EventCallbackProblem

[renderfan]

Hello all!

I have Python Sop and inside node I have function to split some polygons. But because splitting takes long time I want to do it only if geometry of input does change. I tried to use hou.Node.addEventCallback but it does not work for me. What I have so far is code below:

event_types = (hou.nodeEventType.InputDataChanged, hou.nodeEventType.InputRewired)
def split_polygons(geo):
"do some splitting"
return polygons
def onchange(**kwargs):
node_in = kwargs["node"]
geo_in = node_in.geometry()
split_polygons(geo_in)

node.addEventCallback(event_types, onchange)
polygons = split_polygons(geo)
"do something with polygons"
[/CODE]

This does not work because I do not know how I can get the polygons which are returned by function only if input change.

Thank you in advance!!!