The QSGEngine class allows low level rendering of a scene graph. More...
| Header: | #include <QSGEngine> |
| qmake: | QT += quick |
| Since: | Qt 5.4 |
| Inherits: | QObject |
| enum | CreateTextureOption { TextureHasAlphaChannel, TextureOwnsGLTexture, TextureCanUseAtlas, TextureIsOpaque } |
| flags | CreateTextureOptions |
| QSGEngine(QObject *parent = nullptr) | |
| virtual | ~QSGEngine() override |
| QSGImageNode * | createImageNode() const |
| QSGNinePatchNode * | createNinePatchNode() const |
| QSGRectangleNode * | createRectangleNode() const |
| QSGAbstractRenderer * | createRenderer() const |
| QSGTexture * | createTextureFromId(uint id, const QSize &size, QSGEngine::CreateTextureOptions options) const |
| QSGTexture * | createTextureFromImage(const QImage &image, QSGEngine::CreateTextureOptions options) const |
| void | initialize(QOpenGLContext *context) |
| void | invalidate() |
| QSGRendererInterface * | rendererInterface() const |
The QSGEngine class allows low level rendering of a scene graph.
A QSGEngine can be used to render a tree of QSGNode directly on a QWindow or QOpenGLFramebufferObject without any integration with QML, QQuickWindow or QQuickItem and the convenience that they provide.
This means that you must handle event propagation, animation timing, and node lifetime yourself.
Note: This class is for very low level access to an independent scene graph. Most of the time you will instead want to subclass QQuickItem and insert your QSGNode in a normal QtQuick scene by overriding QQuickItem::updatePaintNode().
See also QSGAbstractRenderer.
The CreateTextureOption enums are used to customize how a texture is wrapped.
| Constant | Value | Description |
|---|---|---|
QSGEngine::TextureHasAlphaChannel |
0x0001 |
The texture has an alpha channel and should be drawn using blending. |
QSGEngine::TextureOwnsGLTexture |
0x0004 |
The texture object owns the texture id and will delete the GL texture when the texture object is deleted. |
QSGEngine::TextureCanUseAtlas |
0x0008 |
The image can be uploaded into a texture atlas. |
QSGEngine::TextureIsOpaque |
0x0010 |
The texture object is opaque. |
The CreateTextureOptions type is a typedef for QFlags<CreateTextureOption>. It stores an OR combination of CreateTextureOption values.
Constructs a new QSGEngine with its parent
[override virtual] QSGEngine::~QSGEngine()Destroys the engine
Creates a simple image node. When the scenegraph is not initialized, the return value is null.
This is cross-backend alternative to constructing a QSGSimpleTextureNode directly.
This function was introduced in Qt 5.8.
See also QSGImageNode.
Creates a nine patch node. When the scenegraph is not initialized, the return value is null.
This function was introduced in Qt 5.8.
Creates a simple rectangle node. When the scenegraph is not initialized, the return value is null.
This is cross-backend alternative to constructing a QSGSimpleRectNode directly.
This function was introduced in Qt 5.8.
See also QSGRectangleNode.
Returns a renderer that can be used to render a QSGNode tree
You call initialize() first with the QOpenGLContext that you want to use with this renderer. This will return a null renderer otherwise.
Creates a texture object that wraps the GL texture id uploaded with size
Valid options are TextureHasAlphaChannel and TextureOwnsGLTexture
The caller takes ownership of the texture object and the texture should only be used with this engine.
See also createTextureFromImage(), QSGSimpleTextureNode::setOwnsTexture(), and QQuickWindow::createTextureFromId().
Creates a texture using the data of image
Valid options are TextureCanUseAtlas and TextureIsOpaque.
The caller takes ownership of the texture and the texture should only be used with this engine.
See also createTextureFromId(), QSGSimpleTextureNode::setOwnsTexture(), and QQuickWindow::createTextureFromImage().
Initialize the engine with context.
Warning: You have to make sure that you call QOpenGLContext::makeCurrent() on context before calling this.
Invalidate the engine releasing its resources
You will have to call initialize() and createRenderer() if you want to use it again.
Returns the current renderer interface if there is one. Otherwise null is returned.
This function was introduced in Qt 5.8.
See also QSGRenderNode and QSGRendererInterface.
