Use AYON event system for 3dsMax Callback

Is there an existing issue for this?

[X] I have searched the existing issues

Current Behavior:

Why isn't 3dsmax using the OpenPype event system like the other hosts? Let's create an issue to track that and fix that in a separate PR. Each host should try and emit the events in a DCC agnostic way so that global OpenPype tooling could hook into it, like scene saves, etc.

_Originally posted by @BigRoy in https://github.com/ynput/OpenPype/pull/5499#discussion_r1315901738_

Expected Behavior:

Using AYON event system for the callbacks in 3dsmax.
Can take references from the Maya hosts.

Version

3.16.5

What platform you are running AYON on?

Windows

Steps To Reproduce:

n/a

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Relevant log output:

No response

Additional context:

No response

[cuID:OP-6769]

For more details on Max's event system see these documentation pages:

As such it looks like that on host install we should be able to do this in OpenPype:

pseudocode

from functools import partial
from openpype.lib import (
    register_event_callback,
    emit_event
)

import pymxs
rt = pymxs.runtime

def emit_event_notification_param(event):
    notification = rt.callbacks.notificationParam()
    emit_event(event, {"notificationParam": notification})

def register_callbacks():

    id = rt.Name("openpype_callbacks")

    # init
    rt.callbacks.addScript(
        rt.Name('postSystemStartup'),
        partial(emit_event_notification_param, "init"),
        id=id
    )

    # open
    # todo: we might want filePreOpenProcess and filePostOpenProcess?
    rt.callbacks.addScript(
        rt.Name('filePreOpen'),
        partial(emit_event_notification_param, "before.open"),
        id=id
    )
    rt.callbacks.addScript(
        rt.Name('filePostOpen'),
        partial(emit_event_notification_param, "open"),
        id=id
    )

    # save
    # todo: we might want filePreSaveProcess and filePostSaveProcess?
    rt.callbacks.addScript(
        rt.Name('filePreSave'),
        partial(emit_event_notification_param, "save"),
        id=id
    )
    rt.callbacks.addScript(
        rt.Name('filePostSave'),
        partial(emit_event_notification_param, "after.save"),
        id=id
    )

    # new
    # todo: not entirely sure whether systemPostNew means "new file"
    rt.callbacks.addScript(
        rt.Name('systemPostNew'),
        partial(emit_event_notification_param, "new"),
        id=id
    )

Then that would roughly mimic what Maya does by emitting OpenPype events:

"init" dcc startup initialization finished
"save" workfile saved
"open" workfile opened
"new" new workfile started

Which is implemented in Maya here and then install also install callbacks to those here.

Removing all callbacks should then be as easy as:

rt.callbacks.removeScripts(id=rt.name("openpype_callbacks"))

I have never worked in 3DsMax so take this with a grain of salt.

ynput / ayon-3dsmax