Initial implementation of GLES2.0 resource pooling

Keep the implementation in separate
qpixmapdata_poolgl.cpp file until the pooling has
been verified and confirmed to work ok.

Task-number: QTBUG-15253 QTBUG-17850
Reviewed-by: Samuel Rødal

12 files changed, 1467 insertions, 17 deletions

diff --git a/src/opengl/gl2paintengineex/qpaintengineex_opengl2.cpp b/src/opengl/gl2paintengineex/qpaintengineex_opengl2.cpp
index cda31e5..c8786fb 100644
--- a/src/opengl/gl2paintengineex/qpaintengineex_opengl2.cpp
+++ b/src/opengl/gl2paintengineex/qpaintengineex_opengl2.cpp
@@ -1335,11 +1335,14 @@ void QGL2PaintEngineEx::drawPixmap(const QRectF& dest, const QPixmap & pixmap, c
     ensureActive();
     d->transferMode(ImageDrawingMode);
 
+    QGLContext::BindOptions bindOptions = QGLContext::InternalBindOption|QGLContext::CanFlipNativePixmapBindOption;
+#ifdef QGL_USE_TEXTURE_POOL
+    bindOptions |= QGLContext::TemporarilyCachedBindOption;
+#endif
+
     glActiveTexture(GL_TEXTURE0 + QT_IMAGE_TEXTURE_UNIT);
     QGLTexture *texture =
-        ctx->d_func()->bindTexture(pixmap, GL_TEXTURE_2D, GL_RGBA,
-                                   QGLContext::InternalBindOption
-                                   | QGLContext::CanFlipNativePixmapBindOption);
+        ctx->d_func()->bindTexture(pixmap, GL_TEXTURE_2D, GL_RGBA, bindOptions);
 
     GLfloat top = texture->options & QGLContext::InvertedYBindOption ? (pixmap.height() - src.top()) : src.top();
     GLfloat bottom = texture->options & QGLContext::InvertedYBindOption ? (pixmap.height() - src.bottom()) : src.bottom();
@@ -1351,6 +1354,12 @@ void QGL2PaintEngineEx::drawPixmap(const QRectF& dest, const QPixmap & pixmap, c
     d->updateTextureFilter(GL_TEXTURE_2D, GL_CLAMP_TO_EDGE,
                            state()->renderHints & QPainter::SmoothPixmapTransform, texture->id);
     d->drawTexture(dest, srcRect, pixmap.size(), isOpaque, isBitmap);
+
+    if (texture->options&QGLContext::TemporarilyCachedBindOption) {
+        // pixmap was temporarily cached as a QImage texture by pooling system
+        // and should be destroyed immediately
+        QGLTextureCache::instance()->remove(ctx, texture->id);
+    }
 }
 
 void QGL2PaintEngineEx::drawImage(const QRectF& dest, const QImage& image, const QRectF& src,
@@ -1375,12 +1384,23 @@ void QGL2PaintEngineEx::drawImage(const QRectF& dest, const QImage& image, const
 
     glActiveTexture(GL_TEXTURE0 + QT_IMAGE_TEXTURE_UNIT);
 
-    QGLTexture *texture = ctx->d_func()->bindTexture(image, GL_TEXTURE_2D, GL_RGBA, QGLContext::InternalBindOption);
+    QGLContext::BindOptions bindOptions = QGLContext::InternalBindOption;
+#ifdef QGL_USE_TEXTURE_POOL
+    bindOptions |= QGLContext::TemporarilyCachedBindOption;
+#endif
+
+    QGLTexture *texture = ctx->d_func()->bindTexture(image, GL_TEXTURE_2D, GL_RGBA, bindOptions);
     GLuint id = texture->id;
 
     d->updateTextureFilter(GL_TEXTURE_2D, GL_CLAMP_TO_EDGE,
                            state()->renderHints & QPainter::SmoothPixmapTransform, id);
     d->drawTexture(dest, src, image.size(), !image.hasAlphaChannel());
+
+    if (texture->options&QGLContext::TemporarilyCachedBindOption) {
+        // image was temporarily cached by texture pooling system
+        // and should be destroyed immediately
+        QGLTextureCache::instance()->remove(ctx, texture->id);
+    }
 }
 
