现时会冻结？

# Moving Pan
# Demonstrates mouse input

from livewires import games

games.init(screen_width = 640, screen_height = 480, fps = 50)

class Pan(games.Sprite):
    """ A pan controlled by the mouse. """
    def update(self):
        """ Move to mouse coordinates. """
        self.x = games.mouse.x
        self.y = games.mouse.y

def main():
    wall_image = games.load_image("wall.jpg", transparent = False)
    games.screen.background = wall_image

    pan_image = games.load_image("pan.bmp")
    the_pan = Pan(image = pan_image,
                  x = games.mouse.x,
                  y = games.mouse.y)
    games.screen.add(the_pan)

    games.mouse.is_visible = False

    games.screen.event_grab = True

    games.screen.mainloop()

# kick it off!
main()

故障的第二个：

from livewires import games,color
games.init (screen_width = 640, screen_height = 480, fps = 50)

#Creating a moving object tied to the cursor. This includes one method with two
#lines of code.
class Pan (games.Sprite):
    def moved (self):
    #Receives mouse position
        self.x = games.mouse.x
    #Changes mouse position to new x,y values.
        self.y = games.mouse.y

#The Main
myscr = games.screen
myscr.set_background (games.load_image ("wall.jpg", transparent = False))
pan_image = games.load_image ("pan.bmp")
le_pan = Pan (image = pan_image,
              x = games.mouse.x,
              y = games.mouse.y)

games.mouse.is_visible = False
myscr.add (le_pan)
myscr.event_grab = True
myscr.mainloop()

Answer 1

我从未使用过livewires，但在游戏中你通常需要 - 或多或少 - 无尽的游戏循环。

游戏循环背后的意义是，你总是想知道鼠标在哪里或按下了什么键，而不仅仅是一次！所以你必须一遍又一遍地问Where is the mouse?。为实现这一目标，您可以使用循环来检查每次执行时所需的所有内容。

在第一个例子中，游戏循环是函数main。应用程序的流程如下：

导入所需的库
```
from livewires import games
```

初始化游戏画面

games.init(screen_width = 640, screen_height = 480, fps = 50)

声明可以在屏幕上显示的精灵

class Pan(games.Sprite):
    """ A pan controlled by the mouse. """
    def update(self):
        """ Move to mouse coordinates. """
        self.x = games.mouse.x
        self.y = games.mouse.y

声明主要方法并设置游戏屏幕背景

def main():
    wall_image = games.load_image("wall.jpg", transparent = False)
    games.screen.background = wall_image

将上面定义的精灵添加到屏幕并将其移动到鼠标光标的位置

    pan_image = games.load_image("pan.bmp")
    the_pan = Pan(image = pan_image,
                  x = games.mouse.x,
                  y = games.mouse.y)
    games.screen.add(the_pan)

使鼠标光标不可见并激活事件

    games.mouse.is_visible = False
    games.screen.event_grab = True

运行mainloop 。此方法的调用显示：Run me ( function main ) over and over!
```
    games.screen.mainloop()
```
第一次致电
```
main()
```

在第二个例子中，没有游戏循环。应用程序的流程（更紧凑）是这样的：

导入库，初始化游戏画面，声明精灵

from livewires import games,color
games.init (screen_width = 640, screen_height = 480, fps = 50)

class Pan (games.Sprite):
    def moved (self):
        self.x = games.mouse.x
        self.y = games.mouse.y

设置游戏画面背景并添加精灵

myscr = games.screen
myscr.set_background (games.load_image ("wall.jpg", transparent = False))
pan_image = games.load_image ("pan.bmp")
le_pan = Pan (image = pan_image,
              x = games.mouse.x,
              y = games.mouse.y)
myscr.add(le_pan)

停用鼠标光标，启用事件

games.mouse.is_visible = False
myscr.event_grab = True

运行mainloop 。此方法的调用显示：Run me ( function undefined ) over and over!
```
myscr.mainloop()
```

这是关键点！ 您无法调用Python文件根目录中的代码！ mainloop函数不知道返回的位置或从哪里开始。电话会丢失，你的程序会冻结。游戏画面无法更新，因为没有任何东西告诉它应该如何更新。

结论：你必须拥有游戏循环的功能！

调试示例Pygame代码？

1 个答案: