Implemented texture cache for GL paint engine in QtGui.

This is simpler than the existing texture cache in QtOpenGL, as it only
serves the GL paint engine. There's one per context group, to simplify
the design and to prevent performance degradations.

Change-Id: I61e3c9a444d8e246a8b38da019a56f2c0a533c0c
Reviewed-on: http://codereview.qt-project.org/4674
Reviewed-by: Qt Sanity Bot <qt_sanity_bot@ovi.com>
Reviewed-by: Kim M. Kalland <kim.kalland@nokia.com>

7 files changed, 342 insertions, 118 deletions

diff --git a/src/gui/kernel/qopenglcontext.cpp b/src/gui/kernel/qopenglcontext.cpp
index d5b34c2f9b..22d003d4e9 100644
--- a/src/gui/kernel/qopenglcontext.cpp
+++ b/src/gui/kernel/qopenglcontext.cpp
@@ -566,6 +566,17 @@ QOpenGLSharedResource *QOpenGLMultiGroupSharedResource::value(QOpenGLContext *co
     return group->d_func()->m_resources.value(this, 0);
 }
 
+QList<QOpenGLSharedResource *> QOpenGLMultiGroupSharedResource::resources() const
+{
+    QList<QOpenGLSharedResource *> result;
+    for (QList<QOpenGLContextGroup *>::const_iterator it = m_groups.constBegin(); it != m_groups.constEnd(); ++it) {
+        QOpenGLSharedResource *resource = (*it)->d_func()->m_resources.value(const_cast<QOpenGLMultiGroupSharedResource *>(this), 0);
+        if (resource)
+            result << resource;
+    }
+    return result;
+}
+
 void QOpenGLMultiGroupSharedResource::cleanup(QOpenGLContext *ctx)
 {
     QOpenGLSharedResource *resource = value(ctx);
diff --git a/src/gui/kernel/qopenglcontext_p.h b/src/gui/kernel/qopenglcontext_p.h
index bfe0f9dedf..059872c09f 100644
--- a/src/gui/kernel/qopenglcontext_p.h
+++ b/src/gui/kernel/qopenglcontext_p.h
@@ -154,6 +154,8 @@ public:
 
     QOpenGLSharedResource *value(QOpenGLContext *context);
 
+    QList<QOpenGLSharedResource *> resources() const;
+
     template <typename T>
     T *value(QOpenGLContext *context) {
         QOpenGLContextGroup *group = context->shareGroup();
diff --git a/src/gui/opengl/opengl.pri b/src/gui/opengl/opengl.pri
index 22fc05e56a..4ee7af4569 100644
--- a/src/gui/opengl/opengl.pri
+++ b/src/gui/opengl/opengl.pri
@@ -14,6 +14,7 @@ HEADERS += opengl/qopengl.h \
            opengl/qopenglshaderprogram.h \
            opengl/qopenglextensions_p.h \
            opengl/qopenglgradientcache_p.h \
+           opengl/qopengltexturecache_p.h \
            opengl/qopenglengineshadermanager_p.h \
            opengl/qopengl2pexvertexarray_p.h \
            opengl/qopenglpaintengine_p.h \
@@ -34,6 +35,7 @@ SOURCES += opengl/qopengl.cpp \
            opengl/qopenglbuffer.cpp \
            opengl/qopenglshaderprogram.cpp \
            opengl/qopenglgradientcache.cpp \
+           opengl/qopengltexturecache.cpp \
            opengl/qopenglengineshadermanager.cpp \
            opengl/qopengl2pexvertexarray.cpp \
            opengl/qopenglpaintengine.cpp \
diff --git a/src/gui/opengl/qopengl_p.h b/src/gui/opengl/qopengl_p.h
index 59368f1a7b..b09f9447db 100644
--- a/src/gui/opengl/qopengl_p.h
+++ b/src/gui/opengl/qopengl_p.h
@@ -80,99 +80,6 @@ private:
     QVector<int> m_offsets;
 };
 
