import processing.core.*;
                     


                     
public class Driver extends PApplet
                     
{
                     
 public void setup() {
                     
 size(200,200);
                     
 background(0);
                     
 }
                     


                     
 public void draw() {
                     
 stroke(255);
                     
 if (mousePressed)
                     
 line(mouseX, mouseY, pmouseX, pmouseY);
                     
 }
                     
}
                    

* Create a new folder named "lib" in project root.

* Right click lib folder, import. general, filesystem. Browse to your processing folder ".../processing-0199/lib"

* Select core.jar and finish

* Right click core.jar, build path->add to build path.

At this point the project will run fine.

Next, OpenGL functionality is added.

* Right click lib folder, import. general, filesystem. ".../processing-0199/modes/java/libraries/opengl/library"

* Select all the .jar files: gluegen-rt.jar, jogl.all.jar, nativewindow.all.jar, and opengl.jar.

* Right click each of the .jar files and select build path->add to build path.

* Create a new folder named "natives" in lib folder.

* Right click "natives", import. general, filesystem. ".../processing-0199/modes/java/libraries/opengl/library/windows32"

* Select all the .dll files and import them.

      gluegen-rt.dll

      jogl_desktop.dll

      jogl_es1.dll

      jogl_es2.dll

      nativewindow_awt.dll

      nativewindow_win32.dll

      newt.dll

* Go to the Project menu->Properties. Java Build Path. Libraries tab. For each of gluegen-rt.jar, jogl.all.jar, nativewindow.all.jar, and opengl.jar:

      click Native library location and Edit...

      select Workspace...

      select lib/natives

* In Driver.java,

      add "import processing.opengl.*;" below "import processing.core.*;"

      change size(200, 200); to size(200, 200, OPENGL);

If you don't clear and redraw the entire screen each frame you may get flickering.

Here is the example above with OpenGL enabled and redrawing everything each frame:

                    

                     
import processing.core.*;
                     
import processing.opengl.*;
                     


                     
import java.util.Vector;
                     


                     


                     
public class Driver extends PApplet
                     
{
                     
 public class Line
                     
 {
                     
 public float a,b,c,d;
                     
 
                     
 public Line(float inita, float initb, float initc, float initd) {
                     
 a = inita;
                     
 b = initb;
                     
 c = initc;
                     
 d = initd;
                     
 }
                     
 }
                     
 
                     
 Vector<Line> lineList = new Vector<Line>();
                     


                     
 public void setup() {
                     
 size(200,200,OPENGL);
                     
 }
                     


                     
 public void draw() {
                     
 background(0xFF000000);
                     


                     
 stroke(255);
                     
 if (mousePressed)
                     
 lineList.add(new Line(mouseX, mouseY, pmouseX, pmouseY));
                     
 
                     
 for(Line l : lineList)
                     
 line(l.a, l.b, l.c, l.d);
                     
 }
                     
}