[Qt][OpenGL]framebuffer'ы

    // render the 'bubbles.svg' file into our framebuffer object
    QPainter fbo_painter(render_fbo);
    svg_renderer->render(&fbo_painter);
    fbo_painter.end();

    if (render_fbo != texture_fbo) {
        QRect rect(0, 0, render_fbo->width(), render_fbo->height());
        QGLFramebufferObject::blitFramebuffer(texture_fbo, rect,
                                              render_fbo, rect);
    }

#include <QtOpenGL>
#include <QSvgRenderer>
#include <QtGui/QApplication>
#include <QtGui/QMessageBox>

class GLWidget : public QGLWidget {
    Q_OBJECT
public:
    GLWidget(QWidget *parent) : QGLWidget(QGLFormat(QGL::SampleBuffers|QGL::AlphaChannel), parent) {
      makeCurrent();
      render_fbo = new QGLFramebufferObject(width(), height());
      svg_renderer = new QSvgRenderer(QLatin1String("../bubbles.svg"), this);
      connect(svg_renderer, SIGNAL(repaintNeeded()), this, SLOT(draw()));
    }
    ~GLWidget() { delete render_fbo; }
    void paintEvent(QPaintEvent *) { draw(); }

public slots:
    void draw() {
      // This is required, can't tell why though.
      QPainter painter(this);

      // Target and source rects for blitFramebuffer must be the same for
      // proper rendering, can't tell why either.
      if (render_fbo->width() != width() || render_fbo->height() != height()) {
        delete render_fbo;
        render_fbo = new QGLFramebufferObject(width(), height());
      }

      // render the 'bubbles.svg' file into our framebuffer object
      QPainter fbo_painter(render_fbo);
      svg_renderer->render(&fbo_painter);
      fbo_painter.end();

      QRect rect(0, 0, render_fbo->width(), render_fbo->height());
      QGLFramebufferObject::blitFramebuffer(0, rect, render_fbo, rect);
    }

private:
    QSvgRenderer *svg_renderer;
    QGLFramebufferObject *render_fbo;
};

int main(int argc, char **argv) {
    QApplication a(argc, argv);
    if (!QGLFormat::hasOpenGL() || !QGLFramebufferObject::hasOpenGLFramebufferObjects()) {
        QMessageBox::information(0, "OpenGL framebuffer objects",
         "This system does not support OpenGL/framebuffer objects.");
        return -1;
    }

    GLWidget widget(0);
    widget.resize(640, 480);
    widget.show();
    return a.exec();
}

#include "moc_main.cpp"