Remove QSGEngine and move QSGAbstractRenderer back to private

QSGEngine goes away. Same for the associated example, which is the only
place this is used anywhere in Qt.

As a consequence, the renderer base class can be moved back to private:
there is no use for it to be public anymore, since that made sense only
in combination with QSGEngine. With the RHI-based rendering path driving
a renderer directly is more complicated than before so it is not
reasonable to allow the QSGEngine-style access anymore.

Instead, one has QQuickRenderControl, which allows redirecting and
manually driving the rendering of a QQuickWindow, thus providing an
alternative to the legacy QSGEngine approach.

Task-number: QTBUG-78596
Change-Id: If57c6b657b2053da1c4e545e517026382a71d998
Reviewed-by: Andy Nichols <andy.nichols@qt.io>

10 files changed, 93 insertions, 554 deletions

diff --git a/src/quick/scenegraph/coreapi/qsgabstractrenderer.cpp b/src/quick/scenegraph/coreapi/qsgabstractrenderer.cpp
index 62ed342244..502ee27e27 100644
--- a/src/quick/scenegraph/coreapi/qsgabstractrenderer.cpp
+++ b/src/quick/scenegraph/coreapi/qsgabstractrenderer.cpp
@@ -37,26 +37,16 @@
 **
 ****************************************************************************/
 
-#include "qsgabstractrenderer_p.h"
+#include "qsgabstractrenderer_p_p.h"
 
 QT_BEGIN_NAMESPACE
 
 /*!
     \class QSGAbstractRenderer
-    \brief QSGAbstractRenderer gives access to the scene graph nodes and rendering of a QSGEngine.
+    \brief QSGAbstractRenderer gives access to the scene graph nodes and rendering.
     \inmodule QtQuick
     \since 5.4
-
-    A QSGAbstractRenderer created by a QSGEngine allows you to set your QSGNode
-    tree through setRootNode() and control the rendering viewport through
-    setDeviceRect(), setViewportRect() and setProjectionMatrixToRect().
-    You can finally trigger the rendering to the desired framebuffer through
-    renderScene().
-
-    The QSGAbstractRenderer is only available when used with a QSGEngine
-    and isn't exposed when used internally by QQuickWindow.
-
-    \sa QSGEngine, QSGNode
+    \internal
  */
 
 /*!
@@ -387,5 +377,3 @@ QSGAbstractRenderer::ClearMode QSGAbstractRenderer::clearMode() const
  */
 
