VPython and threads?

[Bartłomiej Stodulski]

Hello, can anyone tell me if there is a way to run threads with Visual Python? Or is there any other solution ? I'm making project that needs to run for example two 3D objects from VP that move in other directions at the same time and do a lot of other stuff separately.

Cheers,

B.S.

[Steve Spicklemire]

Threads are used internally so I don't see any reason why they couldn't be used. Have you encountered a particular problem? Can you post an example the fails?

thanks,

-steve

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[Bartłomiej Stodulski]

from visual import *

def create_and_move(w):

    ball = sphere(pos=(0,0,0))

    ball.velocity = vector(0,0,w)

   

    while True:

        rate(100)

        ball.pos = ball.pos + ball.velocity*0.01

try:

    thread.start_new_thread(create_and_move,-1)

    thread.start_new_thread(create_and_move,1)

except:

    print('Thread Error')

while 1:

    pass

It doesn't work. I just want to create a somekind of a function that creates objects, sets their vectors and changes their position at the same time.

[Bruce Sherwood]

I think that it is not possible to have two threads that contain rate() statements, because only the main thread can process window events, and there's some kind of collision with wxPython, upon which VPython is based. Here however is a scheme that my do what you want, in that you can have multiple objects animated, and a separate process p can be running along in a separate thread.

from __future__ import division, print_function

import thread

import time

from visual import *

scene.range = 10

def create(w):

    b = sphere(pos=(0,0,0), radius=0.5)

    b.velocity = vector(w,0,0)

    return b

balls = [create(1), create(-1)]

def p(a):

    while True:

        time.sleep(0.2*a)

        if a == 1:

            balls[0].color = color.cyan

            balls[1].color = color.red

        else:

            balls[0].color = color.magenta

            balls[1].color = color.yellow

try:

   thread.start_new_thread( p, (1,) )

   thread.start_new_thread( p, (2,) )

except:

   print("Error: unable to start thread")

while True:

    rate(100)

    for ball in balls:

[Bartłomiej Stodulski]

Thank You very much Sir, really appreciate Your help!

Best regards, from Polish student

B.S.