Qt3DRender.QLevelOfDetail

The QLevelOfDetail class provides a way of controlling the complexity of rendered entities based on their size on the screen. More…

Inherited by: Qt3DRender.QLevelOfDetailSwitch

Synopsis

Functions

• def camera ()

• def createBoundingSphere (center, radius)

• def currentIndex ()

• def thresholdType ()

• def thresholds ()

• def volumeOverride ()

Slots

• def setCamera (camera)

• def setCurrentIndex (currentIndex)

• def setThresholdType (thresholdType)

• def setThresholds (thresholds)

• def setVolumeOverride (volumeOverride)

Signals

• def cameraChanged (camera)

• def currentIndexChanged (currentIndex)

• def thresholdTypeChanged (thresholdType)

• def thresholdsChanged (thresholds)

• def volumeOverrideChanged (volumeOverride)

Detailed Description

QLevelOfDetail can be used to control the representation of an entity based on distance from the observer or size on the screen.

In order to improve rendering performance, objects that are very small can be rendered using far fewer details, in geometry or texture.

The component is controlled by specifying thresholds of values which are interpreted as either distances from the camera or screen size.

As the point of view changes, the currentIndex property will change to reflect matching value in the range array.

The currentIndex property can then be used, for example, to enable or disable entities, change material, etc.

The LevelOfDetail component is not shareable between multiple entities .

 #include <Qt3DCore/QEntity>
 #include <Qt3DRender/QGeometryRenderer>
 #include <Qt3DRender/QLevelOfDetail>

// Scene
Qt3DCore::QEntity *rootEntity = new Qt3DCore::Qt3DCore::QEntity;

Qt3DCore::QEntity *renderableEntity = new Qt3DCore::QEntity(rootEntity);
Qt3DRender::QGeometryRenderer *geometryRenderer = new Qt3DCore::QGeometryRenderer(renderableEntity);
renderableEntity->addComponent(geometryRenderer);
Qt3DRender::QLevelOfDetail* lod = new Qt3Render::QLevelOfDetail(renderableEntity);
QVector<qreal> thresholds = {20, 35, 50, 65};
lod->setThresholds(thresholds);
lod->setCamera(mainCamera);
renderableEntity->addComponent(lod);

// connect to QLevelOfDetail::currentIndexChanged to toggle rendering
...

class PySide2.Qt3DRender.Qt3DRender.QLevelOfDetail([parent=None])

param parent

QNode

Constructs a new QLevelOfDetail with the specified parent .

PySide2.Qt3DRender.Qt3DRender.QLevelOfDetail.ThresholdType

Specifies how the values in the thresholds are interpreted

Constant	Description
Qt3DRender.QLevelOfDetail.DistanceToCameraThreshold	Distance from the entity to the selected camera
Qt3DRender.QLevelOfDetail.ProjectedScreenPixelSizeThreshold	Size of the entity when projected on the screen as seen from the selected camera, expressed in number of pixels on the side of the bounding square in screen space.

PySide2.Qt3DRender.Qt3DRender.QLevelOfDetail.camera()

Return type

QCamera

See also

setCamera()

PySide2.Qt3DRender.Qt3DRender.QLevelOfDetail.cameraChanged(camera)

Parameters

camera – QCamera

PySide2.Qt3DRender.Qt3DRender.QLevelOfDetail.createBoundingSphere(center, radius)

Parameters

• center – QVector3D

• radius – float

Return type

QLevelOfDetailBoundingSphere

PySide2.Qt3DRender.Qt3DRender.QLevelOfDetail.currentIndex()

Return type

int

See also

setCurrentIndex()

PySide2.Qt3DRender.Qt3DRender.QLevelOfDetail.currentIndexChanged(currentIndex)

Parameters

currentIndex – int

PySide2.Qt3DRender.Qt3DRender.QLevelOfDetail.setCamera(camera)

Parameters

camera – QCamera

Sets the camera relative to which distance and size are computed.

See also

camera()

PySide2.Qt3DRender.Qt3DRender.QLevelOfDetail.setCurrentIndex(currentIndex)

Parameters

currentIndex – int

Sets the currentIndex .

Note

This should not normally be set by the user.

However, if the component is disabled, then changing the current index is a simple way of switching between multiple representations.

See also

currentIndex()

PySide2.Qt3DRender.Qt3DRender.QLevelOfDetail.setThresholdType(thresholdType)

Parameters

thresholdType – ThresholdType

Sets the way thresholds values are interpreted with parameter thresholdType

See also

thresholdType() ThresholdType

PySide2.Qt3DRender.Qt3DRender.QLevelOfDetail.setThresholds(thresholds)

Parameters

thresholds –

Sets the range values in thresholds .

See also

thresholds() thresholdType

PySide2.Qt3DRender.Qt3DRender.QLevelOfDetail.setVolumeOverride(volumeOverride)

Parameters

volumeOverride – QLevelOfDetailBoundingSphere

See also

volumeOverride()

PySide2.Qt3DRender.Qt3DRender.QLevelOfDetail.thresholdType()

Return type

ThresholdType

See also

setThresholdType()

PySide2.Qt3DRender.Qt3DRender.QLevelOfDetail.thresholdTypeChanged(thresholdType)

Parameters

thresholdType – ThresholdType

PySide2.Qt3DRender.Qt3DRender.QLevelOfDetail.thresholds()

Return type

See also

setThresholds()

PySide2.Qt3DRender.Qt3DRender.QLevelOfDetail.thresholdsChanged(thresholds)

Parameters

thresholds –

PySide2.Qt3DRender.Qt3DRender.QLevelOfDetail.volumeOverride()

Return type

QLevelOfDetailBoundingSphere

See also

setVolumeOverride()

PySide2.Qt3DRender.Qt3DRender.QLevelOfDetail.volumeOverrideChanged(volumeOverride)

Parameters

volumeOverride – QLevelOfDetailBoundingSphere