 QT_END_NAMESPACE
-
-#include "moc_qsgabstractrenderer.cpp"
diff --git a/src/quick/scenegraph/coreapi/qsgabstractrenderer.h b/src/quick/scenegraph/coreapi/qsgabstractrenderer.h
deleted file mode 100644
index 1594352dab..0000000000
--- a/src/quick/scenegraph/coreapi/qsgabstractrenderer.h
+++ /dev/null
@@ -1,116 +0,0 @@
-/****************************************************************************
-**
-** Copyright (C) 2016 The Qt Company Ltd.
-** Contact: https://www.qt.io/licensing/
-**
-** This file is part of the QtQuick module of the Qt Toolkit.
-**
-** $QT_BEGIN_LICENSE:LGPL$
-** Commercial License Usage
-** Licensees holding valid commercial Qt licenses may use this file in
-** accordance with the commercial license agreement provided with the
-** Software or, alternatively, in accordance with the terms contained in
-** a written agreement between you and The Qt Company. For licensing terms
-** and conditions see https://www.qt.io/terms-conditions. For further
-** information use the contact form at https://www.qt.io/contact-us.
-**
-** GNU Lesser General Public License Usage
-** Alternatively, this file may be used under the terms of the GNU Lesser
-** General Public License version 3 as published by the Free Software
-** Foundation and appearing in the file LICENSE.LGPL3 included in the
-** packaging of this file. Please review the following information to
-** ensure the GNU Lesser General Public License version 3 requirements
-** will be met: https://www.gnu.org/licenses/lgpl-3.0.html.
-**
-** GNU General Public License Usage
-** Alternatively, this file may be used under the terms of the GNU
-** General Public License version 2.0 or (at your option) the GNU General
-** Public license version 3 or any later version approved by the KDE Free
-** Qt Foundation. The licenses are as published by the Free Software
-** Foundation and appearing in the file LICENSE.GPL2 and LICENSE.GPL3
-** included in the packaging of this file. Please review the following
-** information to ensure the GNU General Public License requirements will
-** be met: https://www.gnu.org/licenses/gpl-2.0.html and
-** https://www.gnu.org/licenses/gpl-3.0.html.
-**
-** $QT_END_LICENSE$
-**
-****************************************************************************/
-
-#ifndef QSGABSTRACTRENDERER_H
-#define QSGABSTRACTRENDERER_H
-
-#include <QtQuick/qsgnode.h>
-
-#ifndef GLuint
-#define GLuint uint
-#endif
-
-QT_BEGIN_NAMESPACE
-
-class QSGAbstractRendererPrivate;
-
-class Q_QUICK_EXPORT QSGAbstractRenderer : public QObject
-{
-    Q_OBJECT
-public:
-    enum ClearModeBit
-    {
-        ClearColorBuffer    = 0x0001,
-        ClearDepthBuffer    = 0x0002,
-        ClearStencilBuffer  = 0x0004
-    };
-    Q_DECLARE_FLAGS(ClearMode, ClearModeBit)
-    Q_FLAG(ClearMode)
-
-    enum MatrixTransformFlag
-    {
-        MatrixTransformFlipY = 0x01
-    };
-    Q_DECLARE_FLAGS(MatrixTransformFlags, MatrixTransformFlag)
-    Q_FLAG(MatrixTransformFlags)
-
-    ~QSGAbstractRenderer() override;
-
-    void setRootNode(QSGRootNode *node);
-    QSGRootNode *rootNode() const;
-    void setDeviceRect(const QRect &rect);
-    inline void setDeviceRect(const QSize &size) { setDeviceRect(QRect(QPoint(), size)); }
-    QRect deviceRect() const;
-
-    void setViewportRect(const QRect &rect);
-    inline void setViewportRect(const QSize &size) { setViewportRect(QRect(QPoint(), size)); }
-    QRect viewportRect() const;
-
-    void setProjectionMatrixToRect(const QRectF &rect);
-    void setProjectionMatrixToRect(const QRectF &rect, MatrixTransformFlags flags);
-    void setProjectionMatrix(const QMatrix4x4 &matrix);
-    void setProjectionMatrixWithNativeNDC(const QMatrix4x4 &matrix);
-    QMatrix4x4 projectionMatrix() const;
-    QMatrix4x4 projectionMatrixWithNativeNDC() const;
-
-    void setClearColor(const QColor &color);
-    QColor clearColor() const;
-
-    void setClearMode(ClearMode mode);
-    ClearMode clearMode() const;
-
-    virtual void renderScene(GLuint fboId = 0) = 0;
-
-Q_SIGNALS:
-    void sceneGraphChanged();
-
-protected:
-    explicit QSGAbstractRenderer(QObject *parent = nullptr);
-    virtual void nodeChanged(QSGNode *node, QSGNode::DirtyState state) = 0;
-
-private:
-    Q_DECLARE_PRIVATE(QSGAbstractRenderer)
-    friend class QSGRootNode;
-};
-
-Q_DECLARE_OPERATORS_FOR_FLAGS(QSGAbstractRenderer::ClearMode)
-
-QT_END_NAMESPACE
-
-#endif
diff --git a/src/quick/scenegraph/coreapi/qsgabstractrenderer_p.h b/src/quick/scenegraph/coreapi/qsgabstractrenderer_p.h
index bbc4289b2c..5d48f18310 100644
--- a/src/quick/scenegraph/coreapi/qsgabstractrenderer_p.h
+++ b/src/quick/scenegraph/coreapi/qsgabstractrenderer_p.h
@@ -51,37 +51,78 @@
 // We mean it.
 //
 
