How to send data from python to my c++ plugin?

Helper

On 17/07/2018 at 06:48, xxxxxxxx wrote:

Hi everyone.

Not sure if this is the right branch of forum, but I think that problem is in my python code..

I'm trying to learn C4D CPP API and I've stucked. I can't figure out how to read the data that i sent from python node to my c++ TagData plugin with Message().

My plugin code(part of it) :

MyTestPlugin.cpp   
class MyTestPlugin:TagData{  
...  
...  
Bool MyTestPlugin::Message(GeListNode *node, Int32 type, void *data)  
{  
  if (type == 322)  
  {  
      GePrint("___Event Fired___");  
      if (!data)  
          return false;  
      GePrint(String::IntToString( (Int32)data ));  
      GePrint(String::IntToString( *(Int32* )data ));  
  }  
  return true;  
}  
...  
...

And my python code(XPresso node) looks like:

import c4d
  
def main() :  
  _myCustomTag.Message(322, 112233)

The output:
___Event Fired___
415747088
15

If I'm not mistaken the problem is that python sends message with < Int32> data inside and cpp waits for < Int32*>. But I just can't figure out what to do.(((
Please help.

Helper

On 18/07/2018 at 06:42, xxxxxxxx wrote:

Hi dmitry82,

Actually, the problem is that you are sending a python object to a C++.
So the best way to do it is to use a BaseContainer to send your data, and use MSG_BASECONTAINER.

So your C++ code will looks like

if (type == MSG_BASECONTAINER)
{
	GePrint("___Event Fired___");
	if (!data)
		return false;
	BaseContainer* bc = (BaseContainer* )data;
	if (bc == nullptr)
		return false;
  
	Int32 value = bc->GetInt32(0, 10);
}

and your python code

bc = c4d.BaseContainer()
bc[0] = 100
_myCustomTag.Message(c4d.MSG_BASECONTAINER, bc)

Please note Message function is executed immediately when you call it, that means you get the same limitation as you get in a threaded context (Xpresso Node), which is to not change the scene structure within this call, for more information please read the C++ Manual about threading.

If you have any question, please let me know,
Cheers,
Maxime

Helper

On 04/08/2018 at 03:54, xxxxxxxx wrote:

Sorry for late reply.
Thanks for your answer - it helped me a lot.

Actually, it's strange that you have to use BaseContainer wrap for every piece of primitive data. I think sometimes it must be seriously hurting perfomance.
Anyway, thanks again, Maxime. Best wishes.