[osg-users] Viewer slaves and RTTs

[Johny Canes]

Okay,


Code:

// window / slave
	camera = new osg::Camera();
	osg::Viewport* viewport;

	/// {
	osg::ref_ptr<osg::GraphicsContext::Traits> traits = new osg::GraphicsContext::Traits;
	traits->x = 300 + 0;
	traits->y = 100 + 0;
	traits->width = nr::width;
	traits->height = nr::height;
	traits->windowDecoration = true;
	traits->doubleBuffer = true;
	traits->sharedContext = 0;
	traits->samples = 4; // MSAA
	traits->vsync = false;

	viewport = new osg::Viewport(0, 0, traits->width, traits->height);

	gc = osg::GraphicsContext::createGraphicsContext( traits.get() );
	gc->getState()->setUseModelViewAndProjectionUniforms( true );
	gc->getState()->setUseVertexAttributeAliasing( true );

	GLenum buffer = traits->doubleBuffer ? GL_BACK : GL_FRONT;

	camera = viewer.getCamera();
	camera->setName( "Main" );
	camera->setGraphicsContext( gc.get() );

	camera->setClearColor(osg::Vec4(1.0f, 0.0f, 0.0f, 1.0f));
	camera->setClearMask(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

	camera->setViewport( new osg::Viewport(0, 0, traits->width, traits->height) );
	//camera->getOrCreateStateSet()->setTextureAttributeAndModes( 0, texture, osg::StateAttribute::ON );

	camera->setDrawBuffer( buffer );
	camera->setReadBuffer( buffer );
	camera->setRenderOrder( osg::Camera::RenderOrder::PRE_RENDER );
	//camera->setRenderTargetImplementation( osg::Camera::FRAME_BUFFER_OBJECT );
	
	camera->attach( osg::Camera::COLOR_BUFFER0, texture );
	//camera->attach( osg::Camera::COLOR_BUFFER, texture, 0, 0, false, 0, 0 );

	//viewer.addSlave( camera, osg::Matrix(), osg::Matrix() );

	//viewer.setCamera( camera ); // unnecessary / messes up z-ordering ...

	//camera->addChild( root.get() );
	/// }




This makes a window. I get it that a window is backed by a camera / GC.

So naturally, since I'm using the original camera, my camera, 'Main', will render to its window. It would be ideal to turn this off, and only have this camera render to a hidden buffer (FBO?). Using a pbuffer / pbuffer-rtt is overkill and I'm not sure I understand that approach.

Cheers,
Johny

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