All, Apologies in advance: I'm new to Python and OO, and I'm sure this is a really simple question, but I just can't seem to crack it on my own, or through looking at examples. I'm playing around with VPython (http://www.vypthon.org) to try and teach myself about objects: I've got a box that I've put some balls in, and I'm trying to get said balls to move around and bounce off the walls of the box -- that's literally it. I can put multiple balls in the box, but I can't get them to update their position -- it works when I have one ball, but now that I have a list of balls, I can't get them to move.
I've copied in the code I'm using below, as it's not very long -- can anyone help me? <--START--> from visual import * from random import randrange # to create random numbers numballs = 5 # number of balls balls = [] # a list to contain the balls # set up a box to collide with side_length = 100 minx = side_length * -10 maxx = side_length * 10 miny = side_length * -4 maxy = side_length * 4 # create a wireframe of space left = curve(pos=[(minx, miny),(minx, maxy)], color = color.white) top = curve(pos = [(minx, maxy),(maxx, maxy)], color = color.white) right = curve(pos = [(maxx, maxy),(maxx, miny)], color = color.white) bottom = curve(pos = [(maxx, miny),(minx,miny)], color = color.white) #create some balls for b in range(numballs): # for each ball x = randrange(minx, maxx) y = randrange(miny, maxy) balls.append(sphere(pos = (x,y), radius = 50, color = color.red)) # add balls dt = 0.05 # time interval velocity = vector(2,0.2,1) # velocity of the balls while (1==1): # forever ... rate(50) for b in range(numballs): # for each ball ... if balls[b].x < minx: # check it hasn't overrun a boundary balls[b].x = maxx if balls[b].x > maxx: balls[b].minx if balls[b].y < miny: balls[b].y = maxy if balls[b].y > maxy: balls[b].y = miny # NB betting this is where it's going wrong ... balls[b].pos = balls[b].pos + (velocity * dt) # update the position of the ball <--END--> Any ideas? I've run out of options. Any help would be very *gratefully* appreciatedd!! Thanks in advance JW -- http://mail.python.org/mailman/listinfo/python-list