QQuickFramebufferObject

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

Synopsis

Functions

• def mirrorVertically ()

• def mirrorVerticallyChanged (arg__1)

• def setMirrorVertically (enable)

• def setTextureFollowsItemSize (follows)

• def textureFollowsItemSize ()

• def textureFollowsItemSizeChanged (arg__1)

Virtual functions

• def createRenderer ()

Detailed Description

Warning

This class is only functional when Qt Quick is rendering via OpenGL. It is not compatible with other graphics APIs, such as Vulkan or Metal. It should be treated as a legacy class that is only present in order to enable Qt 5 applications to function without source compatibility breaks as long as they tie themselves to OpenGL.

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.

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 PySide6.QtQuick.QQuickFramebufferObject([parent=None])

Parameters

parent – PySide6.QtQuick.QQuickItem

Constructs a new QQuickFramebufferObject with parent parent.

PySide6.QtQuick.QQuickFramebufferObject.createRenderer()

Return type

PySide6.QtQuick.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.

PySide6.QtQuick.QQuickFramebufferObject.mirrorVertically()

Return type

bool

See also

setMirrorVertically()

PySide6.QtQuick.QQuickFramebufferObject.mirrorVerticallyChanged(arg__1)

Parameters

arg__1 – bool

PySide6.QtQuick.QQuickFramebufferObject.setMirrorVertically(enable)

Parameters

enable – bool

See also

mirrorVertically()

PySide6.QtQuick.QQuickFramebufferObject.setTextureFollowsItemSize(follows)

Parameters

follows – bool

See also

textureFollowsItemSize()

PySide6.QtQuick.QQuickFramebufferObject.textureFollowsItemSize()

Return type

bool

See also

setTextureFollowsItemSize()

PySide6.QtQuick.QQuickFramebufferObject.textureFollowsItemSizeChanged(arg__1)

Parameters

arg__1 – bool