 void QGL2PaintEngineEx::drawStaticTextItem(QStaticTextItem *textItem)
diff --git a/src/opengl/opengl.pro b/src/opengl/opengl.pro
index 0e82467..6bbf99b 100644
--- a/src/opengl/opengl.pro
+++ b/src/opengl/opengl.pro
@@ -148,11 +148,16 @@ embedded {
 }
 
 symbian {
+    DEFINES += QGL_USE_TEXTURE_POOL
+    SOURCES -= qpixmapdata_gl.cpp
     SOURCES += qgl_symbian.cpp \
+               qpixmapdata_poolgl.cpp \
                qglpixelbuffer_egl.cpp \
-               qgl_egl.cpp
+               qgl_egl.cpp \
+               qgltexturepool.cpp
 
-    HEADERS += qgl_egl_p.h
+    HEADERS += qgl_egl_p.h \
+               qgltexturepool_p.h
 
     symbian:TARGET.UID3 = 0x2002131A
 }
diff --git a/src/opengl/qgl.cpp b/src/opengl/qgl.cpp
index 062218c..ded7aa8 100644
--- a/src/opengl/qgl.cpp
+++ b/src/opengl/qgl.cpp
@@ -93,6 +93,10 @@
 #include "qlibrary.h"
 #include <qmutex.h>
 
+#ifdef QGL_USE_TEXTURE_POOL
+#include <private/qgltexturepool_p.h>
+#endif
+
 
 QT_BEGIN_NAMESPACE
 
@@ -2022,6 +2026,10 @@ struct DDSFormat {
     the pixmap/image that it stems from, e.g. installing destruction
     hooks in them.
 
+    \omitvalue TemporarilyCachedBindOption Used by paint engines on some
+    platforms to indicate that the pixmap or image texture is possibly
+    cached only temporarily and must be destroyed immediately after the use.
+
     \omitvalue InternalBindOption
 */
 
@@ -2529,8 +2537,18 @@ QGLTexture* QGLContextPrivate::bindTexture(const QImage &image, GLenum target, G
 #endif
 
     const QImage &constRef = img; // to avoid detach in bits()...
+#ifdef QGL_USE_TEXTURE_POOL
+    QGLTexturePool::instance()->createPermanentTexture(tx_id,
+                                                        target,
+                                                        0, internalFormat,
+                                                        img.width(), img.height(),
+                                                        externalFormat,
+                                                        pixel_type,
+                                                        constRef.bits());
+#else
     glTexImage2D(target, 0, internalFormat, img.width(), img.height(), 0, externalFormat,
                  pixel_type, constRef.bits());
+#endif
 #if defined(QT_OPENGL_ES_2)
     if (genMipmap)
         glGenerateMipmap(target);
@@ -2569,7 +2587,6 @@ QGLTexture *QGLContextPrivate::textureCacheLookup(const qint64 key, GLenum targe
     return 0;
 }
 
-
 /*! \internal */
 QGLTexture *QGLContextPrivate::bindTexture(const QPixmap &pixmap, GLenum target, GLint format, QGLContext::BindOptions options)
 {
diff --git a/src/opengl/qgl.h b/src/opengl/qgl.h
index 9443c74..7d72c8a 100644
--- a/src/opengl/qgl.h
+++ b/src/opengl/qgl.h
@@ -329,6 +329,7 @@ public:
 
         MemoryManagedBindOption                 = 0x0010, // internal flag
         CanFlipNativePixmapBindOption           = 0x0020, // internal flag
+        TemporarilyCachedBindOption             = 0x0040, // internal flag
 
