UDP Library Example

Contributed Library Questions

kchandr7

in Contributed Library Questions • 1 year ago

Is there sample code somewhere to receive UDP packets?

The UDP library I downloaded, does not seem to have any example programs.

Replies(8)

kchandr7

Re: UDP Library Example

1 year ago

I got Processing to receive the packets fine, but how do I get to draw them?

import hypermedia.net.*;
int PORT_RX=0XC350;
String HOST_IP = "192.168.1.100";//IP Address of the PC in which this App is running
UDP udp;//Create UDP object for recieving
void setup(){
udp= new UDP(this, PORT_RX, HOST_IP);
udp.log(true);
udp.listen(true);
noLoop();
}
void draw(){
}
void receive(byte[] data, String HOST_IP, int PORT_RX){
String value=new String(data);
println(value);
}

mataarsak

Re: UDP Library Example

1 year ago

how can we save receiving data into an array instead of string and then print them on the screen ? any body knows?

PhiLho

Re: UDP Library Example

1 year ago

How do you want to "draw" them? If that's just displaying the string, see the text() function.

kchandr7

Right, I meant displaying the string. I did notice something funny though when I choose a different font or even a larger size. It displays block characters in place of the null data. This does not occur when I leave the font at default.

Default Text

Different Font Type(same effect with changing font size using the textSize()) command.

PhiLho

Re: UDP Library Example

1 year ago

Perhaps use trim() to get rid of \n and such control chars.

kchandr7

Re: UDP Library Example

1 year ago

Thank you, that worked!

patmcc19

Re: UDP Library Example

6 months ago

Kchandr, could you post your code for the reading of the packets? I'm trying to do almost the same thing I think and would Iike to see how you did it.

Thanks.

kchandr7

Re: UDP Library Example

6 months ago

Hi,

Sure, let me know if you have any questions. It's been a while since I worked on this though.

//import ui library for buttons
import controlP5.*;
ControlP5 cp5;
//import udp library
import hypermedia.net.*;
UDP udpRX,udpTX;
//variables for udp
String ip="192.168.1.100";
int portRX=51000;
int portTX=50000;
int rx_buffer_size=100;
String rx_string="Waiting for Data";
byte[] rx_byte=new byte[rx_buffer_size];
int rx_byte_count=0;
//set strings for sending on udp
String s0="Zero";
String s1="One";
String s2="Two";
void setup(){
//set window dimensions
size(700,300);
//disables drawing outlines
noStroke();
//create new cp5 object for this user
cp5=new ControlP5(this);
//create 3 buttons
for (int i=0;i<3;i++){
cp5.addBang("Send"+i)
.setPosition(400+i*80,200)
.setSize(60,40)
.setColorForeground(140)
.setId(i)
;
}//end of for loop
//create new object for transmitting
udpTX=new UDP(this,portTX,ip);
udpTX.log(true);
udpTX.setBuffer(5);
udpTX.loopback(true);
//create new object for receiving
udpRX=new UDP(this,portRX,ip);
udpRX.log(true);
udpRX.listen(true);
//confirm if tx is multicast and loopback is disabled
println("Is TX mulitcast: "+udpTX.isMulticast());
println("Has TX joined multicast: "+udpTX.isJoined());
println("Is loopback enabled on TX: "+udpTX.isLoopback());
//confirm if rx is multicast
println("Is RX mulitcast: "+udpRX.isMulticast());
println("Has RX joined multicast: "+udpRX.isJoined());
//stop looping setup
noLoop();
}//end of setup()
void draw(){
//set background color, also clears the screen
background(0);
//misc
int off_x=200;
//main title
fill(255);
textSize(25);
text("UDP Tool",20,30);
fill(200);
//IP address
textSize(20);
text("IP Address:",20,30+25);
fill(252,10,55);
text(ip,130,30+25);
fill(200);
//UDP ports
text("Port(Sending):",20,30+25+20);
fill(252,10,55);
text(portRX,155,30+25+20);
fill(200);
text("Port(Receiving):",20,30+25+40);
fill(252,10,55);
text(portTX,170,30+25+40);
fill(200);
text("Last Packet Received:",20,30+25+120);
fill(252,10,55);
text(rx_string,230,30+25+120);
fill(200);
text("Total Bytes Recieved:",20,30+25+140);
fill(252,10,55);
text(rx_byte_count,230,30+25+140);
//start looping draw
loop();
}//end of draw()
//event handling
public void controlEvent(ControlEvent theEvent) {
if(theEvent.getController().getId()==0){
println("String Sent: "+s0);
udpTX.send(s0,ip,portTX);
}
if(theEvent.getController().getId()==1){
println("String Sent: "+s1);
udpTX.send(s1,ip,portTX);
}
if(theEvent.getController().getId()==2){
println("String Sent: "+s2);
udpTX.send(s2,ip,portTX);
}
}//end of event
//udp receive handling
void receive(byte[] data, String ip, int portRX){
String value=new String(data);
println(value);
rx_byte_count+=data.length;
//clear receive byte array
for(int j=0;j<rx_byte.length;j++)
{
rx_byte[j]=0;
}
//copy received bytes to rx_byte array
arrayCopy(data,rx_byte);
//copy bytes to a string and trim string to remove nulls
rx_string=new String(rx_byte);
rx_string=trim(rx_string);
//is called to update the received string
redraw();
}

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