#include <QOpenGLFramebufferObjectFormat>

#include <QQuickOpenGLUtils>

class GameViewRenderer : public QQuickFramebufferObject::Renderer {

 public:

  explicit GameViewRenderer() = default;

  GameViewRenderer(const GameViewRenderer&) = delete;

  GameViewRenderer(GameViewRenderer&&) = delete;

  GameViewRenderer& operator=(const GameViewRenderer&) = delete;

  GameViewRenderer& operator=(GameViewRenderer&&) = delete;

  void render() override;

  QOpenGLFramebufferObject* createFramebufferObject(const QSize& size) override;

  void synchronize(QQuickFramebufferObject* fbo) override;

  QPointer<GameView> m_gameView;

  QPointer<QQuickWindow> m_window;

  bool m_inited{false};

};

void GameViewRenderer::render() {

  const auto engine = m_gameView->engineInstance();

  if (!engine) {

    return;

  }

  if (!m_inited) {

    m_inited = true;

    engine->setOpenGLContext(QOpenGLContext::currentContext());

  }

  engine->renderFrame();

  QQuickOpenGLUtils::resetOpenGLState();

}

QOpenGLFramebufferObject* GameViewRenderer::createFramebufferObject(

    const QSize& size) {

  QOpenGLFramebufferObjectFormat format;

  format.setAttachment(QOpenGLFramebufferObject::CombinedDepthStencil);

  format.setSamples(8);

  auto fbo = new QOpenGLFramebufferObject(size, format);

  return fbo;

}

void GameViewRenderer::synchronize(QQuickFramebufferObject* fbo) {

  if (!m_gameView) {

    m_gameView = qobject_cast<GameView*>(fbo);

    m_window = fbo->window();

  }

}

    : QQuickFramebufferObject(parent), m_delta(0) {

  setMirrorVertically(true);

    connect(timer, &QTimer::timeout, this, &GameView::update);

QQuickFramebufferObject::Renderer* GameView::createRenderer() const {

  return new GameViewRenderer{};

  Q_EMIT engineInstanceChanged(m_engineInstance);