         DefaultBindOption                       = LinearFilteringBindOption
                                                   | InvertedYBindOption
diff --git a/src/opengl/qgl_symbian.cpp b/src/opengl/qgl_symbian.cpp
index a9e2248..2978514 100644
--- a/src/opengl/qgl_symbian.cpp
+++ b/src/opengl/qgl_symbian.cpp
@@ -52,6 +52,7 @@
 #include <private/qwidget_p.h> // to access QWExtra
 #include "qgl_egl_p.h"
 #include "qpixmapdata_gl_p.h"
+#include "qgltexturepool_p.h"
 #include "qcolormap.h"
 #include <QDebug>
 
diff --git a/src/opengl/qgltexturepool.cpp b/src/opengl/qgltexturepool.cpp
new file mode 100644
index 0000000..61a88c3
--- /dev/null
+++ b/src/opengl/qgltexturepool.cpp
@@ -0,0 +1,241 @@
+/****************************************************************************
+**
+** 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 QtOpenVG module of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** No Commercial Usage
+** This file contains pre-release code and may not be distributed.
+** You may use this file in accordance with the terms and conditions
+** contained in the Technology Preview License Agreement accompanying
+** this package.
+**
+** GNU Lesser General Public License Usage
+** Alternatively, 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.
+**
+** If you have questions regarding the use of this file, please contact
+** Nokia at qt-info@nokia.com.
+**
+**
+**
+**
+**
+**
+**
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#include "qgltexturepool_p.h"
+#include "qpixmapdata_gl_p.h"
+
+QT_BEGIN_NAMESPACE
+
+Q_OPENGL_EXPORT extern QGLWidget* qt_gl_share_widget();
+
+static QGLTexturePool *qt_gl_texture_pool = 0;
+
+class QGLTexturePoolPrivate
+{
+public:
+    QGLTexturePoolPrivate() : lruFirst(0), lruLast(0) {}
+
+    QGLPixmapData *lruFirst;
+    QGLPixmapData *lruLast;
+};
+
+QGLTexturePool::QGLTexturePool()
+    : d_ptr(new QGLTexturePoolPrivate())
+{
+}
+
+QGLTexturePool::~QGLTexturePool()
+{
+}
+
+QGLTexturePool *QGLTexturePool::instance()
+{
+    if (!qt_gl_texture_pool)
+        qt_gl_texture_pool = new QGLTexturePool();
+    return qt_gl_texture_pool;
+}
+
+GLuint QGLTexturePool::createTextureForPixmap(GLenum target,
+                                            GLint level,
+                                            GLint internalformat,
+                                            GLsizei width,
+                                            GLsizei height,
+                                            GLenum format,
+                                            GLenum type,
+                                            QGLPixmapData *data)
+{
+    GLuint texture;
+    glGenTextures(1, &texture);
+    glBindTexture(target, texture);
+    do {
+        glTexImage2D(target, level, internalformat, width, height, 0, format, type, 0);
+        GLenum error = glGetError();
+        if (error == GL_NO_ERROR) {
+            if (data)
+                moveToHeadOfLRU(data);
+            return texture;
+        } else if (error != GL_OUT_OF_MEMORY) {
+            qWarning("QGLTexturePool: cannot create temporary texture because of invalid params");
+            return 0;
+        }
+    } while (reclaimSpace(internalformat, width, height, format, type, data));
+    qWarning("QGLTexturePool: cannot reclaim sufficient space for a %dx%d pixmap",
+             width, height);
+    return 0;
+}
+
+bool QGLTexturePool::createPermanentTexture(GLuint texture,
+                                            GLenum target,
+                                            GLint level,
+                                            GLint internalformat,
+                                            GLsizei width,
+                                            GLsizei height,
+                                            GLenum format,
+                                            GLenum type,
+                                            const GLvoid *data)
+{
+    glBindTexture(target, texture);
+    do {
+        glTexImage2D(target, level, internalformat, width, height, 0, format, type, data);
+
+        GLenum error = glGetError();
+        if (error == GL_NO_ERROR) {
+            return true;
