Render to VBO

OpenGL Development JOGL Development
#1

Hello, Y’m implemetoing some renter to VBO with JOGL. I’m using the method:

  • Render to FBO
  • Transfer to VBO

The code in javais just a JOGLversion of the that I use in C++:


//Inside  transferiDatos()
        this.sistemaGrafico.glBindFramebufferEXT( GL.GL_FRAMEBUFFER_EXT, fbo.ID[0]);
        this.sistemaGrafico.glReadBuffer( GL.GL_COLOR_ATTACHMENT0_EXT );
        
        this.sistemaGrafico.glBindBuffer(GL.GL_PIXEL_PACK_BUFFER, vbo[0]);
	this.sistemaGrafico.glBufferData(GL.GL_PIXEL_PACK_BUFFER, fbo.width*fbo.height*4*4,null, GL.GL_STATIC_DRAW );
	
	this.sistemaGrafico.glReadPixels( 0,0, fbo.width, fbo.height, GL.GL_RGBA, GL.GL_FLOAT,null);
	
	this.sistemaGrafico.glReadBuffer(GL.GL_NONE);
	this.sistemaGrafico.glBindBuffer(GL.GL_PIXEL_PACK_BUFFER, 0 );

, where this.sistemaGrafico is a GL object. But I’m getting this exception:


Exception in thread "AWT-EventQueue-0" javax.media.opengl.GLException: pack pixel_buffer_object must be disabled to call this method
        at com.sun.opengl.impl.GLImpl.checkBufferObject(GLImpl.java:30668)
        at com.sun.opengl.impl.GLImpl.checkPackPBODisabled(GLImpl.java:30695)
        at com.sun.opengl.impl.GLImpl.glReadPixels(GLImpl.java:17459)
        at com.fractal.Aplicacion.transferirDatos(Aplicacion.java:374)
        at com.fractal.Aplicacion.hazTodoElCalculo(Aplicacion.java:153)
        at com.fractal.Aplicacion.init(Aplicacion.java:451)
        at com.sun.opengl.impl.GLDrawableHelper.init(GLDrawableHelper.java:72)
        at javax.media.opengl.GLCanvas$InitAction.run(GLCanvas.java:418)
        at com.sun.opengl.impl.GLDrawableHelper.invokeGL(GLDrawableHelper.java:189)
        at javax.media.opengl.GLCanvas.maybeDoSingleThreadedWorkaround(GLCanvas.java:412)
        at javax.media.opengl.GLCanvas.display(GLCanvas.java:244)
        at javax.media.opengl.GLCanvas.paint(GLCanvas.java:277)
        at sun.awt.RepaintArea.paintComponent(RepaintArea.java:248)
        at sun.awt.X11.XRepaintArea.paintComponent(XRepaintArea.java:56)
        at sun.awt.RepaintArea.paint(RepaintArea.java:224)
        at sun.awt.X11.XComponentPeer.handleEvent(XComponentPeer.java:683)
        at java.awt.Component.dispatchEventImpl(Component.java:4486)
        at java.awt.Component.dispatchEvent(Component.java:4240)
        at java.awt.EventQueue.dispatchEvent(EventQueue.java:599)
        at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:273)
        at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:183)
        at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:173)
        at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:168)
        at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:160)
        at java.awt.EventDispatchThread.run(EventDispatchThread.java:121)

I don’t know what is going on. Please, some help please.

http://www.raul-art.blogspot.com/

#2

Hi!
weel, I’ve solved the problem. Instead of sending NULL in the call glBufferData(), I use 0.
(Until now I didn’t know Java can accept int values where a object is expected )
Why this is different to many other parts of JOGL API.

#3

You probably don’t realize what actually happened.

There is this feasture called ‘autoboxing’ in Java now. It wraps primitives into objects, when this is required to make a compilation successful.

Like:

Map<Integer, Integer> map = …;
map.put(13, 14); // this is changed to: map.put(Integer.valueOf(13), Integer.valueOf(14));

In your case, if the method is like:
glBufferData(…, Object obj);
and you call
glBufferData(…, 0);
you effectively call
glBufferData(…, Integer.valueOf(0));
which is probably not what you expected.

if
glBufferData(…, int off);
exists, it’s all fine ofcourse.

#4

Ugh, don’t you just hate auto-boxing?
If I would have a say in it, I’d take autoboxing out of java yesterday.

#5

Yup, and give us all permutations of Lists, Sets and Maps please :slight_smile:

#6

thank you all, I did’nt know that! and thanks for your opinions too, I will investigate more on line.

Bye!