-#include "qsgabstractrenderer.h"
-
-#include "qsgnode.h"
-#include <qcolor.h>
-
-#include <QtCore/private/qobject_p.h>
 #include <QtQuick/private/qtquickglobal_p.h>
+#include <QtQuick/qsgnode.h>
+
+#ifndef GLuint
+#define GLuint uint
+#endif
 
 QT_BEGIN_NAMESPACE
 
-class Q_QUICK_PRIVATE_EXPORT QSGAbstractRendererPrivate : public QObjectPrivate
+class QSGAbstractRendererPrivate;
+
+class Q_QUICK_PRIVATE_EXPORT QSGAbstractRenderer : public QObject
 {
-    Q_DECLARE_PUBLIC(QSGAbstractRenderer)
+    Q_OBJECT
 public:
-    static const QSGAbstractRendererPrivate *get(const QSGAbstractRenderer *q) { return q->d_func(); }
+    enum ClearModeBit
+    {
+        ClearColorBuffer    = 0x0001,
+        ClearDepthBuffer    = 0x0002,
+        ClearStencilBuffer  = 0x0004
+    };
+    Q_DECLARE_FLAGS(ClearMode, ClearModeBit)
+    Q_FLAG(ClearMode)
+
+    enum MatrixTransformFlag
+    {
+        MatrixTransformFlipY = 0x01
+    };
+    Q_DECLARE_FLAGS(MatrixTransformFlags, MatrixTransformFlag)
+    Q_FLAG(MatrixTransformFlags)
+
+    ~QSGAbstractRenderer() override;
 
-    QSGAbstractRendererPrivate();
-    void updateProjectionMatrix();
+    void setRootNode(QSGRootNode *node);
+    QSGRootNode *rootNode() const;
+    void setDeviceRect(const QRect &rect);
+    inline void setDeviceRect(const QSize &size) { setDeviceRect(QRect(QPoint(), size)); }
+    QRect deviceRect() const;
 
-    QSGRootNode *m_root_node;
-    QColor m_clear_color;
-    QSGAbstractRenderer::ClearMode m_clear_mode;
+    void setViewportRect(const QRect &rect);
+    inline void setViewportRect(const QSize &size) { setViewportRect(QRect(QPoint(), size)); }
+    QRect viewportRect() const;
 
-    QRect m_device_rect;
-    QRect m_viewport_rect;
+    void setProjectionMatrixToRect(const QRectF &rect);
+    void setProjectionMatrixToRect(const QRectF &rect, MatrixTransformFlags flags);
+    void setProjectionMatrix(const QMatrix4x4 &matrix);
+    void setProjectionMatrixWithNativeNDC(const QMatrix4x4 &matrix);
+    QMatrix4x4 projectionMatrix() const;
+    QMatrix4x4 projectionMatrixWithNativeNDC() const;
 
-    QMatrix4x4 m_projection_matrix;
-    QMatrix4x4 m_projection_matrix_native_ndc;
-    uint m_mirrored : 1;
+    void setClearColor(const QColor &color);
+    QColor clearColor() const;
+
+    void setClearMode(ClearMode mode);
+    ClearMode clearMode() const;
+
+    virtual void renderScene(GLuint fboId = 0) = 0;
+
+Q_SIGNALS:
+    void sceneGraphChanged();
+
+protected:
+    explicit QSGAbstractRenderer(QObject *parent = nullptr);
+    virtual void nodeChanged(QSGNode *node, QSGNode::DirtyState state) = 0;
+
+private:
+    Q_DECLARE_PRIVATE(QSGAbstractRenderer)
+    friend class QSGRootNode;
 };
 
+Q_DECLARE_OPERATORS_FOR_FLAGS(QSGAbstractRenderer::ClearMode)
+
 QT_END_NAMESPACE
 
 #endif
diff --git a/src/quick/scenegraph/util/qsgengine_p.h b/src/quick/scenegraph/coreapi/qsgabstractrenderer_p_p.h
index c5b5c695bd..42e9acb437 100644
--- a/src/quick/scenegraph/util/qsgengine_p.h
+++ b/src/quick/scenegraph/coreapi/qsgabstractrenderer_p_p.h
@@ -37,8 +37,8 @@
 **
 ****************************************************************************/
 
