在pygame中来回移动精灵

Question

I have the sprite going from on end of the screen to the other, but now I want it to go back and forth forever. Any ideas?

u = 1 #u is the x coordinate
if u < 430: #480 is the window siz, i want it to stop at 430
   u += 5 # Move up by 5

Should I add my whole code so it is easier?

Answer 1

You can use a delta variable:

delta = 5
u = 1

and have it adjusted to switch directions:

u += delta
if u >= 430: 
   delta = -5
elif u < 50:
   delta = 5