gl4java-usergroup

[gl4java-usergroup] Newbie: Using GLJPanel

[Chad S. <sta...@ea...>]

Hello, I'm attempting to learn OpenGL by following the NeHe tutorials, =
and using the GLJPanel to do so.  However, I have so far been unable to =
get anything to display.  The frame is being displayed, but nothing is =
being painted.  I get no error message until I resize or close the =
window, at which point I'm notified that gljDestroy failed (free).

Any help would be appreciated.

Thanks, Chad

Below is the code I'm running:
---------------------------------------------------------------------

import gl4java.swing.GLJPanel;
import java.awt.BorderLayout;
import javax.swing.JFrame;

public class Exercise2
extends GLJPanel
{

 // Constructors

 public Exercise2()
 {
  super(false);
 }

 // Overridden GLJPanel Protocol

 public void
 init()
 {
  super.init();
  gl.glClearColor(0.0f, 0.0f, 0.0f, 0.0f);
  gl.glClearDepth(1.0f);
  gl.glShadeModel(GL_SMOOTH);
  gl.glEnable(GL_DEPTH_TEST);
  gl.glDepthFunc(GL_LESS);
  gl.glHint(GL_PERSPECTIVE_CORRECTION_HINT, GL_NICEST);
 }

 public void
 display()
 {
  if (!glj.gljMakeCurrent())
  {
   System.out.println("Make current failed");
   return;
  }

  System.out.println("Started rendering");

  gl.glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
  gl.glLoadIdentity();

  gl.glColor3f(1.0f, 1.0f, 1.0f);
  gl.glTranslatef(-1.5f, 0.0f, -6.0f);
  gl.glBegin(GL_TRIANGLES);
   gl.glVertex3f(0.0f, 1.0f, 0.0f);
   gl.glVertex3f(-1.0f, -1.0f, 0.0f);
   gl.glVertex3f(1.0f, -1.0f, 0.0f);
  gl.glEnd();

  System.out.println("Ended rendering");

  glj.gljSwap();
  glj.gljFree();
 }

 public void
 reshape(int pWidth, int pHeight)
 {
  gl.glViewport(0, 0, pWidth, pHeight);
  gl.glMatrixMode(GL_PROJECTION);
  gl.glLoadIdentity();
  glu.gluPerspective(45.0f, (float)pWidth/(float)pHeight, 0.1f, 100.0f);
  gl.glMatrixMode(GL_MODELVIEW);
 }

 // Test Driver

 public static void
 main(String[] args)
 {
  JFrame lFrame =3D new JFrame("Exercise2");
  Exercise2 lPanel =3D new Exercise2();

  lFrame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
  lFrame.getContentPane().add(lPanel, BorderLayout.CENTER);
  lFrame.setSize(300, 300);
  lFrame.show();
 }

}

Re: [gl4java-usergroup] Newbie: Using GLJPanel

[Chad S. <sta...@ea...>]

Problem resolved - Only after turning on the GLContext debugging (whose =
debugging capabilities should be much more prominently documented) was I =
able to determine that an exception was being thrown at the end of my =
display method.  It turns out that the glSwap call was the problem.  If =
I remove it and instead wrapper the display methods in a pushMatrix(), =
popMatrix() combo, everything works fine.

Now my question is: Why doesn't glSwap work even after I changed the =
constructor to specify doubleBuffer =3D true?  Does anyone know the =
rules?  I notice that the converted NeHe tutorials use glSwap, but are =
run within the context of an Applet.  None of the Swing demos use =
glSwap.  Is its usage verboten in Swing?

Thanks in Advance, Chad
  ----- Original Message -----=20
  From: Chad Stansbury=20
  To: gl4...@li...=20
  Sent: Friday, June 07, 2002 6:13 PM
  Subject: [gl4java-usergroup] Newbie: Using GLJPanel


  Hello, I'm attempting to learn OpenGL by following the NeHe tutorials, =
and using the GLJPanel to do so.  However, I have so far been unable to =
get anything to display.  The frame is being displayed, but nothing is =
being painted.  I get no error message until I resize or close the =
window, at which point I'm notified that gljDestroy failed (free).

  Any help would be appreciated.

