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Fix up QQuickRenderControl class docs 

This was not updated together with the Qt 6 changes (the function docs
are up-to-date already), do it now.

Change-Id: I93c59df141a69d9943d1a3d88fe3a56fe6c096df
Reviewed-by: Eirik Aavitsland <eirik.aavitsland@qt.io>
This commit is contained in:
Laszlo Agocs 2020-06-12 13:23:37 +02:00
parent ee1101043f
commit 19f30c3463
1 changed files with 19 additions and 16 deletions
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35
src/quick/items/qquickrendercontrol.cpp
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@ -77,27 +77,30 @@ QT_BEGIN_NAMESPACE
QQuickWindow and QQuickView and their associated internal render loops render
the Qt Quick scene onto a native window. In some cases, for example when
integrating with 3rd party OpenGL renderers, it might be beneficial to get the
scene into a texture that can then be used in arbitrary ways by the external
rendering engine. QQuickRenderControl makes this possible in a hardware
accelerated manner, unlike the performance-wise limited alternative of using
QQuickWindow::grabWindow()
integrating with 3rd party OpenGL, Vulkan, Metal, or Direct 3D renderers, it
can be useful to get the scene into a texture that can then be used in
arbitrary ways by the external rendering engine. Such a mechanism is also
essential when integrating with a VR framework. QQuickRenderControl makes this
possible in a hardware accelerated manner, unlike the performance-wise limited
alternative of using QQuickWindow::grabWindow()
When using a QQuickRenderControl, the QQuickWindow does not have to be shown
or even created at all. This means there will not be an underlying native
window for it. Instead, the QQuickWindow instance is associated with the
render control, using the overload of the QQuickWindow constructor, and an
OpenGL framebuffer object by calling QQuickWindow::setRenderTarget().
render control, using the overload of the QQuickWindow constructor, and a
texture or image object specified via QQuickWindow::setRenderTarget().
Management of the context and framebuffer object is up to the application. The
context that will be used by Qt Quick must be created before calling
initialize(). The creation of the framebuffer object can be deferred, see
below. Qt 5.4 introduces the ability for QOpenGLContext to adopt existing
native contexts. Together with QQuickRenderControl this makes it possible to
create a QOpenGLContext that shares with an external rendering engine's
existing context. This new QOpenGLContext can then be used to render the Qt
Quick scene into a texture that is accessible by the other engine's context
too.
Management of the graphics devices, contexts, image and texture objects is up
to the application. The device or context that will be used by Qt Quick must
be created before calling initialize(). The creation of the the texture object
can be deferred, see below. Qt 5.4 introduces the ability for QOpenGLContext
to adopt existing native contexts. Together with QQuickRenderControl this
makes it possible to create a QOpenGLContext that shares with an external
rendering engine's existing context. This new QOpenGLContext can then be used
to render the Qt Quick scene into a texture that is accessible by the other
engine's context too. For Vulkan, Metal, and Direct 3D there are no
Qt-provided wrappers for device objects, so existing ones can be passed as-is
via QQuickWindow::setGraphicsDevice().
Loading and instantiation of the QML components happen by using a
QQmlEngine. Once the root object is created, it will need to be parented to