+        } else if (error != GL_OUT_OF_MEMORY) {
+            qWarning("QGLTexturePool: cannot create permanent texture because of invalid params");
+            return false;
+        }
+    } while (reclaimSpace(internalformat, width, height, format, type, 0));
+    qWarning("QGLTexturePool: cannot reclaim sufficient space for a %dx%d pixmap",
+             width, height);
+    return 0;
+}
+
+void QGLTexturePool::releaseTexture(QGLPixmapData *data, GLuint texture)
+{
+    // Very simple strategy at the moment: just destroy the texture.
+    if (data)
+        removeFromLRU(data);
+
+    QGLShareContextScope ctx(qt_gl_share_widget()->context());
+    glDeleteTextures(1, &texture);
+}
+
+void QGLTexturePool::useTexture(QGLPixmapData *data)
+{
+    moveToHeadOfLRU(data);
+}
+
+void QGLTexturePool::detachTexture(QGLPixmapData *data)
+{
+    removeFromLRU(data);
+}
+
+bool QGLTexturePool::reclaimSpace(GLint internalformat,
+                                    GLsizei width,
+                                    GLsizei height,
+                                    GLenum format,
+                                    GLenum type,
+                                    QGLPixmapData *data)
+{
+    Q_UNUSED(internalformat);   // For future use in picking the best texture to eject.
+    Q_UNUSED(width);
+    Q_UNUSED(height);
+    Q_UNUSED(format);
+    Q_UNUSED(type);
+
+    bool succeeded = false;
+    bool wasInLRU = false;
+    if (data) {
+        wasInLRU = data->inLRU;
+        moveToHeadOfLRU(data);
+    }
+
+    QGLPixmapData *lrudata = pixmapLRU();
+    if (lrudata && lrudata != data) {
+        lrudata->reclaimTexture();
+        succeeded = true;
+    }
+
+    if (data && !wasInLRU)
+        removeFromLRU(data);
+
+    return succeeded;
+}
+
+void QGLTexturePool::hibernate()
+{
+    Q_D(QGLTexturePool);
+    QGLPixmapData *pd = d->lruLast;
+    while (pd) {
+        QGLPixmapData *prevLRU = pd->prevLRU;
+        pd->inTexturePool = false;
+        pd->inLRU = false;
+        pd->nextLRU = 0;
+        pd->prevLRU = 0;
+        pd->hibernate();
+        pd = prevLRU;
+    }
+    d->lruFirst = 0;
+    d->lruLast = 0;
+}
+
+void QGLTexturePool::moveToHeadOfLRU(QGLPixmapData *data)
+{
+    Q_D(QGLTexturePool);
+    if (data->inLRU) {
+        if (!data->prevLRU)
+            return;     // Already at the head of the list.
+        removeFromLRU(data);
+    }
+    data->inLRU = true;
+    data->nextLRU = d->lruFirst;
+    data->prevLRU = 0;
+    if (d->lruFirst)
+        d->lruFirst->prevLRU = data;
+    else
+        d->lruLast = data;
+    d->lruFirst = data;
+}
+
+void QGLTexturePool::removeFromLRU(QGLPixmapData *data)
+{
+    Q_D(QGLTexturePool);
+    if (!data->inLRU)
+        return;
+    if (data->nextLRU)
+        data->nextLRU->prevLRU = data->prevLRU;
+    else
+        d->lruLast = data->prevLRU;
+    if (data->prevLRU)
+        data->prevLRU->nextLRU = data->nextLRU;
+    else
+        d->lruFirst = data->nextLRU;
+    data->inLRU = false;
+}
+
+QGLPixmapData *QGLTexturePool::pixmapLRU()
+{
+    Q_D(QGLTexturePool);
+    return d->lruLast;
+}
+
+QT_END_NAMESPACE
diff --git a/src/opengl/qgltexturepool_p.h b/src/opengl/qgltexturepool_p.h
new file mode 100644
index 0000000..8b6f726
--- /dev/null
+++ b/src/opengl/qgltexturepool_p.h
@@ -0,0 +1,147 @@
+/****************************************************************************
+**
+** 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 QtOpenVG module of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** No Commercial Usage
+** This file contains pre-release code and may not be distributed.
+** You may use this file in accordance with the terms and conditions
+** contained in the Technology Preview License Agreement accompanying
+** this package.
+**
+** GNU Lesser General Public License Usage
+** Alternatively, 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.
+**
+** If you have questions regarding the use of this file, please contact
+** Nokia at qt-info@nokia.com.
+**
+**
+**
+**
+**
+**
+**
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#ifndef QGLTEXTUREPOOL_P_H
+#define QGLTEXTUREPOOL_P_H
+
+//
+//  W A R N I N G
+//  -------------
