- Qt 6.8
- Qt Graphs
- C++ Classes
- QtGraphs
- Q3DScene
- Qt Graphs | Commercial or GPLv3

# Q3DScene Class

Q3DScene class provides description of the 3D scene being visualized. More...

Header: | `#include <Q3DScene>`
CMake: | `find_package(Qt6 REQUIRED COMPONENTS Graphs)` `target_link_libraries(mytarget PRIVATE Qt6::Graphs)`
qmake: | `QT += graphs`
In QML: | Scene3D

- List of all members, including inherited members
- Q3DScene is part of Qt Graphs C++ Classes for 3D.

## Properties

- devicePixelRatio : qreal
- graphPositionQuery : QPoint
- primarySubViewport : QRect
- secondarySubViewport : QRect

- secondarySubviewOnTop : bool
- selectionQueryPosition : QPoint
- slicingActive : bool
- viewport : const QRect

## Public Functions

| Q3DScene(QObject *parent = nullptr)
virtual | ~Q3DScene() override
qreal | devicePixelRatio() const
QPoint | graphPositionQuery() const
QPoint | invalidSelectionPoint() const
bool | isPointInPrimarySubView(QPoint point)
bool | isPointInSecondarySubView(QPoint point)
bool | isSecondarySubviewOnTop() const
bool | isSlicingActive() const
QRect | primarySubViewport() const
QRect | secondarySubViewport() const
QPoint | selectionQueryPosition() const
void | setDevicePixelRatio(qreal pixelRatio)
void | setGraphPositionQuery(QPoint point)
void | setPrimarySubViewport(QRect primarySubViewport)
void | setSecondarySubViewport(QRect secondarySubViewport)
void | setSecondarySubviewOnTop(bool isSecondaryOnTop)
void | setSelectionQueryPosition(QPoint point)
void | setSlicingActive(bool isSlicing)
QRect | viewport() const

## Signals

void | devicePixelRatioChanged(qreal pixelRatio)
void | graphPositionQueryChanged(QPoint position)
void | primarySubViewportChanged(QRect subViewport)
void | secondarySubViewportChanged(QRect subViewport)
void | secondarySubviewOnTopChanged(bool isSecondaryOnTop)
void | selectionQueryPositionChanged(QPoint position)
void | slicingActiveChanged(bool isSlicingActive)
void | viewportChanged(QRect viewport)

## Detailed Description

The 3D scene contains a single active camera and a single active light source. Visualized data is assumed to be at a fixed location.

The 3D scene also keeps track of the viewport in which graph rendering is done, the primary subviewport inside the viewport where the main 3D graphs view resides and the secondary subviewport where the 2D sliced view of the data resides. The subviewports are by default resized by the Q3DScene. To override the resize behavior you need to listen to both viewportChanged() and slicingActiveChanged() signals and recalculate the subviewports accordingly.

Also the scene has flag for tracking if the secondary 2D slicing view is currently active or not.

Note: Not all graphs support the secondary 2D slicing view.

## Property Documentation

### devicePixelRatio : qreal

This property holds the device pixel ratio that is used when mapping input coordinates to pixel coordinates.

Access functions:

qreal | devicePixelRatio() const
void | setDevicePixelRatio(qreal pixelRatio)

Notifier signal:

void | devicePixelRatioChanged(qreal pixelRatio)

### graphPositionQuery : QPoint

This property holds the coordinates for the user input that should be processed by the scene as a graph position query.

If this property is set to a value other than invalidSelectionPoint(), the graph tries to match a graph position to the specified coordinates within the primary viewport. After the rendering pass, this property is returned to its default state of invalidSelectionPoint(). The queried graph position can be read from the Q3DGraphsWidgetItem::queriedGraphPosition property after the next render pass.

There is no single correct 3D coordinate to match a particular screen position, so to be consistent, the queries are always done against the inner sides of an invisible box surrounding the graph.

Note: Bar graphs allow graph position queries only at the graph floor level.