-class QOpenGLTexture : public QOpenGLSharedResource {
-public:
-    QOpenGLTexture(QOpenGLContext *ctx, GLuint id, bool inverted)
-        : QOpenGLSharedResource(ctx->shareGroup())
-        , m_id(id)
-        , m_inverted(inverted)
-    {
-    }
-
-    GLuint id() const { return m_id; }
-    bool invertedY() const { return m_inverted; }
-
-protected:
-    void invalidateResource()
-    {
-        m_id = 0;
-    }
-
-    void freeResource(QOpenGLContext *)
-    {
-        glDeleteTextures(1, &m_id);
-    }
-
-private:
-    GLuint m_id;
-    bool m_inverted;
-};
-
-struct QOpenGLTextureCacheKey {
-    qint64 key;
-    QOpenGLContextGroup *group;
-};
-
-inline bool operator==(const QOpenGLTextureCacheKey &a, const QOpenGLTextureCacheKey &b)
-{
-    return a.key == b.key && a.group == b.group;
-}
-
-inline uint qHash(const QOpenGLTextureCacheKey &key)
-{
-    return qHash(key.key) ^ qHash(key.group);
-}
-
-class QPlatformPixmap;
-
-class QOpenGLTextureCache {
-public:
-    QOpenGLTextureCache();
-    ~QOpenGLTextureCache();
-
-    void insert(QOpenGLContext *ctx, qint64 key, QOpenGLTexture *texture, int cost);
-    void remove(qint64 key);
-    inline int size();
-    inline void setMaxCost(int newMax);
-    inline int maxCost();
-    inline QOpenGLTexture* getTexture(QOpenGLContext *ctx, qint64 key);
-
-    bool remove(QOpenGLContext *ctx, GLuint textureId);
-    void removeContextTextures(QOpenGLContext *ctx);
-    static QOpenGLTextureCache *instance();
-    static void cleanupTexturesForCacheKey(qint64 cacheKey);
-    static void cleanupTexturesForPixampData(QPlatformPixmap* pixmap);
-    static void cleanupBeforePixmapDestruction(QPlatformPixmap* pixmap);
-
-private:
-    QCache<QOpenGLTextureCacheKey, QOpenGLTexture> m_cache;
-    QReadWriteLock m_lock;
-};
-
-int QOpenGLTextureCache::size() {
-    QReadLocker locker(&m_lock);
-    return m_cache.size();
-}
-
-void QOpenGLTextureCache::setMaxCost(int newMax)
-{
-    QWriteLocker locker(&m_lock);
-    m_cache.setMaxCost(newMax);
-}
-
-int QOpenGLTextureCache::maxCost()
-{
-    QReadLocker locker(&m_lock);
-    return m_cache.maxCost();
-}
-
-QOpenGLTexture* QOpenGLTextureCache::getTexture(QOpenGLContext *ctx, qint64 key)
-{
-    QReadLocker locker(&m_lock);
-    const QOpenGLTextureCacheKey cacheKey = { key, ctx->shareGroup() };
-    return m_cache.object(cacheKey);
-}
-
 QT_END_NAMESPACE
 
 QT_END_HEADER
diff --git a/src/gui/opengl/qopenglpaintengine.cpp b/src/gui/opengl/qopenglpaintengine.cpp
index 519dd3b893..b29cedcdf9 100644
--- a/src/gui/opengl/qopenglpaintengine.cpp
+++ b/src/gui/opengl/qopenglpaintengine.cpp
@@ -65,6 +65,7 @@
 // #define QT_OPENGL_CACHE_AS_VBOS
 
 #include "qopenglgradientcache_p.h"
+#include "qopengltexturecache_p.h"
 #include "qopenglpaintengine_p.h"
 
 #include <string.h> //for memcpy
@@ -197,7 +198,7 @@ void QOpenGL2PaintEngineExPrivate::updateBrushTexture()
         QImage texImage = qt_imageForBrush(style, false);
 
         funcs.glActiveTexture(GL_TEXTURE0 + QT_BRUSH_TEXTURE_UNIT);
-        //ctx->d_func()->bindTexture(texImage, GL_TEXTURE_2D, GL_RGBA, QOpenGLContext::InternalBindOption);
+        QOpenGLTextureCache::cacheForContext(ctx)->bindTexture(ctx, texImage);
         updateTextureFilter(GL_TEXTURE_2D, GL_REPEAT, q->state()->renderHints & QPainter::SmoothPixmapTransform);
     }
     else if (style >= Qt::LinearGradientPattern && style <= Qt::ConicalGradientPattern) {
@@ -227,11 +228,9 @@ void QOpenGL2PaintEngineExPrivate::updateBrushTexture()
             currentBrushPixmap = currentBrushPixmap.scaled(max_texture_size, max_texture_size, Qt::KeepAspectRatio);
 
