gistfile1.txt

arstudio::ItemViewRenderer * ItemView::createRenderer() const
{
    return new ItemViewRenderer;
}

=======

#ifndef ITEM_VIEW_RENDERER_H
#define ITEM_VIEW_RENDERER_H

//#include <ItemView.hpp>
#include <KeyboardCameraManipulator.hpp>

#include <QOpenGLFramebufferObject>
#include <QOpenGLFunctions>
#include <QQuickFramebufferObject>

#include <osgViewer/Viewer>
#include <osgViewer/Renderer>
#include <osgGA/OrbitManipulator>
#include <osg/ShapeDrawable>
#include <osg/Geometry>
#include <osg/LineWidth>
#include <osgText/Text>

#include <QtDebug>

namespace arstudio {

class ItemViewRenderer : public QQuickFramebufferObject::Renderer
{
public:
    ItemViewRenderer();

    QOpenGLFramebufferObject * createFramebufferObject(const QSize &size);
    void render();
    void synchronize(QQuickFramebufferObject * item);
private:
    void osg_initialize();

    void create_axis ();

    QSize m_size;
    QOpenGLFramebufferObject * m_fbo;

    osg::ref_ptr<osgViewer::Viewer>                 m_osg_viewer;
    osg::ref_ptr<osgGA::OrbitManipulator>           m_osg_orbit;
    osg::ref_ptr<KeyboardCameraManipulator>         m_osg_firstperson;
    osg::ref_ptr<osg::Group>                        m_osg_scene;
    osg::ref_ptr<osgViewer::GraphicsWindowEmbedded> m_osg_window_handle;
    /*
     * we will not delete this in the destructor, should be deleted internally by
     * OSG since osg::Geode derives Referenced; TODO: verify?
     */
    osg::Geode * m_sequence_node;

};

}
#endif // ITEM_VIEW_RENDERER_H


=======

#include <ItemViewRenderer.hpp>

namespace arstudio {

ItemViewRenderer::ItemViewRenderer()
    : QQuickFramebufferObject::Renderer()
    , m_fbo(nullptr)
{
    osg_initialize();
    qDebug() << __FUNCTION__;
}

QOpenGLFramebufferObject *
ItemViewRenderer::createFramebufferObject(const QSize &size)
{
    qDebug() << __FUNCTION__;

    QOpenGLFramebufferObjectFormat format;
    format.setAttachment (QOpenGLFramebufferObject::CombinedDepthStencil);

    m_fbo = new QOpenGLFramebufferObject (size, format);
    int w = size.width(), h = size.height();

    auto handle = m_osg_viewer->setUpViewerAsEmbeddedInWindow (0, 0, w, h);
    osg::Camera * c = m_osg_viewer->getCamera ();

    handle->resized (0, 0, w, h);
    c->setViewport (0, 0, w, h);
    c->setProjectionMatrixAsPerspective (30.0f, (float) w / h, 1.0f, 10000.0f);

    return m_fbo;
}

void ItemViewRenderer::render()
{
    QOpenGLFunctions f (QOpenGLContext::currentContext ());

    // непонятный костыль
    f.glUseProgram(0);
    f.glDisable(GL_DEPTH_TEST);
    f.glDisable(GL_BLEND);

    // actual OSG rendering happens here
    m_osg_viewer->frame ();

    qDebug() << __FUNCTION__;
}

void ItemViewRenderer::synchronize(QQuickFramebufferObject *item)
{
    qDebug() << __FUNCTION__;

