Pyglet：on_draw中的变量

Question

My code uses on_draw() to display some figures, it uses global variables as the parameters of those figures.

I would like to know how to send local variables from the main() function to on_draw() . Is it possible?

Answer 1

I'm not familiar with Pyglet, but I'll try and answer.

If you want to use global variables from main() , declare the variables from within the on_draw() with the global keyword.

For example in the global space (outside of any functions).

x = 5

In your on_draw() :

global x
#whenever you refer to x from now on, you will be referring to the x from main
#do something with x
x = 10

Now if you're in your main() again:

global x
print(x)

> 10

Answer 2

To add to Lee Thomas's answer, here is a complete snippet that can actually perform actions based on the value of the variable anywhere in the code:

import  pyglet

x = 0 #declaring a global variable

window = pyglet.window.Window()#fullscreen=True
one_image = pyglet.image.load("one.png") 
two_image = pyglet.image.load("two.png") 
x = 10 #assigning the variable with a different value 
one = pyglet.sprite.Sprite(one_image)
two = pyglet.sprite.Sprite(two_image)
print "x in main, ", x


@window.event
def on_draw():
    global x #making the compiler understand that the x is a global one and not local
    one.x = 0
    one.y = 0
    one.draw()
    two.x = 365
    two.y = 305
    two.draw()
    print "x in on_draw, ", x

pyglet.app.run()    

Once I run the code, I get the output

Hope this helps