         funcs.glActiveTexture(GL_TEXTURE0 + QT_BRUSH_TEXTURE_UNIT);
-        QOpenGLTexture *tex = 0;//ctx->d_func()->bindTexture(currentBrushPixmap, GL_TEXTURE_2D, GL_RGBA,
-                                //                     QOpenGLContext::InternalBindOption |
-                                //                     QOpenGLContext::CanFlipNativePixmapBindOption);
+        QOpenGLTextureCache::cacheForContext(ctx)->bindTexture(ctx, currentBrushPixmap);
         updateTextureFilter(GL_TEXTURE_2D, GL_REPEAT, q->state()->renderHints & QPainter::SmoothPixmapTransform);
-        textureInvertedY = tex->invertedY();
+        textureInvertedY = false;
     }
     brushTextureDirty = false;
 }
@@ -1360,18 +1359,15 @@ void QOpenGL2PaintEngineEx::drawPixmap(const QRectF& dest, const QPixmap & pixma
     d->transferMode(ImageDrawingMode);
 
     d->funcs.glActiveTexture(GL_TEXTURE0 + QT_IMAGE_TEXTURE_UNIT);
-    QOpenGLTexture *texture = 0;
-//        ctx->d_func()->bindTexture(pixmap, GL_TEXTURE_2D, GL_RGBA, bindOptions);
+    GLuint id = QOpenGLTextureCache::cacheForContext(ctx)->bindTexture(ctx, pixmap);
 
-    GLfloat top = texture->invertedY() ? (pixmap.height() - src.top()) : src.top();
-    GLfloat bottom = texture->invertedY() ? (pixmap.height() - src.bottom()) : src.bottom();
-    QOpenGLRect srcRect(src.left(), top, src.right(), bottom);
+    QOpenGLRect srcRect(src.left(), src.top(), src.right(), src.bottom());
 
     bool isBitmap = pixmap.isQBitmap();
     bool isOpaque = !isBitmap && !pixmap.hasAlpha();
 
     d->updateTextureFilter(GL_TEXTURE_2D, GL_CLAMP_TO_EDGE,
-                           state()->renderHints & QPainter::SmoothPixmapTransform, texture->id());
+                           state()->renderHints & QPainter::SmoothPixmapTransform, id);
     d->drawTexture(dest, srcRect, pixmap.size(), isOpaque, isBitmap);
 }
 
@@ -1397,8 +1393,7 @@ void QOpenGL2PaintEngineEx::drawImage(const QRectF& dest, const QImage& image, c
 
     d->funcs.glActiveTexture(GL_TEXTURE0 + QT_IMAGE_TEXTURE_UNIT);
 
-    QOpenGLTexture *texture = 0;//ctx->d_func()->bindTexture(image, GL_TEXTURE_2D, GL_RGBA, bindOptions);
-    GLuint id = texture->id();
+    GLuint id = QOpenGLTextureCache::cacheForContext(ctx)->bindTexture(ctx, image);
 
     d->updateTextureFilter(GL_TEXTURE_2D, GL_CLAMP_TO_EDGE,
                            state()->renderHints & QPainter::SmoothPixmapTransform, id);
@@ -1907,24 +1902,14 @@ void QOpenGL2PaintEngineExPrivate::drawPixmapFragments(const QPainter::PixmapFra
     }
 
     funcs.glActiveTexture(GL_TEXTURE0 + QT_IMAGE_TEXTURE_UNIT);
-    QOpenGLTexture *texture = 0;//ctx->d_func()->bindTexture(pixmap, GL_TEXTURE_2D, GL_RGBA,
-                                //                     QOpenGLContext::InternalBindOption
-                                //                     | QOpenGLContext::CanFlipNativePixmapBindOption);
-
-    if (texture->invertedY()) {
-        // Flip texture y-coordinate.
-        QOpenGLPoint *data = textureCoordinateArray.data();
-        for (int i = 0; i < 6 * fragmentCount; ++i)
-            data[i].y = 1 - data[i].y;
-    }
-
+    GLuint id = QOpenGLTextureCache::cacheForContext(ctx)->bindTexture(ctx, pixmap);
     transferMode(ImageArrayDrawingMode);
 
