building a parameter menu as a background process

[jonp]

Greetings,

I have a scripted menu parameter that is built from a filtered, sometimes extremely long list of files.  When I select a node with this parameter, the first time I do it there is a very long pause where I cannot do anything in the UI.  Subsequent access is faster as I'm caching the results of the first lookup.  HOWEVER, the first pause is annoying enough.  It would be great if there was a way to build the menu contents as a background process somehow and just have the menu script read from a stored list somewhere that is continuously updated (with a caveat message in the menu saying that the list is still being built).

Any ideas on how to elegantly do this?

 

Cheers,

Jon

[f1480187]

Try threading:

import threading

node = kwargs['node']

if not node.cachedUserData('menu'):
    menu = ['', 'Loading items...\nReturn in 10 seconds...']
    node.setCachedUserData('menu', menu)

    def fetch_menu():
        # Simulate long operation.
        import time
        time.sleep(10)
        menu = ['item1', 'Label 1', 'item2', 'Label 2']

        try:
            node.setCachedUserData('menu', menu)
        except hou.ObjectWasDeleted:
            pass

    t = threading.Thread(target=fetch_menu)
    t.start()

return node.cachedUserData('menu')

To reset, just delete node and undo.

To update menu items automatically, add this under try statement:

parm = kwargs['parm']
group = node.parmTemplateGroup()
template = parm.parmTemplate()
template.setMenuItems(menu[0::2])
template.setMenuLabels(menu[1::2])
group.replace(parm.name(), template)
node.setParmTemplateGroup(group)

slow_menu.hipnc

[jonp]

Great tip, thanks!  I didn't know if Houdini would lock up anyways using threading.  Fortunately it does not!

Edited January 22, 2017 by jonp