+//
+// This file is not part of the Qt API.  It exists for the convenience
+// of other Qt classes.  This header file may change from version to
+// version without notice, or even be removed.
+//
+// We mean it.
+//
+
+#include "qgl.h"
+#include <QtCore/qscopedpointer.h>
+
+QT_BEGIN_NAMESPACE
+
+class QGLPixmapData;
+class QGLTexturePoolPrivate;
+
+class QGLTexturePool
+{
+public:
+    QGLTexturePool();
+    virtual ~QGLTexturePool();
+
+    static QGLTexturePool *instance();
+
+    // Create a new texture with the specified parameters and associate
+    // it with "data".  The QGLPixmapData will be notified when the
+    // texture needs to be reclaimed by the pool.
+    //
+    // This function will call reclaimSpace() when texture creation fails.
+    GLuint createTextureForPixmap(GLenum target,
+                                            GLint level,
+                                            GLint internalformat,
+                                            GLsizei width,
+                                            GLsizei height,
+                                            GLenum format,
+                                            GLenum type,
+                                            QGLPixmapData *data);
+
+    // Create a permanent texture with the specified parameters.
+    // If there is insufficient space for the texture,
+    // then this function will call reclaimSpace() and try again.
+    //
+    // The caller is responsible for calling glDeleteTextures()
+    // when it no longer needs the texture, as the texture is not
+    // recorded in the texture pool.
+    bool createPermanentTexture(GLuint texture,
+                                            GLenum target,
+                                            GLint level,
+                                            GLint internalformat,
+                                            GLsizei width,
+                                            GLsizei height,
+                                            GLenum format,
+                                            GLenum type,
+                                            const GLvoid *data);
+
+    // Release a texture that is no longer required.
+    void releaseTexture(QGLPixmapData *data, GLuint texture);
+
+    // Notify the pool that a QGLPixmapData object is using
+    // an texture again.  This allows the pool to move the texture
+    // within a least-recently-used list of QGLPixmapData objects.
+    void useTexture(QGLPixmapData *data);
+
+    // Notify the pool that the texture associated with a
+    // QGLPixmapData is being detached from the pool.  The caller
+    // will become responsible for calling glDeleteTextures().
+    void detachTexture(QGLPixmapData *data);
+
+    // Reclaim space for an image allocation with the specified parameters.
+    // Returns true if space was reclaimed, or false if there is no
+    // further space that can be reclaimed.  The "data" parameter
+    // indicates the pixmap that is trying to obtain space which should
+    // not itself be reclaimed.
+    bool reclaimSpace(GLint internalformat,
+                                GLsizei width,
+                                GLsizei height,
+                                GLenum format,
+                                GLenum type,
+                                QGLPixmapData *data);
+
+    // Hibernate the image pool because the context is about to be
+    // destroyed.  All textures left in the pool should be released.
+    void hibernate();
+
+protected:
+    // Helper functions for managing the LRU list of QGLPixmapData objects.
+    void moveToHeadOfLRU(QGLPixmapData *data);
+    void removeFromLRU(QGLPixmapData *data);
+    QGLPixmapData *pixmapLRU();
+
+private:
+    QScopedPointer<QGLTexturePoolPrivate> d_ptr;
+
+    Q_DECLARE_PRIVATE(QGLTexturePool)
+    Q_DISABLE_COPY(QGLTexturePool)
+};
+
+QT_END_NAMESPACE
+
+#endif
diff --git a/src/opengl/qgraphicssystem_gl.cpp b/src/opengl/qgraphicssystem_gl.cpp
index 3574756..0aa3c2e 100644
--- a/src/opengl/qgraphicssystem_gl.cpp
+++ b/src/opengl/qgraphicssystem_gl.cpp
@@ -57,6 +57,10 @@
 #include <QtGui/private/qapplication_p.h>
 #endif
 
