[osg-users] How to use frame buffer object in existing (not osg) window and pipeline.

[Han Hu]

Hi,

I know OSG viewer can render into other window as shown in the glutviewer and sdl viewer example. But I do not know how to use fbo for this kind of work. The following code describes my purpose.



Code:


osg::ref_ptr<Viewer> viewer;
/* The vierwer is properly set up for other window*/

FrameBufferObject fbo;
/* The fbo is properly initilize with color and depth texture attachment and bind to a FBO object. And the fbo class have access to the texture object and will be used for image based rendering technic*/

/* The rendering loop */
void draw()
{
	// only repaint the whole scene when needed, because my scene is rather static and heavy, 
	// draw fewer things 
	if(dragging){
		fbo.bind();
		/* draw a fewer things into fbo*/
		viewer.frame();        
		fbo.unbind();
	}

	/* Draw heavier things */
	if(need_repaint)
	{
		fbo.bind();
		viewer.frame();
		fbo.unbind();
	}

	/* Do some post processing with fbo, e.g. eye dome lighting, which is  a image based rendering techniqe */
	{
		/* filtering */
		filter(fbo);
	}

	/* blit the fbo onto backbuffer */
	fbo.blit();
	
	swapbuffer();
}





So my question is how to do this kind of fbo processing in OSG, because after investigate osg framebufferobject, I find the logic is not like this and a little confuse to understand. 

Thank you!

Cheers,
Han

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http://forum.openscenegraph.org/viewtopic.php?p=70240#70240