-#ifndef QSGENGINE_P_H
-#define QSGENGINE_P_H
+#ifndef QSGABSTRACTRENDERER_P_P_H
+#define QSGABSTRACTRENDERER_P_P_H
 
 //
 //  W A R N I N G
@@ -51,25 +51,37 @@
 // We mean it.
 //
 
-#include "qsgengine.h"
-#include <private/qobject_p.h>
+#include "qsgabstractrenderer_p.h"
 
-QT_BEGIN_NAMESPACE
+#include "qsgnode.h"
+#include <qcolor.h>
+
+#include <QtCore/private/qobject_p.h>
+#include <QtQuick/private/qtquickglobal_p.h>
 
-class QSGContext;
-class QSGRenderContext;
+QT_BEGIN_NAMESPACE
 
-class QSGEnginePrivate : public QObjectPrivate
+class Q_QUICK_PRIVATE_EXPORT QSGAbstractRendererPrivate : public QObjectPrivate
 {
-    Q_DECLARE_PUBLIC(QSGEngine)
+    Q_DECLARE_PUBLIC(QSGAbstractRenderer)
 public:
-    static QSGEnginePrivate *get(QSGEngine *engine) { return engine->d_func(); }
-    QSGEnginePrivate();
+    static const QSGAbstractRendererPrivate *get(const QSGAbstractRenderer *q) { return q->d_func(); }
+
+    QSGAbstractRendererPrivate();
+    void updateProjectionMatrix();
+
+    QSGRootNode *m_root_node;
+    QColor m_clear_color;
+    QSGAbstractRenderer::ClearMode m_clear_mode;
+
+    QRect m_device_rect;
+    QRect m_viewport_rect;
 
-    QScopedPointer<QSGContext> sgContext;
-    QScopedPointer<QSGRenderContext> sgRenderContext;
+    QMatrix4x4 m_projection_matrix;
+    QMatrix4x4 m_projection_matrix_native_ndc;
+    uint m_mirrored : 1;
 };
 
 QT_END_NAMESPACE
 
-#endif // QSGENGINE_P_H
+#endif
diff --git a/src/quick/scenegraph/coreapi/qsgrenderer_p.h b/src/quick/scenegraph/coreapi/qsgrenderer_p.h
index c4ed0072f6..b25ecb0ae6 100644
--- a/src/quick/scenegraph/coreapi/qsgrenderer_p.h
+++ b/src/quick/scenegraph/coreapi/qsgrenderer_p.h
@@ -51,8 +51,7 @@
 // We mean it.
 //
 
-#include "qsgabstractrenderer.h"
-#include "qsgabstractrenderer_p.h"
+#include "qsgabstractrenderer_p_p.h"
 #include "qsgnode.h"
 #include "qsgmaterial.h"
 
diff --git a/src/quick/scenegraph/scenegraph.pri b/src/quick/scenegraph/scenegraph.pri
index b12f57d8ef..56dda508c6 100644
--- a/src/quick/scenegraph/scenegraph.pri
+++ b/src/quick/scenegraph/scenegraph.pri
@@ -12,8 +12,8 @@ HEADERS += \
     $$PWD/coreapi/qsgnode.h \
     $$PWD/coreapi/qsgnode_p.h \
     $$PWD/coreapi/qsgnodeupdater_p.h \
-    $$PWD/coreapi/qsgabstractrenderer.h \
     $$PWD/coreapi/qsgabstractrenderer_p.h \
+    $$PWD/coreapi/qsgabstractrenderer_p_p.h \
     $$PWD/coreapi/qsgrenderer_p.h \
     $$PWD/coreapi/qsgrendernode.h \
     $$PWD/coreapi/qsgrendernode_p.h \
@@ -50,8 +50,6 @@ qtConfig(opengl(es1|es2)?) {
 # Util API
 HEADERS += \
     $$PWD/util/qsgareaallocator_p.h \
-    $$PWD/util/qsgengine.h \
-    $$PWD/util/qsgengine_p.h \
     $$PWD/util/qsgplaintexture_p.h \
     $$PWD/util/qsgsimplerectnode.h \
     $$PWD/util/qsgsimpletexturenode.h \
@@ -67,7 +65,6 @@ HEADERS += \
 