     bool isBitmap = pixmap.isQBitmap();
     bool isOpaque = !isBitmap && (!pixmap.hasAlpha() || (hints & QPainter::OpaqueHint)) && allOpaque;
 
     updateTextureFilter(GL_TEXTURE_2D, GL_CLAMP_TO_EDGE,
-                           q->state()->renderHints & QPainter::SmoothPixmapTransform, texture->id());
+                           q->state()->renderHints & QPainter::SmoothPixmapTransform, id);
 
     // Setup for texture drawing
     currentBrush = noBrush;
diff --git a/src/gui/opengl/qopengltexturecache.cpp b/src/gui/opengl/qopengltexturecache.cpp
new file mode 100644
index 0000000000..067b7a9e20
--- /dev/null
+++ b/src/gui/opengl/qopengltexturecache.cpp
@@ -0,0 +1,215 @@
+/****************************************************************************
+**
+** Copyright (C) 2011 Nokia Corporation and/or its subsidiary(-ies).
+** All rights reserved.
+** Contact: Nokia Corporation (qt-info@nokia.com)
+**
+** This file is part of the QtGui module of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** GNU Lesser General Public License Usage
+** This file may be used under the terms of the GNU Lesser General Public
+** License version 2.1 as published by the Free Software Foundation and
+** appearing in the file LICENSE.LGPL included in the packaging of this
+** file. Please review the following information to ensure the GNU Lesser
+** General Public License version 2.1 requirements will be met:
+** http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
+**
+** In addition, as a special exception, Nokia gives you certain additional
+** rights. These rights are described in the Nokia Qt LGPL Exception
+** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU General
+** Public License version 3.0 as published by the Free Software Foundation
+** and appearing in the file LICENSE.GPL included in the packaging of this
+** file. Please review the following information to ensure the GNU General
+** Public License version 3.0 requirements will be met:
+** http://www.gnu.org/copyleft/gpl.html.
+**
+** Other Usage
+** Alternatively, this file may be used in accordance with the terms and
+** conditions contained in a signed written agreement between you and Nokia.
+**
+**
+**
+**
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#include "qopengltexturecache_p.h"
+#include <private/qopenglcontext_p.h>
+#include <private/qimagepixmapcleanuphooks_p.h>
+#include <qplatformpixmap_qpa.h>
+
+QT_BEGIN_NAMESPACE
+
+class QOpenGLTextureCacheWrapper
+{
+public:
+    QOpenGLTextureCacheWrapper()
+    {
+        QImagePixmapCleanupHooks::instance()->addPlatformPixmapModificationHook(cleanupTexturesForPixmapData);
+        QImagePixmapCleanupHooks::instance()->addPlatformPixmapDestructionHook(cleanupTexturesForPixmapData);
+        QImagePixmapCleanupHooks::instance()->addImageHook(cleanupTexturesForCacheKey);
+    }
+
+    ~QOpenGLTextureCacheWrapper()
+    {
+        QImagePixmapCleanupHooks::instance()->removePlatformPixmapModificationHook(cleanupTexturesForPixmapData);
+        QImagePixmapCleanupHooks::instance()->removePlatformPixmapDestructionHook(cleanupTexturesForPixmapData);
+        QImagePixmapCleanupHooks::instance()->removeImageHook(cleanupTexturesForCacheKey);
+    }
+
+    QOpenGLTextureCache *cacheForContext(QOpenGLContext *context) {
+        QMutexLocker lock(&m_mutex);
+        return m_resource.value<QOpenGLTextureCache>(context);
+    }
+
+    static void cleanupTexturesForCacheKey(qint64 key);
+    static void cleanupTexturesForPixmapData(QPlatformPixmap *pmd);
+
+private:
+    QOpenGLMultiGroupSharedResource m_resource;
+    QMutex m_mutex;
+};
+
