QQuickFramebufferObject

The QQuickFramebufferObject class is a convenience class for integrating OpenGL rendering using a framebuffer object (FBO) with Qt Quick. More

Inheritance diagram of PySide2.QtQuick.QQuickFramebufferObject

Synopsis

Functions

Virtual functions

Signals

Detailed Description

On most platforms, the rendering will occur on a dedicated thread . For this reason, the QQuickFramebufferObject class enforces a strict separation between the item implementation and the FBO rendering. All item logic, such as properties and UI-related helper functions needed by QML should be located in a QQuickFramebufferObject class subclass. Everything that relates to rendering must be located in the Renderer class.

Warning

This class is only functional when Qt Quick is rendering via OpenGL, either directly or through the RHI-based rendering path . It is not compatible with other RHI backends, such as, Vulkan or Metal.

To avoid race conditions and read/write issues from two threads it is important that the renderer and the item never read or write shared variables. Communication between the item and the renderer should primarily happen via the synchronize() function. This function will be called on the render thread while the GUI thread is blocked.

Using queued connections or events for communication between item and renderer is also possible.

Both the Renderer and the FBO are memory managed internally.

To render into the FBO, the user should subclass the Renderer class and reimplement its render() function. The Renderer subclass is returned from createRenderer() .

The size of the FBO will by default adapt to the size of the item. If a fixed size is preferred, set textureFollowsItemSize to false and return a texture of your choosing from createFramebufferObject() .

Starting Qt 5.4, the QQuickFramebufferObject class is a texture provider and can be used directly in ShaderEffects and other classes that consume texture providers.

See also

Scene Graph - Rendering FBOs Scene Graph and Rendering

class QQuickFramebufferObject([parent=None])
param parent

QQuickItem

Constructs a new QQuickFramebufferObject with parent parent .

PySide2.QtQuick.QQuickFramebufferObject.createRenderer()
Return type

Renderer

Reimplement this function to create a renderer used to render into the FBO.

This function will be called on the rendering thread while the GUI thread is blocked.

PySide2.QtQuick.QQuickFramebufferObject.mirrorVertically()
Return type

bool

PySide2.QtQuick.QQuickFramebufferObject.mirrorVerticallyChanged(arg__1)
Parameters

arg__1bool

PySide2.QtQuick.QQuickFramebufferObject.setMirrorVertically(enable)
Parameters

enablebool

PySide2.QtQuick.QQuickFramebufferObject.setTextureFollowsItemSize(follows)
Parameters

followsbool

PySide2.QtQuick.QQuickFramebufferObject.textureFollowsItemSize()
Return type

bool

PySide2.QtQuick.QQuickFramebufferObject.textureFollowsItemSizeChanged(arg__1)
Parameters

arg__1bool