 SOURCES += \
     $$PWD/util/qsgareaallocator.cpp \
-    $$PWD/util/qsgengine.cpp \
     $$PWD/util/qsgplaintexture.cpp \
     $$PWD/util/qsgsimplerectnode.cpp \
     $$PWD/util/qsgsimpletexturenode.cpp \
diff --git a/src/quick/scenegraph/util/qsgengine.cpp b/src/quick/scenegraph/util/qsgengine.cpp
deleted file mode 100644
index 13c97e8615..0000000000
--- a/src/quick/scenegraph/util/qsgengine.cpp
+++ /dev/null
@@ -1,290 +0,0 @@
-/****************************************************************************
-**
-** Copyright (C) 2016 The Qt Company Ltd.
-** Contact: https://www.qt.io/licensing/
-**
-** This file is part of the QtQuick module of the Qt Toolkit.
-**
-** $QT_BEGIN_LICENSE:LGPL$
-** Commercial License Usage
-** Licensees holding valid commercial Qt licenses may use this file in
-** accordance with the commercial license agreement provided with the
-** Software or, alternatively, in accordance with the terms contained in
-** a written agreement between you and The Qt Company. For licensing terms
-** and conditions see https://www.qt.io/terms-conditions. For further
-** information use the contact form at https://www.qt.io/contact-us.
-**
-** GNU Lesser General Public License Usage
-** Alternatively, this file may be used under the terms of the GNU Lesser
-** General Public License version 3 as published by the Free Software
-** Foundation and appearing in the file LICENSE.LGPL3 included in the
-** packaging of this file. Please review the following information to
-** ensure the GNU Lesser General Public License version 3 requirements
-** will be met: https://www.gnu.org/licenses/lgpl-3.0.html.
-**
-** GNU General Public License Usage
-** Alternatively, this file may be used under the terms of the GNU
-** General Public License version 2.0 or (at your option) the GNU General
-** Public license version 3 or any later version approved by the KDE Free
-** Qt Foundation. The licenses are as published by the Free Software
-** Foundation and appearing in the file LICENSE.GPL2 and LICENSE.GPL3
-** included in the packaging of this file. Please review the following
-** information to ensure the GNU General Public License requirements will
-** be met: https://www.gnu.org/licenses/gpl-2.0.html and
-** https://www.gnu.org/licenses/gpl-3.0.html.
-**
-** $QT_END_LICENSE$
-**
-****************************************************************************/
-
-#include "qsgengine_p.h"
-
-#include <QtQuick/qsgtexture.h>
-#include <private/qsgcontext_p.h>
-#include <private/qsgrenderer_p.h>
-#include <private/qsgplaintexture_p.h>
-
-#if QT_CONFIG(opengl)
-# include <QOpenGLContext>
-# include <private/qsgdefaultrendercontext_p.h>
-#endif
-
-QT_BEGIN_NAMESPACE
-
-
-/*!
-    \class QSGEngine
-    \brief The QSGEngine class allows low level rendering of a scene graph.
-    \inmodule QtQuick
-    \since 5.4
-
-    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().
-
-    \warning This class is only suitable when working directly with OpenGL. It
-    is not compatible with the \l{Scene Graph Adaptations}{RHI-based rendering
-    path}.
-
-    \sa QSGAbstractRenderer
- */
-
-/*!
-    \enum QSGEngine::CreateTextureOption
-
-    The CreateTextureOption enums are used to customize how a texture is wrapped.
-
-    \value TextureHasAlphaChannel The texture has an alpha channel and should
-    be drawn using blending.
-
-    \value TextureOwnsGLTexture The texture object owns the texture id and
-    will delete the GL texture when the texture object is deleted.
-
-    \value TextureCanUseAtlas The image can be uploaded into a texture atlas.
