內容

• 公共類型
• 特性
• 公共函數
• 公共槽
• 信號
• 靜態公共成員
• 詳細描述

QLevelOfDetail Class

( Qt3DRender::QLevelOfDetail )

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

頭：	#include <QLevelOfDetail>
qmake:	QT += 3drender
Since:	Qt 5.9
實例化：	LevelOfDetail
繼承：	Qt3DCore::QComponent
繼承者：	Qt3DRender::QLevelOfDetailSwitch

• 所有成員列錶，包括繼承成員
• 過時成員

公共類型

enum	ThresholdType { DistanceToCameraThreshold, ProjectedScreenPixelSizeThreshold }

特性

camera : Qt3DRender::QCamera* currentIndex : int thresholdType : ThresholdType

thresholds : QVector<qreal> volumeOverride : Qt3DRender::QLevelOfDetailBoundingSphere

• 1 特性繼承自 Qt3DCore::QComponent
• 3 特性繼承自 Qt3DCore::QNode
• 1 特性繼承自 QObject

公共函數

	QLevelOfDetail (Qt3DCore::QNode * parent = nullptr)
Qt3DRender::QCamera *	camera () const
Qt3DRender::QLevelOfDetailBoundingSphere	createBoundingSphere (const QVector3D & center , float radius )
int	currentIndex () const
Qt3DRender::QLevelOfDetail::ThresholdType	thresholdType () const
QVector<qreal>	thresholds () const
Qt3DRender::QLevelOfDetailBoundingSphere	volumeOverride () const

• 2 公共函數繼承自 Qt3DCore::QComponent
• 13 公共函數繼承自 Qt3DCore::QNode
• 31 公共函數繼承自 QObject

公共槽

void	setCamera (Qt3DRender::QCamera * camera )
void	setCurrentIndex (int currentIndex )
void	setThresholdType (Qt3DRender::QLevelOfDetail::ThresholdType thresholdType )
void	setThresholds (const QVector<qreal> & thresholds )
void	setVolumeOverride (const Qt3DRender::QLevelOfDetailBoundingSphere & volumeOverride )

• 1 公共槽繼承自 Qt3DCore::QComponent
• 3 公共槽繼承自 Qt3DCore::QNode
• 1 公共槽繼承自 QObject

信號

void	cameraChanged (Qt3DRender::QCamera * camera )
void	currentIndexChanged (int currentIndex )
void	thresholdTypeChanged (Qt3DRender::QLevelOfDetail::ThresholdType thresholdType )
void	thresholdsChanged (const QVector<qreal> & thresholds )
void	volumeOverrideChanged (const Qt3DRender::QLevelOfDetailBoundingSphere & volumeOverride )

• 3 信號繼承自 Qt3DCore::QComponent
• 4 信號繼承自 Qt3DCore::QNode
• 2 信號繼承自 QObject

靜態公共成員

const QMetaObject

staticMetaObject

• 9 靜態公共成員繼承自 QObject

額外繼承成員

• 2 保護函數繼承自 Qt3DCore::QNode
• 9 保護函數繼承自 QObject

詳細描述

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

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
...
					

成員類型文檔編製

enum QLevelOfDetail:: ThresholdType

Specifies how the values in the thresholds are interpreted

常量	值	描述
Qt3DRender::QLevelOfDetail::DistanceToCameraThreshold	0	Distance from the entity to the selected camera
Qt3DRender::QLevelOfDetail::ProjectedScreenPixelSizeThreshold	1	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.

特性文檔編製

camera : Qt3DRender::QCamera *

Holds the id of the camera that is used to compute the actual distance or the screen size.

訪問函數：

Qt3DRender::QCamera *	camera () const
void	setCamera (Qt3DRender::QCamera * camera )

通知程序信號：

void	cameraChanged (Qt3DRender::QCamera * camera )

currentIndex : int

The index in the range array which matches the current distance to the camera or screen size.

訪問函數：

int	currentIndex () const
void	setCurrentIndex (int currentIndex )

通知程序信號：

void	currentIndexChanged (int currentIndex )

thresholdType : ThresholdType

Specifies how range values are interpreted.

訪問函數：

Qt3DRender::QLevelOfDetail::ThresholdType	thresholdType () const
void	setThresholdType (Qt3DRender::QLevelOfDetail::ThresholdType thresholdType )

通知程序信號：

void	thresholdTypeChanged (Qt3DRender::QLevelOfDetail::ThresholdType thresholdType )

另請參閱 Qt3DRender::QLevelOfDetail::ThresholdType .

thresholds : QVector < qreal >

Array of range values as float point numbers. The value for the most detailed representation should be specified first.

若 Qt3DRender::QLevelOfDetail::thresholdType 被設為 Qt3DRender::QLevelOfDetail::DistanceToCameraThreshold , values should be specified in ascending order, in camera space coordinates

若 Qt3DRender::QLevelOfDetail::thresholdType 被設為 Qt3DRender::QLevelOfDetail::ProjectedScreenPixelSizeThreshold , values should be specified in descending order, in screen space pixels.

訪問函數：

QVector<qreal>	thresholds () const
void	setThresholds (const QVector<qreal> & thresholds )

通知程序信號：

void	thresholdsChanged (const QVector<qreal> & thresholds )

另請參閱 Qt3DRender::QLevelOfDetail::ThresholdType .

volumeOverride : Qt3DRender::QLevelOfDetailBoundingSphere

The default is a sphere of radius 1 and centered at the local origin of the entity. This proxy volume is used to compute the distance to the camera or the size of the screen projection.

If this value to nullptr, the bounding volume of the entity is used. Care must be taken that this bounding volume never becomes invalid.

訪問函數：

Qt3DRender::QLevelOfDetailBoundingSphere	volumeOverride () const
void	setVolumeOverride (const Qt3DRender::QLevelOfDetailBoundingSphere & volumeOverride )

通知程序信號：

void	volumeOverrideChanged (const Qt3DRender::QLevelOfDetailBoundingSphere & volumeOverride )

另請參閱 Qt3DRender::QLevelOfDetailBoundingSphere .

成員函數文檔編製

QLevelOfDetail:: QLevelOfDetail ( Qt3DCore::QNode * parent = nullptr)

構造新的 QLevelOfDetail 采用指定 parent .

Qt3DRender::QLevelOfDetailBoundingSphere QLevelOfDetail:: createBoundingSphere (const QVector3D & center , float radius )

注意： 此函數可以被援引，通過元對象係統和從 QML。見 Q_INVOKABLE .

[slot] void QLevelOfDetail:: setCamera ( Qt3DRender::QCamera * camera )

設置 camera relative to which distance and size are computed.

注意： setter 函數對於特性 camera .

另請參閱 camera ().

[slot] void QLevelOfDetail:: setCurrentIndex ( int currentIndex )

設置 currentIndex .

注意： 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.

注意： setter 函數對於特性 currentIndex .

另請參閱 currentIndex ().

[slot] void QLevelOfDetail:: setThresholdType ( Qt3DRender::QLevelOfDetail::ThresholdType thresholdType )

Sets the way thresholds values are interpreted with parameter thresholdType

注意： setter 函數對於特性 thresholdType .

另請參閱 thresholdType () 和 Qt3DRender::QLevelOfDetail::ThresholdType .

[slot] void QLevelOfDetail:: setThresholds (const QVector < qreal > & thresholds )

Sets the range values in thresholds .

注意： setter 函數對於特性 thresholds .

另請參閱 thresholds () 和 Qt3DRender::QLevelOfDetail::thresholdType .