}

void ItemViewRenderer::osg_initialize()
{
    m_osg_viewer = new osgViewer::Viewer;
    m_osg_viewer->setThreadingModel (osgViewer::Viewer::SingleThreaded);

    osg::Light * light = m_osg_viewer->getLight ();
    light->setAmbient (osg::Vec4 (.2, .2, .2, .2));

    osg::Camera * camera = m_osg_viewer->getCamera ();
    // background color for whatever is rendered with OSG
    camera->setClearColor (osg::Vec4 (.05, .05, .05, 1.0));

    m_osg_orbit = new osgGA::OrbitManipulator;
    constexpr int flags = KeyboardCameraManipulator::UPDATE_MODEL_SIZE;
    m_osg_firstperson = new KeyboardCameraManipulator (flags);
    m_osg_firstperson->setVelocity (0.05);

    m_osg_firstperson->setHomePosition (osg::Vec3 (3, 0, 3), osg::Vec3 (0, 0, 0),
                                        osg::Vec3 (0, 0, 1));

    m_osg_orbit->setHomePosition (osg::Vec3 (3, 0, 3), osg::Vec3 (0, 0, 0),
                                  osg::Vec3 (0, 0, 1));
    // stop spinning when releasing LMB while moving the mouse
    m_osg_orbit->setAllowThrow (false);

    m_osg_viewer->setCameraManipulator (m_osg_orbit.get ());
    m_osg_viewer->home ();

    m_osg_scene     = new osg::Group;
    m_sequence_node = new osg::Geode;
    m_osg_scene->addChild (m_sequence_node);
    m_osg_viewer->setSceneData (m_osg_scene.get ());

    create_axis();
}

void
ItemViewRenderer::create_axis ()
{
  osg::Geode         * axis = new osg::Geode;
  osg::ShapeDrawable * s;
  osg::Cylinder      * cyl;
  osg::Cone          * cone;
  // cylinder radius
  constexpr float cr = 0.01;
  // cone height
  constexpr float ch = 8 * cr;

  // Z arrow
  cyl = new osg::Cylinder (osg::Vec3 (0, 0, 0.5), cr, 1);
  s   = new osg::ShapeDrawable (cyl);
  axis->addDrawable (s);
  cone = new osg::Cone (osg::Vec3 (0, 0, 1), 2 * cr, ch);
  s    = new osg::ShapeDrawable (cone);
  s->setColor (osg::Vec4 (0, 0, .9, 1.0));
  axis->addDrawable (s);
//  axis->addDrawable (show_text (osg::Vec3 (0, 0, 1.1), "Z"));

  // X arrow
  cyl = new osg::Cylinder (osg::Vec3 (0.5, 0, 0), cr, 1);
  s   = new osg::ShapeDrawable (cyl);
  cyl->setRotation (osg::Quat (M_PI_2, osg::Vec3 (0, 1, 0)));
  axis->addDrawable (s);
  cone = new osg::Cone (osg::Vec3 (1, 0, 0), 2 * cr, ch);
  s    = new osg::ShapeDrawable (cone);
  cone->setRotation (osg::Quat (M_PI_2, osg::Vec3 (0, 1, 0)));
  s->setColor (osg::Vec4 (.9, .9, 0, 1.0));
  axis->addDrawable (s);
//  axis->addDrawable (show_text (osg::Vec3 (1.1, 0, 0), "X"));

  // Y arrow
  cyl = new osg::Cylinder (osg::Vec3 (0, 0.5, 0), cr, 1);
  s   = new osg::ShapeDrawable (cyl);
  cyl->setRotation (osg::Quat (M_PI_2, osg::Vec3 (1, 0, 0)));
  axis->addDrawable (s);
  cone = new osg::Cone (osg::Vec3 (0, 1, 0), 2 * cr, ch);
  s    = new osg::ShapeDrawable (cone);
  cone->setRotation (osg::Quat (-M_PI_2, osg::Vec3 (1, 0, 0)));
  s->setColor (osg::Vec4 (.9, 0, 0, 1.0));
  axis->addDrawable (s);
//  axis->addDrawable (show_text (osg::Vec3 (0, 1.1, 0), "Y"));

  m_osg_scene->addChild (axis);
}

}

Hi, just found your snippet while looking for a convenient way to render a osg scene in a qtquick item. Tried your snippet, but could not get the osg content rendered correctly (first frame black, after re-sizing buffer stays the same). I suppose it has something to do with the OpenGL Context State of OSG. Did you have the same issue?