-
-    \value TextureIsOpaque The texture object is opaque.
- */
-
-QSGEnginePrivate::QSGEnginePrivate()
-    : sgContext(QSGContext::createDefaultContext())
-    , sgRenderContext(sgContext.data()->createRenderContext())
-{
-}
-
-/*!
-    Constructs a new QSGEngine with its \a parent
- */
-QSGEngine::QSGEngine(QObject *parent)
-    : QObject(*(new QSGEnginePrivate), parent)
-{
-}
-
-/*!
-    Destroys the engine
- */
-QSGEngine::~QSGEngine()
-{
-}
-
-/*!
-    Initialize the engine with \a context.
-
-    \warning You have to make sure that you call
-    QOpenGLContext::makeCurrent() on \a context before calling this.
- */
-void QSGEngine::initialize(QOpenGLContext *context)
-{
-    Q_D(QSGEngine);
-#if QT_CONFIG(opengl)
-    if (context && QOpenGLContext::currentContext() != context) {
-        qWarning("WARNING: The context must be current before calling QSGEngine::initialize.");
-        return;
-    }
-#endif
-    if (d->sgRenderContext && !d->sgRenderContext->isValid()) {
-        d->sgRenderContext->setAttachToGraphicsContext(false);
-#if QT_CONFIG(opengl)
-        QSGDefaultRenderContext *rc = qobject_cast<QSGDefaultRenderContext *>(d->sgRenderContext.data());
-        if (rc) {
-            QSGDefaultRenderContext::InitParams params;
-            params.sampleCount = qMax(1, context->format().samples());
-            params.openGLContext = context;
-            // leave the size hint and surface unset, we do not know, that's fine
-            rc->initialize(&params);
-        } else {
-            d->sgRenderContext->initialize(nullptr);
-        }
-#else
-        d->sgRenderContext->initialize(nullptr);
-#endif
-#if QT_CONFIG(opengl)
-        if (context)
-            connect(context, &QOpenGLContext::aboutToBeDestroyed, this, &QSGEngine::invalidate);
-#endif
-    }
-
-#if !QT_CONFIG(opengl)
-    Q_UNUSED(context);
-#endif
-}
-
-/*!
-    Invalidate the engine releasing its resources
-
-    You will have to call initialize() and createRenderer() if you
-    want to use it again.
- */
-void QSGEngine::invalidate()
-{
-    Q_D(QSGEngine);
-    d->sgRenderContext->invalidate();
-}
-
-/*!
-    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.
- */
-QSGAbstractRenderer *QSGEngine::createRenderer() const
-{
-    Q_D(const QSGEngine);
-    if (!d->sgRenderContext->isValid())
-        return nullptr;
-
-    QSGRenderer *renderer = d->sgRenderContext->createRenderer();
-    renderer->setCustomRenderMode(qgetenv("QSG_VISUALIZE"));
-    return renderer;
-}
-
-/*!
-    Creates a texture using the data of \a image
-
-    Valid \a options are TextureCanUseAtlas and TextureIsOpaque.
-
-    The caller takes ownership of the texture and the
-    texture should only be used with this engine.
-
-    \sa createTextureFromId(), QSGSimpleTextureNode::setOwnsTexture(), QQuickWindow::createTextureFromImage()
- */
-QSGTexture *QSGEngine::createTextureFromImage(const QImage &image, CreateTextureOptions options) const
-{
-    Q_D(const QSGEngine);
-     if (!d->sgRenderContext->isValid())
-         return nullptr;
-    uint flags = 0;
-    if (options & TextureCanUseAtlas)     flags |= QSGRenderContext::CreateTexture_Atlas;
-    if (!(options & TextureIsOpaque))     flags |= QSGRenderContext::CreateTexture_Alpha;
-    return d->sgRenderContext->createTexture(image, flags);
-}
-
-/*!
-    Creates a texture object that wraps the GL texture \a id uploaded with \a size
-
-    Valid \a options are TextureHasAlphaChannel and TextureOwnsGLTexture
-
-    The caller takes ownership of the texture object and the