Access functions:

QPoint | graphPositionQuery() const
void | setGraphPositionQuery(QPoint point)

Notifier signal:

void | graphPositionQueryChanged(QPoint position)

See also Q3DGraphsWidgetItem::queriedGraphPosition.

### primarySubViewport : QRect

This property holds the current subviewport rectangle inside the viewport where the primary view of the graphs is targeted.

If the primary sub viewport has not been explicitly set, it will be one fifth of viewport().

Note: Setting primarySubViewport larger than or outside of the viewport resizes the viewport accordingly.

Access functions:

QRect | primarySubViewport() const
void | setPrimarySubViewport(QRect primarySubViewport)

Notifier signal:

void | primarySubViewportChanged(QRect subViewport)

### secondarySubViewport : QRect

This property holds the secondary viewport rectangle inside the viewport.

The secondary viewport is used for drawing the 2D slice view in some graphs. If it has not been explicitly set, it will be equal to the size of the viewport.

Note: If the secondary sub viewport is larger than or outside of the viewport, the viewport is resized accordingly.

Access functions:

QRect | secondarySubViewport() const
void | setSecondarySubViewport(QRect secondarySubViewport)

Notifier signal:

void | secondarySubViewportChanged(QRect subViewport)

### secondarySubviewOnTop : bool

This property holds whether the 2D slicing view or the 3D view is drawn on top.

Access functions:

bool | isSecondarySubviewOnTop() const
void | setSecondarySubviewOnTop(bool isSecondaryOnTop)

Notifier signal:

void | secondarySubviewOnTopChanged(bool isSecondaryOnTop)

### selectionQueryPosition : QPoint

This property holds the coordinates for the user input that should be processed by the scene as a selection.

If this property is set to a value other than invalidSelectionPoint(), the graph tries to select a data item, axis label, or a custom item at the specified coordinates within the primary viewport. After the rendering pass, the property is returned to its default state of invalidSelectionPoint().

Access functions:

QPoint | selectionQueryPosition() const
void | setSelectionQueryPosition(QPoint point)

Notifier signal:

void | selectionQueryPositionChanged(QPoint position)

See also Q3DGraphsWidgetItem::selectedElement.

### slicingActive : bool

This property holds whether the 2D slicing view is currently active.

If `true`, Q3DGraphsWidgetItem::selectionMode must have either QtGraphs3D::SelectionFlag::Row or QtGraphs3D::SelectionFlag::Column set to a valid selection.

Note: Not all graphs support the 2D slicing view.

Access functions:

bool | isSlicingActive() const
void | setSlicingActive(bool isSlicing)

Notifier signal:

void | slicingActiveChanged(bool isSlicingActive)

### `[read-only]` viewport : const QRect

This property holds a read only property that contains the current viewport rectangle where all the 3D rendering is targeted.

Access functions:

QRect | viewport() const

Notifier signal:

void | viewportChanged(QRect viewport)

## Member Function Documentation

### `[explicit]` Q3DScene::Q3DScene(QObject *parent = nullptr)

Constructs a basic scene with one light and one camera in it. An optional parent parameter can be given and is then passed to QObject constructor.

### `[override virtual noexcept]` Q3DScene::~Q3DScene()

Destroys the 3D scene and all the objects contained within it.

### QPoint Q3DScene::invalidSelectionPoint() const

Returns a QPoint signifying an invalid selection position.

Note: Getter function for property invalidSelectionPoint.

### bool Q3DScene::isPointInPrimarySubView(QPoint point)

Returns whether the given point resides inside the primary subview or not. Returns `true` if the point is inside the primary subview.

Note: If subviews are superimposed, and the given point resides inside both, result is `true` only when the primary subview is on top.

### bool Q3DScene::isPointInSecondarySubView(QPoint point)

Returns whether the given point resides inside the secondary subview or not. Returns `true` if the point is inside the secondary subview.

Note: If subviews are superimposed, and the given point resides inside both, result is `true` only when the secondary subview is on top.