  Thanks, Chad

  Below is the code I'm running:
  ---------------------------------------------------------------------

  import gl4java.swing.GLJPanel;
  import java.awt.BorderLayout;
  import javax.swing.JFrame;

  public class Exercise2
  extends GLJPanel
  {

   // Constructors

   public Exercise2()
   {
    super(true);
   }

   // Overridden GLJPanel Protocol

   public void
   init()
   {
    super.init();
    gl.glClearColor(0.0f, 0.0f, 0.0f, 0.0f);
    gl.glClearDepth(1.0f);
    gl.glShadeModel(GL_SMOOTH);
    gl.glEnable(GL_DEPTH_TEST);
    gl.glDepthFunc(GL_LESS);
    gl.glHint(GL_PERSPECTIVE_CORRECTION_HINT, GL_NICEST);
   }

   public void
   display()
   {
    if (!glj.gljMakeCurrent())
    {
     System.out.println("Make current failed");
     return;
    }

    System.out.println("Started rendering");

    gl.glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
    gl.glLoadIdentity();

    gl.glColor3f(1.0f, 1.0f, 1.0f);
    gl.glTranslatef(-1.5f, 0.0f, -6.0f);
    gl.glBegin(GL_TRIANGLES);
     gl.glVertex3f(0.0f, 1.0f, 0.0f);
     gl.glVertex3f(-1.0f, -1.0f, 0.0f);
     gl.glVertex3f(1.0f, -1.0f, 0.0f);
    gl.glEnd();

    System.out.println("Ended rendering");

    glj.gljSwap();
    glj.gljFree();
   }

   public void
   reshape(int pWidth, int pHeight)
   {
    gl.glViewport(0, 0, pWidth, pHeight);
    gl.glMatrixMode(GL_PROJECTION);
    gl.glLoadIdentity();
    glu.gluPerspective(45.0f, (float)pWidth/(float)pHeight, 0.1f, =
100.0f);
    gl.glMatrixMode(GL_MODELVIEW);
   }

   // Test Driver

   public static void
   main(String[] args)
   {
    JFrame lFrame =3D new JFrame("Exercise2");
    Exercise2 lPanel =3D new Exercise2();

    lFrame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    lFrame.getContentPane().add(lPanel, BorderLayout.CENTER);
    lFrame.setSize(300, 300);
    lFrame.show();
   }

  }

Re: [gl4java-usergroup] Newbie: Using GLJPanel

[Chad S. <sta...@ea...>]

Oops, looks like I spoke too soon.  The gljSwap() works just fine, thank =
you.  It's the gljFree() that was throwing the exception.  Please forget =
all the nonsense that I spouted in my previous email.

Thanks, Chad

PS - This does, however, raise the question "When to use gljFree()?

[gl4java-usergroup] Additional GL4Java docs needed?

[Chad S. <sta...@ea...>]

Hello -

I'm a newbie at both OpenGL, and GL4Java.  However, I've been reading =
the redbook, and using GL4Java to implement a lot of the exercise in the =
redbook.  I had a lot of problems getting GL4Java set up properly =
(mostly due to my inability to read the FAQ), and would like to begin =
writing some docs/tutorial to make the process easier for other =
newbies...

Does anyone think this would be useful?  If so, is there someone who =
would like to house these documents on the website?

Thanks in Advance, Chad
  ----- Original Message -----=20
  From: Chad Stansbury=20
  To: gl4...@li...=20
  Sent: Saturday, June 08, 2002 12:11 PM
  Subject: Re: [gl4java-usergroup] Newbie: Using GLJPanel


  Oops, looks like I spoke too soon.  The gljSwap() works just fine, =
thank you.  It's the gljFree() that was throwing the exception.  Please =
forget all the nonsense that I spouted in my previous email.

  Thanks, Chad

  PS - This does, however, raise the question "When to use gljFree()?

Re: [gl4java-usergroup] Additional GL4Java docs needed?

[Antony R. <an...@li...>]

I'm currently trying to develop a range of tutorials as well.  I also in =
the process of designing some kind of site to house all this info as =
well.

So, I'd be more than happy to put your documents up.

Let me know what you think.

Antony
  ----- Original Message -----=20
  From: Chad Stansbury=20
  To: gl4...@li...=20
  Sent: Wednesday, July 10, 2002 2:27 PM
  Subject: [gl4java-usergroup] Additional GL4Java docs needed?


  Hello -

  I'm a newbie at both OpenGL, and GL4Java.  However, I've been reading =
the redbook, and using GL4Java to implement a lot of the exercise in the =
redbook.  I had a lot of problems getting GL4Java set up properly =
(mostly due to my inability to read the FAQ), and would like to begin =
writing some docs/tutorial to make the process easier for other =
newbies...

  Does anyone think this would be useful?  If so, is there someone who =
would like to house these documents on the website?

  Thanks in Advance, Chad
    ----- Original Message -----=20
    From: Chad Stansbury=20
    To: gl4...@li...=20
    Sent: Saturday, June 08, 2002 12:11 PM
    Subject: Re: [gl4java-usergroup] Newbie: Using GLJPanel


    Oops, looks like I spoke too soon.  The gljSwap() works just fine, =
thank you.  It's the gljFree() that was throwing the exception.  Please =
forget all the nonsense that I spouted in my previous email.

    Thanks, Chad

    PS - This does, however, raise the question "When to use gljFree()?