-    texture should only be used with this engine.
-
-    \sa createTextureFromImage(), QSGSimpleTextureNode::setOwnsTexture(), QQuickWindow::createTextureFromId()
- */
-QSGTexture *QSGEngine::createTextureFromId(uint id, const QSize &size, CreateTextureOptions options) const
-{
-    Q_D(const QSGEngine);
-    if (d->sgRenderContext->isValid()) {
-        QSGPlainTexture *texture = new QSGPlainTexture();
-        texture->setTextureId(id);
-        texture->setHasAlphaChannel(options & TextureHasAlphaChannel);
-        texture->setOwnsTexture(options & TextureOwnsGLTexture);
-        texture->setTextureSize(size);
-        return texture;
-    }
-    return nullptr;
-}
-
-/*!
-    Returns the current renderer interface if there is one. Otherwise null is returned.
-
-    \sa QSGRenderNode, QSGRendererInterface
-    \since 5.8
- */
-QSGRendererInterface *QSGEngine::rendererInterface() const
-{
-    Q_D(const QSGEngine);
-    return d->sgRenderContext->isValid()
-            ? d->sgRenderContext->sceneGraphContext()->rendererInterface(d->sgRenderContext.data())
-            : nullptr;
-}
-
-/*!
-    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.
-
-    \since 5.8
-    \sa QSGRectangleNode
- */
-QSGRectangleNode *QSGEngine::createRectangleNode() const
-{
-    Q_D(const QSGEngine);
-    return d->sgRenderContext->isValid() ? d->sgRenderContext->sceneGraphContext()->createRectangleNode() : nullptr;
-}
-
-/*!
-    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.
-
-    \since 5.8
-    \sa QSGImageNode
- */
-
-QSGImageNode *QSGEngine::createImageNode() const
-{
-    Q_D(const QSGEngine);
-    return d->sgRenderContext->isValid() ? d->sgRenderContext->sceneGraphContext()->createImageNode() : nullptr;
-}
-
-/*!
-    Creates a nine patch node. When the scenegraph is not initialized, the return value is null.
-
-    \since 5.8
- */
-
-QSGNinePatchNode *QSGEngine::createNinePatchNode() const
-{
-    Q_D(const QSGEngine);
-    return d->sgRenderContext->isValid() ? d->sgRenderContext->sceneGraphContext()->createNinePatchNode() : nullptr;
-}
-
-QT_END_NAMESPACE
-
-#include "moc_qsgengine.cpp"
diff --git a/src/quick/scenegraph/util/qsgengine.h b/src/quick/scenegraph/util/qsgengine.h
deleted file mode 100644
index c5a59b47e7..0000000000
--- a/src/quick/scenegraph/util/qsgengine.h
+++ /dev/null
@@ -1,90 +0,0 @@
-/****************************************************************************
-**
-** Copyright (C) 2016 The Qt Company Ltd.
-** Contact: https://www.qt.io/licensing/
-**
-** This file is part of the QtQuick module of the Qt Toolkit.
-**
-** $QT_BEGIN_LICENSE:LGPL$
-** Commercial License Usage
-** Licensees holding valid commercial Qt licenses may use this file in
-** accordance with the commercial license agreement provided with the
-** Software or, alternatively, in accordance with the terms contained in
-** a written agreement between you and The Qt Company. For licensing terms
-** and conditions see https://www.qt.io/terms-conditions. For further
-** information use the contact form at https://www.qt.io/contact-us.
-**
-** GNU Lesser General Public License Usage
-** Alternatively, this file may be used under the terms of the GNU Lesser
-** General Public License version 3 as published by the Free Software
-** Foundation and appearing in the file LICENSE.LGPL3 included in the
-** packaging of this file. Please review the following information to
-** ensure the GNU Lesser General Public License version 3 requirements
-** will be met: https://www.gnu.org/licenses/lgpl-3.0.html.
-**