+Q_GLOBAL_STATIC(QOpenGLTextureCacheWrapper, qt_texture_caches)
+
+QOpenGLTextureCache *QOpenGLTextureCache::cacheForContext(QOpenGLContext *context)
+{
+    return qt_texture_caches()->cacheForContext(context);
+}
+
+void QOpenGLTextureCacheWrapper::cleanupTexturesForCacheKey(qint64 key)
+{
+    QList<QOpenGLSharedResource *> resources = qt_texture_caches()->m_resource.resources();
+    for (QList<QOpenGLSharedResource *>::iterator it = resources.begin(); it != resources.end(); ++it)
+        static_cast<QOpenGLTextureCache *>(*it)->invalidate(key);
+}
+
+void QOpenGLTextureCacheWrapper::cleanupTexturesForPixmapData(QPlatformPixmap *pmd)
+{
+    cleanupTexturesForCacheKey(pmd->cacheKey());
+}
+
+QOpenGLTextureCache::QOpenGLTextureCache(QOpenGLContext *ctx)
+    : QOpenGLSharedResource(ctx->shareGroup())
+    , m_cache(64 * 1024) // 64 MB cache
+{
+}
+
+QOpenGLTextureCache::~QOpenGLTextureCache()
+{
+}
+
+GLuint QOpenGLTextureCache::bindTexture(QOpenGLContext *context, const QPixmap &pixmap)
+{
+    QMutexLocker locker(&m_mutex);
+    qint64 key = pixmap.cacheKey();
+
+    // A QPainter is active on the image - take the safe route and replace the texture.
+    if (!pixmap.paintingActive()) {
+        QOpenGLCachedTexture *entry = m_cache.object(key);
+        if (entry) {
+            glBindTexture(GL_TEXTURE_2D, entry->id());
+            return entry->id();
+        }
+    }
+
+    GLuint id = bindTexture(context, key, pixmap.toImage());
+    if (id > 0)
+        QImagePixmapCleanupHooks::enableCleanupHooks(pixmap);
+
+    return id;
+}
+
+GLuint QOpenGLTextureCache::bindTexture(QOpenGLContext *context, const QImage &image)
+{
+    QMutexLocker locker(&m_mutex);
+    qint64 key = image.cacheKey();
+
+    // A QPainter is active on the image - take the safe route and replace the texture.
+    if (!image.paintingActive()) {
+        QOpenGLCachedTexture *entry = m_cache.object(key);
+        if (entry) {
+            glBindTexture(GL_TEXTURE_2D, entry->id());
+            return entry->id();
+        }
+    }
+
+    GLuint id = bindTexture(context, key, image);
+    if (id > 0)
+        QImagePixmapCleanupHooks::enableCleanupHooks(image);
+
+    return id;
+}
+
+static inline void qgl_byteSwapImage(QImage &img)
+{
+    const int width = img.width();
+    const int height = img.height();
+
+    if (QSysInfo::ByteOrder == QSysInfo::LittleEndian)
+    {
+        for (int i = 0; i < height; ++i) {
+            uint *p = (uint *) img.scanLine(i);
+            for (int x = 0; x < width; ++x)
+                p[x] = ((p[x] << 16) & 0xff0000) | ((p[x] >> 16) & 0xff) | (p[x] & 0xff00ff00);
+        }
+    } else {
+        for (int i = 0; i < height; ++i) {
+            uint *p = (uint *) img.scanLine(i);
+            for (int x = 0; x < width; ++x)
+                p[x] = (p[x] << 8) | (p[x] >> 24);
+        }
+    }
+}
+
+GLuint QOpenGLTextureCache::bindTexture(QOpenGLContext *context, qint64 key, const QImage &image)
+{
+    GLuint id;
+    glGenTextures(1, &id);
+    glBindTexture(GL_TEXTURE_2D, id);
+
+    QImage tx = image.convertToFormat(QImage::Format_ARGB32_Premultiplied);
+
+    qgl_byteSwapImage(tx);
+
+    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, tx.width(), tx.height(), 0, GL_RGBA, GL_UNSIGNED_BYTE, const_cast<const QImage &>(tx).bits());
+
+    int cost = tx.width() * tx.height() * 4 / 1024;
+    m_cache.insert(key, new QOpenGLCachedTexture(id, context), cost);
+
+    return id;
+}
+
+void QOpenGLTextureCache::invalidate(qint64 key)
+{
+    QMutexLocker locker(&m_mutex);
+    m_cache.remove(key);
+}
+
+void QOpenGLTextureCache::invalidateResource()
+{
+    m_cache.clear();
+}
+
