Create a video using processing opengl

Issue

I am creating a REST API to generate video dynamically based on user input and provided animation types. So, I am using processing 2.2.1 for this. I want to generate 3D animation using OPENGL. But OPENGL requires Window object. Since I am using processing in background to just generate frame, how can I use processing with OPENGL to generate animated frames without interactive means without displaying the window.

My sample code

import com.hamoid.VideoExport;
import processing.core.*;

public class CircleSketch extends PApplet {

    private VideoExport videoExport;

  public void setup() {
    size(400, 400,OPENGL);
    videoExport = new VideoExport(this, "F:/work/tmp.mp4");
    background(0);
  }
  public void draw() {
    background(0);
    fill(200);
    rotateX(radians(50));
    rectMode(CENTER);
    rect(width/2,height/2, 100, 100);
    videoExport.saveFrame();
  }
}

DisplayFrame Class

public class DisplayFrame extends javax.swing.JFrame {
    public DisplayFrame(){
        this.setSize(600, 600); //The window Dimensions
        setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);
        javax.swing.JPanel panel = new javax.swing.JPanel();
        panel.setBounds(20, 20, 600, 600);
        processing.core.PApplet sketch = new CircleSketch();
        panel.add(sketch);
        this.add(panel);
        this.setVisible(false);
        //this is the function used to start the execution of the sketch
        sketch.init();     
    }
    
    
    
    public static void main(String[] args) {
       new DisplayFrame().setVisible(false);
    }    
}

Any suggestion please???

Solution

how can I use processing with OPENGL to generate animated frames without interactive means without displaying the window.

In short terms: Given the current OpenGL driver models you can't (as long as you want to use a GPU for rendering). Period, that's how it is.

If you can live with software rendering (slow), then there's OSMesa. Also in the forseeable future there should be changes in the driver models, which allow to use OpenGL in a headless environment. Until then, you need a window of some sort on a graphics environment that actually actively feeds a display output (so it doesn't suffice to start a X11 server and background it).

Answered By - datenwolf