QNoDraw Class | Qt 3D 5.12.9

- Qt 5.12
- Qt 3D
- C++ Classes
- QNoDraw
- Qt 5.12.9 Reference Documentation

# QNoDraw 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

- List of all members, including inherited members
- Obsolete members

## Public Functions

| QNoDraw(Qt3DCore::QNode *parent = nullptr)

- 1 public function inherited from Qt3DRender::QFrameGraphNode
- 13 public functions inherited from Qt3DCore::QNode
- 31 public functions inherited from QObject

## Static Public Members

const QMetaObject | staticMetaObject

- 9 static public members inherited from QObject

### Additional Inherited Members

- 3 properties inherited from Qt3DCore::QNode
- 1 property inherited from QObject
- 3 public slots inherited from Qt3DCore::QNode
- 1 public slot inherited from QObject
- 4 signals inherited from Qt3DCore::QNode
- 2 signals inherited from QObject
- 1 protected function inherited from Qt3DRender::QFrameGraphNode
- 2 protected functions inherited from Qt3DCore::QNode
- 9 protected functions inherited from QObject

## Detailed Description

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

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);
     ....

## Member Function Documentation

### QNoDraw::QNoDraw(Qt3DCore::QNode *parent = nullptr)

The constructor creates an instance with the specified parent.