why is this code crashing ?

Programming Questions

motscousus

in Programming Questions • 2 years ago

Hi all,

i am trying to have a second window (to display a preview of the main windows using FBO like explained here : http://processing.org/discourse/yabb2/YaBB.pl?num=1207160412/15 )

but the code is crashing : java JVM crashes with no message (i am on windows 7 32bits java 1.6_021 with nvidia video card)

the crash seems to be related to attaching the GLCanvas to the JFrame and displaying it. (displaying the windows without attaching the canvas to it, or not displaying the window seems not to crash).

any idea ?

henri

import java.awt.Frame;
import javax.media.opengl.*;
import com.sun.opengl.util.FPSAnimator;

void setup(){
size(100,100,OPENGL);
PreviewFrame frame = new PreviewFrame();
}

void draw(){
}

public class PreviewFrame {

    GLCanvas canvas;

    public PreviewFrame() {
        Frame f = new Frame("preview");
        GLCanvas canvas = new GLCanvas();
        canvas.addGLEventListener(new GLRenderer());
        f.add(canvas);
        f.setSize(300, 300);
        FPSAnimator animator = new FPSAnimator(canvas, 60);
        animator.start();
        f.setVisible(true);
    }

    class GLRenderer implements GLEventListener {
        GL gl;

        public void init(GLAutoDrawable drawable) {
            this.gl = drawable.getGL();
            gl.glClearColor(0, 0, 0, 0);
        }

        public void display(GLAutoDrawable drawable) {
            gl.glClear(GL.GL_COLOR_BUFFER_BIT | GL.GL_DEPTH_BUFFER_BIT );
            gl.glColor3f(random(1), random(1), random(1));
            gl.glRectf(-0.8f, 0.8f, 50%random(100)/100f* -0.8f, 0.7f);
        }

        public void reshape(GLAutoDrawable drawable, int x, int y, int width, int height) {
        }

        public void displayChanged(GLAutoDrawable drawable, boolean modeChanged, boolean deviceChanged) {
        }
    }
}

Replies(7)

monkstone

Re: why is this code crashing ?

2 years ago

Could it be because you are not accessing jogl correctly?

PGraphicsOpenGL pgl = (PGraphicsOpenGL) g;

  GL gl = pgl.beginGL();  // always use the GL object returned by beginGL

motscousus

Re: why is this code crashing ?

2 years ago

unfortunatly no.. because this code that does not call gl at all crashes too.

the problem is more with showing the frame and GLCanvas

import java.awt.Frame;
import processing.opengl.*;
import javax.media.opengl.*;
import com.sun.opengl.util.FPSAnimator;

void setup(){
size(100,100,OPENGL);
PreviewFrame frame = new PreviewFrame();
}

void draw(){
}

public class PreviewFrame {
    GLCanvas canvas;
    public PreviewFrame() {
        Frame f = new Frame("preview");
        GLCanvas canvas = new GLCanvas();
        canvas.addGLEventListener(new GLRenderer());
        f.add(canvas);
        f.setSize(300, 300);
        FPSAnimator animator = new FPSAnimator(canvas, 60);
        animator.start();
        f.setVisible(true);
    }

    class GLRenderer implements GLEventListener {
        public void init(GLAutoDrawable drawable) {
        }
        public void display(GLAutoDrawable drawable) {
        }
        public void reshape(GLAutoDrawable drawable, int x, int y, int width, int height) {
        }
        public void displayChanged(GLAutoDrawable drawable, boolean modeChanged, boolean deviceChanged) {
        }
    }
}

monkstone

Re: Re: why is this code crashing ?

2 years ago

Well I got something to run, but I also changed a few other things, like in Preview frame you re-declare canvas as GLCanvas.

motscousus

Re: why is this code crashing ?

2 years ago

my idea is to have the main window on a projector and this new frame as a preview on my screen during the performance.
i though of doing so using FBO and RenderToTexture technics. therefore i though i should have a new canvas in my previewing frame. but i an not sure if i can share the same gl object for both windows. that is where my openGL knowledge stops :/

i would be happy to see your code if you get something running !

Also, trying to run the example from the doc i got a similar crash http://wiki.processing.org/w/Using_JOGL_directly

any idea where to start looking ?

h

monkstone

Re: Re: why is this code crashing ?

2 years ago

This is the code I got to work, I don't know whether your idea is likely to work or not.

import processing.opengl.*;
import java.awt.*;
import javax.media.opengl.GLCapabilities;
import javax.media.opengl.GLCanvas;
import javax.media.opengl.GLEventListener;
import javax.media.opengl.GLAutoDrawable;
import javax.media.opengl.GL;
import com.sun.opengl.util.FPSAnimator;
void setup() {
size(100,100,OPENGL);
PreviewFrame frame = new PreviewFrame();
}
void draw() {
}
class PreviewFrame {
GLCanvas canvas;
PreviewFrame() {
GLCapabilities capab = new GLCapabilities();
Frame f = new Frame("preview");
canvas = new GLCanvas(capab);
canvas.addGLEventListener(new GLRenderer());
f.add(canvas);
f.setSize(300, 300);
FPSAnimator animator = new FPSAnimator(canvas, 60);
animator.start();
f.setVisible(true);
}
class GLRenderer implements GLEventListener {
PGraphicsOpenGL pgl = (PGraphicsOpenGL) g; // g may change
GL gl = pgl.beginGL();
public void init(GLAutoDrawable drawable) {
this.gl = drawable.getGL();
gl.glClearColor(0, 0, 0, 0);
}
public void display(GLAutoDrawable drawable) {
gl.glClear(GL.GL_COLOR_BUFFER_BIT | GL.GL_DEPTH_BUFFER_BIT );
gl.glColor3f(random(1), random(1), random(1));
gl.glRectf(-0.8f, 0.8f, 50%random(100)/100f* -0.8f, 0.7f);
}
public void reshape(GLAutoDrawable drawable, int x, int y, int width, int height) {
}
public void displayChanged(GLAutoDrawable drawable, boolean modeChanged, boolean deviceChanged) {
}
}
}

motscousus

Re: why is this code crashing ?

2 years ago

thanks a lot ! it was needed to init gl in the previewFrame too. missed that...

i tried to integrate this into a proof of concept, but it seems it does not work. i suspect the FBO and texture are not shared across gl instances (one for the main window and one for the previewFrame)

motscousus

Re: why is this code crashing ?

2 years ago

following another thread on the same topic i found a solution that works and seems pretty fast using GLGraphics :
http://forum.processing.org/topic/second-monitor-window-and-optimizing-performance#25080000000382015

now dealing with some issue with texture size and position, aspect ratio etc... but it looks fine :)

thanks for you help.

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