UDP

Replies to This Discussion

Permalink Reply by Luis Fraguada on August 20, 2009 at 12:34pm

It will freeze no matter what refreshes the canvas. Check out the new timer component...does something similar to Giulio's "the engine." the idea is to do it asynchronously, having one thread waiting for the info. I've been too busy to jump on that at the moment, and actually, though some components (image) work asynch, I am not sure GH script nodes allow it... Perhaps David or Rajaa could answer that.

By the way, is your data feed continuous?

Permalink Reply by Olivier Pasquet on August 22, 2009 at 8:09am

Thanks for your answer!
One of the problem is Giulio's "the engine" does not work with me. I could not figure out why. I guess this is not a version problem since I have the latest ones.

It seems that you cannot use multithreading with VB because you cannot add imports. So impossible to add "Imports System.Threading". I'm not sure it would work anyway.

Permalink Reply by Olivier Pasquet on August 22, 2009 at 8:11am

Here is my super simple code. In case someone seems something wrong.

If onoff Then
Dim rUDPClient As New System.Net.Sockets.UdpClient
rUDPClient = New System.Net.Sockets.UdpClient(11000)
Dim receiveBytes As [Byte]()
Dim RemoteIpEndPoint As System.Net.IPEndPoint = New System.Net.IPEndPoint(System.Net.IPAddress.Any, 1111)

receiveBytes = rUDPClient.Receive(RemoteIpEndPoint)
A = System.Text.Encoding.ASCII.GetString(receiveBytes)
End If

(I know this should go to the VB.net discussion threads but I started to talk about this here.)

Thanks again.

Permalink Reply by Olivier Pasquet on August 22, 2009 at 9:41am

Oops. I had not seen the Giulio Piacentino's patches. It works perfectly!! Many thanks !
You saved me a lot of time...

Permalink Reply by Giulio Piacentino on August 21, 2009 at 11:38am

Hi Oliver, this simple UDP asynchronous listener should help you in this task. It is tested only with Processing (sorry, I don't have Max). It listens to the loopback address, but you can change this. In this case it does not freeze the sketch - it simply drops frames or re-releases old ones if the connection is too slow. It could be re-worked to be used in other scenarios, though.

It uses with the Timer from Grasshopper version GH 0.6.19. I am sending the Processing sketch as well, so you can test it (with Processing version 1.0.5 and Stephane Cousot's UDP library udp.zip from http://processing.org/reference/libraries/ ).

One small remark: this is a listener on the very basic UDP layer. You need to define the way you want your data to be subdivided (which bytes, small or big endian, strings, etc you want to use).
I hope this helps and please let me know more details if you need any further help.

Attachments:

• UDP.ghx, 48 KB
• UPD.pde, 2 KB

Permalink Reply by Luis Fraguada on August 21, 2009 at 12:34pm

"Perhaps David or Rajaa could answer that."

Or Giulio...coooool! Nicely done.

Permalink Reply by Bob Frederick on August 21, 2009 at 6:02pm

Wow. Thank you.

Permalink Reply by Olivier Pasquet on August 22, 2009 at 10:22am

Hi Giulio, It works perfectly!! Many thanks ! You saved me a lot of time... Really nice from you for sharing this stuff.
Here is a simple and obvious Max patch to send data to Grasshooper using udp.
Only "mxj net.udp.send" sends proper lists to Grasshooper. "udpsend" does not (small format problem).

Attachments:

• send-udp-to-grass.maxpat, 11 KB

Permalink Reply by Giulio Piacentino on August 22, 2009 at 10:43am

Hi Oliver, nice to hear this.

If you want to receive things other than ASCII strings, you could try using methods of the System.BitConverter and System.Convert classes (ToByte, ToDouble, etc.. from Byte[]) instead of System.Text.Encoding.ASCII. Differences in "endianess" can be dealt with System.Net.IPAddress.NetworkToHostOrder(). BitConverter.IsLittleEndian tells what "endinaness" your system has. I never had trouble with this, though, as I used the same tipe of machines on both receiver and sender sides.

Permalink Reply by Olivier Pasquet on August 23, 2009 at 8:05am

Thank you for the info. Indeed, this works fine. Max also has an object that works fine "mxj net.udp.send" with no need of changing your code.
I'm now trying to convert the incoming string as a list of ints for point coordinates. I'll try to figure out how today. ;)

Permalink Reply by Miguel Vidal on August 27, 2009 at 6:34am

Hi everyone, thanks a lot for the posts and the code! It´s awesome!

I attach Giulio´s script with the Split routine added in order to have several types of data, numerical and textual, streaming at the same time.

In the script the implemented protocol is like:

"data_1::data_2:: ... ::data_N"

So, in your server application you can create the stream using a routine like this :
(using Java sintax)

// the message to send with the first datum
String message = String.valueOf( datum_0 );

// new data added with the separator "::"
message += "::";
message += String.valueOf(datum_1 );

// ... the same until the last one
message += "::";
message += String.valueOf(datum_N );

// Then stream data
udp.send( message, ip, port );

Note we use the String.valueOf() method in order to convert different numeric types to strings and concatenate them to the message string.

I have tried it with processing as you can see in the video. Hope it is useful.

Cheers!

Attachments:

• basic_udp_server.pde, 1 KB
• UDP_in.ghx, 177 KB

Permalink Reply by Giulio Piacentino on September 1, 2009 at 5:53am

Nice to see it being used! If you want to try a loopback into Processing, see the new UDP receiver+sender here (example with Processing as usual).

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