+void QOpenGLTextureCache::freeResource(QOpenGLContext *)
+{
+    Q_ASSERT(false); // the texture cache lives until the context group disappears
+}
+
+static void freeTexture(QOpenGLFunctions *, GLuint id)
+{
+    glDeleteTextures(1, &id);
+}
+
+QOpenGLCachedTexture::QOpenGLCachedTexture(GLuint id, QOpenGLContext *context)
+{
+    m_resource = new QOpenGLSharedResourceGuard(context, id, freeTexture);
+}
+
+QT_END_NAMESPACE
diff --git a/src/gui/opengl/qopengltexturecache_p.h b/src/gui/opengl/qopengltexturecache_p.h
new file mode 100644
index 0000000000..bdee9f4e83
--- /dev/null
+++ b/src/gui/opengl/qopengltexturecache_p.h
@@ -0,0 +1,102 @@
+/****************************************************************************
+**
+** Copyright (C) 2011 Nokia Corporation and/or its subsidiary(-ies).
+** All rights reserved.
+** Contact: Nokia Corporation (qt-info@nokia.com)
+**
+** This file is part of the QtGui module of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** GNU Lesser General Public License Usage
+** This file may be used under the terms of the GNU Lesser General Public
+** License version 2.1 as published by the Free Software Foundation and
+** appearing in the file LICENSE.LGPL included in the packaging of this
+** file. Please review the following information to ensure the GNU Lesser
+** General Public License version 2.1 requirements will be met:
+** http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
+**
+** In addition, as a special exception, Nokia gives you certain additional
+** rights. These rights are described in the Nokia Qt LGPL Exception
+** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU General
+** Public License version 3.0 as published by the Free Software Foundation
+** and appearing in the file LICENSE.GPL included in the packaging of this
+** file. Please review the following information to ensure the GNU General
+** Public License version 3.0 requirements will be met:
+** http://www.gnu.org/copyleft/gpl.html.
+**
+** Other Usage
+** Alternatively, this file may be used in accordance with the terms and
+** conditions contained in a signed written agreement between you and Nokia.
+**
+**
+**
+**
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+//
+//  W A R N I N G
+//  -------------
+//
+// This file is not part of the Qt API.  It exists purely as an
+// implementation detail.  This header file may change from version to
+// version without notice, or even be removed.
+//
+// We mean it.
+//
+
+#ifndef QOPENGLTEXTURECACHE_P_H
+#define QOPENGLTEXTURECACHE_P_H
+
+#include <QHash>
+#include <QObject>
+#include <QtGui/QtGui>
+#include <private/qopenglcontext_p.h>
+#include <QtCore/qmutex.h>
+
+QT_BEGIN_NAMESPACE
+
+class QOpenGLCachedTexture
+{
+public:
+    QOpenGLCachedTexture(GLuint id, QOpenGLContext *context);
+    ~QOpenGLCachedTexture() { m_resource->free(); }
+
+    GLuint id() const { return m_resource->id(); }
+
+private:
+    QOpenGLSharedResourceGuard *m_resource;
+};
+
+class QOpenGLTextureCache : public QOpenGLSharedResource
+{
+public:
+    static QOpenGLTextureCache *cacheForContext(QOpenGLContext *context);
+
+    QOpenGLTextureCache(QOpenGLContext *);
+    ~QOpenGLTextureCache();
+
+    GLuint bindTexture(QOpenGLContext *context, const QPixmap &pixmap);
+    GLuint bindTexture(QOpenGLContext *context, const QImage &image);
+
+    void invalidate(qint64 key);
+
+    void invalidateResource();
+    void freeResource(QOpenGLContext *ctx);
+
+private:
+    GLuint bindTexture(QOpenGLContext *context, qint64 key, const QImage &image);
+
+    QMutex m_mutex;
+    QCache<quint64, QOpenGLCachedTexture> m_cache;
+};
+
+QT_END_NAMESPACE
+
+#endif
+