- Qt 5.15
- Qt 3D
- C++ Classes
- QNoDraw
- Qt 5.15.11 Reference Documentation

# QNoDraw Class

class Qt3DRender::QNoDraw

When a Qt3DRender::QNoDraw node is present in a FrameGraph branch, this prevents the renderer from rendering any primitive. More...

Header: | #include <QNoDraw>
qmake: | QT += 3drender
Since: | Qt 5.5
Instantiated By: | NoDraw
Inherits: | Qt3DRender::QFrameGraphNode

This class was introduced in Qt 5.5.

- List of all members, including inherited members

## Detailed Description

Qt3DRender::QNoDraw should be used when the FrameGraph needs to set up some render states or clear some buffers without requiring any mesh to be drawn. It has the same effect as having a Qt3DRender::QRenderPassFilter that matches none of available Qt3DRender::QRenderPass instances of the scene without the overhead cost of actually performing the filtering.

When disabled, a Qt3DRender::QNoDraw node won't prevent the scene from being rendered. Toggling the enabled property is therefore a way to make a Qt3DRender::QNoDraw active or inactive.

Qt3DRender::QNoDraw is usually used as a child of a Qt3DRendeR::QClearBuffers node to prevent from drawing the scene when there are multiple render passes.

     Qt3DRender::QViewport *viewport = new Qt3DRender::QViewport();
     Qt3DRender::QCameraSelector *cameraSelector = new Qt3DRender::QCameraSelector(viewport);

     Qt3DRender::QClearBuffers *clearBuffers = new Qt3DRender::QClearBuffers(cameraSelector);
     clearBuffers->setBuffers(Qt3DRender::QClearBuffers::ColorDepthBuffer);

     Qt3DRender::QNoDraw *noDraw = new Qt3DRender::QNoDraw(clearBuffers);

     Qt3DRender::QRenderPassFilter *mainPass = new Qt3DRender::QRenderPassFilter(cameraSelector);
     ....
     Qt3DRender::QRenderPassFilter *previewPass = new Qt3DRender::QRenderPassFilter(cameraSelector);
     ....