Coda Project for GravField

Considering the real-time data processing requirements for GravField's live performances，we choose Coda.js as live-coding environment.

We added OSC communication capabilities to Coda, enabling it to receive data signals from Unity Server and send control signals back to Unity Server.

System Requirement:

Nodejs Version: v16.20

System Machanism:

As coda runs in web environment, it can't receive UDP messages directly. You have to start a UDP server as a message transfer station, then the UDP server will communicate with coda via websocket.

Installation

• Install codajs platform by running command in CodaProject folder
  

npm install

• Install UDP server by running command in sub-folder called "playground"
  

cd playground
npm install

Run Order

• Start UDP server by running command in CodaProject folder
  

npm run socket

• Start Coda by running command in CodaProject folder
  

npm run dev

IP Configuration

To change the ip port that UDP server connects with, open /playground/server.js and modify ip and port in it.

Listening

const osc = require('osc');
const udpPort = new osc.UDPPort({
  localAddress: '0.0.0.0', //listen from all possible ip address
  localPort: 13500, //change port here
  metadata: true,
});

Sending

const unityOscIp = "127.0.0.1";
const unityOscPort = 13600;

Avaliable Functions

• performer(id) to get performer position.
• oscto(id, address) to send command to specific performer.
• osctoall(address) to send command to all performers.
• pfm_maxy(ids) to calculate max of Y position among specific performers.
• pfm_miny(ids) to calculate min of Y position among specific performers.
• pfm_dist(ids) to calculate distance between specific performers.

Avaliable Address

Sending data to osc adress is setting a parameter in Unity application. Current available address includes

OSC Address	Need Specify ID	Rough Range	Type	Description
mode	No	0, 1, 2	int	Change effect mode
rope-mass	Yes	[20, 80]	float	How heavy the rope is.
rope-maxwidth	Yes [1, 40]	float	Max thickness of the central part of the rope
rope-scaler	Yes [1, 10]	float	Make it easier to swing the rope
rope-offset	Yes [-10,10]	float	Vertical offset to head
spring-freq	Yes	[0, 200]	float	Sine frequency
spring-width	Yes	[0.2, 400]	float	Max width
mag	Yes	0,1	int	Is positve
magrandom	No	0,1	int	Randomize magnetic for all

Coda will add / automatically to complete osc address for you.

Usage Example

const sm = periodic(1000)
// change to mode 0
.constant(0)
.osctoall("mode");

const sm = periodic(10)
// show position of performer A
.performer("A")
.plot()
// calculate distance between A and C
.pfm_dist("AC")
.plot()
// set thickness react with distance
.scale({ outmin: 0, outmax: 10 })
.oscto("AC", "thickness");