Renderer Class

class QQuickFramebufferObject::Renderer

This class was introduced in Qt 5.2.

• List of all members, including inherited members

Protected Functions

	Renderer()
virtual	~Renderer()
virtual QOpenGLFramebufferObject *	createFramebufferObject(const QSize &size)
QOpenGLFramebufferObject *	framebufferObject() const
void	invalidateFramebufferObject()
virtual void	render() = 0
virtual void	synchronize(QQuickFramebufferObject *item)
void	update()

Detailed Description

The QQuickFramebufferObject::Renderer class is used to implement the rendering logic of a QQuickFramebufferObject.

Member Function Documentation

[protected] Renderer::Renderer()

Constructs a new renderer.

This function is called during the scene graph sync phase when the GUI thread is blocked.

[virtual protected] Renderer::~Renderer()

The Renderer is automatically deleted when the scene graph resources for the QQuickFramebufferObject item is cleaned up.

This function is called on the rendering thread.

[virtual protected] QOpenGLFramebufferObject *Renderer::createFramebufferObject(const QSize &size)

This function is called when a new FBO is needed. This happens on the initial frame. If QQuickFramebufferObject::textureFollowsItemSize is set to true, it is called again every time the dimensions of the item changes.

The returned FBO can have any attachment. If the QOpenGLFramebufferObjectFormat indicates that the FBO should be multisampled, the internal implementation of the Renderer will allocate a second FBO and blit the multisampled FBO into the FBO used to display the texture.

[protected] QOpenGLFramebufferObject *Renderer::framebufferObject() const

Returns the framebuffer object currently being rendered to.

[protected] void Renderer::invalidateFramebufferObject()

Call this function during synchronize() to invalidate the current FBO. This will result in a new FBO being created with createFramebufferObject().

[pure virtual protected] void Renderer::render()

This function is called when the FBO should be rendered into. The framebuffer is bound at this point and the glViewport has been set up to match the FBO size.

The FBO will be automatically unbound after the function returns.

[virtual protected] void Renderer::synchronize(QQuickFramebufferObject *item)

This function is called as a result of QQuickFramebufferObject::update().

Use this function to update the renderer with changes that have occurred in the item. item is the item that instantiated this renderer. The function is called once before the FBO is created.

For instance, if the item has a color property which is controlled by QML, one should call QQuickFramebufferObject::update() and use synchronize() to copy the new color into the renderer so that it can be used to render the next frame.

This function is the only place when it is safe for the renderer and the item to read and write each others members.

[protected] void Renderer::update()

Call this function when the FBO should be rendered again.

This function can be called from render() to force the FBO to be rendered again before the next frame.