QRhi software-rendering example

skinkie

I am trying to find a working example where QSGRendererInterface::Software independent of any OpenGL requirement would work for offscreen rendering.

m_renderControl = new QQuickRenderControl();
m_quickWindow = new QQuickWindow(m_renderControl);
m_quickWindow->setGraphicsApi(QSGRendererInterface::Software);

QImage qimage = QImage(1920, 1080, QImage::Format_ARGB32);
QQuickRenderTarget renderTarget = QQuickRenderTarget::fromPaintDevice(&qimage);
m_quickWindow->setRenderTarget(renderTarget);

m_renderControl->beginFrame();
m_renderControl->render();
m_renderControl->endFrame();

I end up with:

QQuickRenderControl: No QRhi in beginFrame()
QQuickRenderControl: No QRhi in endFrame()

QKelteseth

So the solution here is not to use QRhi but the OpenGL api and setting

QCoreApplication::setAttribute(Qt::AA_UseSoftwareOpenGL);

to force LLVMPipe OpenGL software rendering

https://doc.qt.io/qt-6/qtquick-rendercontrol-rendercontrol-rhi-example.html