-** GNU General Public License Usage
-** Alternatively, this file may be used under the terms of the GNU
-** General Public License version 2.0 or (at your option) the GNU General
-** Public license version 3 or any later version approved by the KDE Free
-** Qt Foundation. The licenses are as published by the Free Software
-** Foundation and appearing in the file LICENSE.GPL2 and LICENSE.GPL3
-** included in the packaging of this file. Please review the following
-** information to ensure the GNU General Public License requirements will
-** be met: https://www.gnu.org/licenses/gpl-2.0.html and
-** https://www.gnu.org/licenses/gpl-3.0.html.
-**
-** $QT_END_LICENSE$
-**
-****************************************************************************/
-
-#ifndef QSGENGINE_H
-#define QSGENGINE_H
-
-#include <QtCore/QObject>
-#include <QtQuick/qtquickglobal.h>
-
-QT_BEGIN_NAMESPACE
-
-class QOpenGLContext;
-class QSGAbstractRenderer;
-class QSGEnginePrivate;
-class QSGTexture;
-class QSGRendererInterface;
-class QSGRectangleNode;
-class QSGImageNode;
-class QSGNinePatchNode;
-
-// ### Qt 6: Remove or redesign.
-
-class Q_QUICK_EXPORT QSGEngine : public QObject
-{
-    Q_OBJECT
-    Q_DECLARE_PRIVATE(QSGEngine)
-public:
-    enum CreateTextureOption {
-        TextureHasAlphaChannel  = 0x0001,
-        TextureOwnsGLTexture    = 0x0004,
-        TextureCanUseAtlas      = 0x0008,
-        TextureIsOpaque         = 0x0010
-    };
-    Q_DECLARE_FLAGS(CreateTextureOptions, CreateTextureOption)
-    Q_FLAG(CreateTextureOptions)
-
-    explicit QSGEngine(QObject *parent = nullptr);
-    ~QSGEngine() override;
-
-    void initialize(QOpenGLContext *context);
-    void invalidate();
-
-    QSGAbstractRenderer *createRenderer() const;
-    QSGTexture *createTextureFromImage(const QImage &image, CreateTextureOptions options = CreateTextureOption()) const;
-    QSGTexture *createTextureFromId(uint id, const QSize &size, CreateTextureOptions options = CreateTextureOption()) const;
-    QSGRendererInterface *rendererInterface() const;
-    QSGRectangleNode *createRectangleNode() const;
-    QSGImageNode *createImageNode() const;
-    QSGNinePatchNode *createNinePatchNode() const;
-};
-
-QT_END_NAMESPACE
-
-#endif // QSGENGINE_H
diff --git a/src/quick/scenegraph/util/qsgsimplerectnode.cpp b/src/quick/scenegraph/util/qsgsimplerectnode.cpp
index 7b96a3fdde..0891f8d95c 100644
--- a/src/quick/scenegraph/util/qsgsimplerectnode.cpp
+++ b/src/quick/scenegraph/util/qsgsimplerectnode.cpp
@@ -51,8 +51,7 @@ QT_BEGIN_NAMESPACE
 
   \warning This utility class is only functional when running with the default
   or software backends of the Qt Quick scenegraph. As an alternative, prefer
-  using QSGRectangleNode via QQuickWindow::createRectangleNode() or
-  QSGEngine::createRectangleNode().
+  using QSGRectangleNode via QQuickWindow::createRectangleNode().
 
   \deprecated
  */
diff --git a/src/quick/scenegraph/util/qsgsimpletexturenode.cpp b/src/quick/scenegraph/util/qsgsimpletexturenode.cpp
index 1d0a423aa9..ff5c53d2ea 100644
--- a/src/quick/scenegraph/util/qsgsimpletexturenode.cpp
+++ b/src/quick/scenegraph/util/qsgsimpletexturenode.cpp
@@ -99,8 +99,7 @@ static void qsgsimpletexturenode_update(QSGGeometry *g,
 
   \warning This utility class is only functional when running with the default
   or software backends of the Qt Quick scenegraph. As an alternative, prefer
-  using QSGImageNode via QQuickWindow::createImageNode() or
-  QSGEngine::createImageNode().
+  using QSGImageNode via QQuickWindow::createImageNode().
 
   \deprecated
 */