+#ifdef QGL_USE_TEXTURE_POOL
+#include "private/qgltexturepool_p.h"
+#endif
+
 QT_BEGIN_NAMESPACE
 
 extern QGLWidget *qt_gl_getShareWidget();
@@ -100,6 +104,11 @@ QWindowSurface *QGLGraphicsSystem::createWindowSurface(QWidget *widget) const
 
     return new QGLWindowSurface(widget);
 }
-
+#ifdef QGL_USE_TEXTURE_POOL
+void QGLGraphicsSystem::releaseCachedResources()
+{
+    QGLTexturePool::instance()->hibernate();
+}
+#endif
 QT_END_NAMESPACE
 
diff --git a/src/opengl/qgraphicssystem_gl_p.h b/src/opengl/qgraphicssystem_gl_p.h
index 4630da1..5829dcc 100644
--- a/src/opengl/qgraphicssystem_gl_p.h
+++ b/src/opengl/qgraphicssystem_gl_p.h
@@ -66,6 +66,10 @@ public:
 
     QPixmapData *createPixmapData(QPixmapData::PixelType type) const;
     QWindowSurface *createWindowSurface(QWidget *widget) const;
+
+#ifdef QGL_USE_TEXTURE_POOL
+    void releaseCachedResources();
+#endif
 private:
     bool m_useX11GL;
 };
diff --git a/src/opengl/qpixmapdata_gl_p.h b/src/opengl/qpixmapdata_gl_p.h
index a4066fd..55cc29d 100644
--- a/src/opengl/qpixmapdata_gl_p.h
+++ b/src/opengl/qpixmapdata_gl_p.h
@@ -66,6 +66,12 @@ class QGLFramebufferObject;
 class QGLFramebufferObjectFormat;
 class QGLPixmapData;
 
+#ifdef QGL_USE_TEXTURE_POOL
+void qt_gl_register_pixmap(QGLPixmapData *pd);
+void qt_gl_unregister_pixmap(QGLPixmapData *pd);
+void qt_gl_hibernate_pixmaps();
+#endif
+
 class QGLFramebufferObjectPool
 {
 public:
@@ -129,7 +135,24 @@ public:
     GLuint bind(bool copyBack = true) const;
     QGLTexture *texture() const;
 
-#if defined(Q_OS_SYMBIAN)
+#ifdef QGL_USE_TEXTURE_POOL
+    void destroyTexture();
+    // Detach this image from the image pool.
+    void detachTextureFromPool();
+    // Release the GL resources associated with this pixmap and copy
+    // the pixmap's contents out of the GPU back into main memory.
+    // The GL resource will be automatically recreated the next time
+    // ensureCreated() is called.  Does nothing if the pixmap cannot be
+    // hibernated for some reason (e.g. texture is shared with another
+    // process via a SgImage).
+    void hibernate();
+    // Called when the QGLTexturePool wants to reclaim this pixmap's
+    // texture objects to reuse storage.
+    void reclaimTexture();
+    void forceToImage();
+#endif
+
+#ifdef Q_OS_SYMBIAN
     void* toNativeType(NativeType type);
     void fromNativeType(void* pixmap, NativeType type);
 #endif
@@ -176,6 +199,23 @@ private:
 
     mutable QGLPixmapGLPaintDevice m_glDevice;
 
+#ifdef QGL_USE_TEXTURE_POOL
+    QGLPixmapData *nextLRU;
+    QGLPixmapData *prevLRU;
+    mutable bool inLRU;
+    mutable bool failedToAlloc;
+    mutable bool inTexturePool;
+
+    QGLPixmapData *next;
+    QGLPixmapData *prev;
+
+    friend class QGLTexturePool;
+
+    friend void qt_gl_register_pixmap(QGLPixmapData *pd);
+    friend void qt_gl_unregister_pixmap(QGLPixmapData *pd);
+    friend void qt_gl_hibernate_pixmaps();
+#endif
+
     friend class QGLPixmapGLPaintDevice;
     friend class QMeeGoPixmapData;
     friend class QMeeGoLivePixmapData;
diff --git a/src/opengl/qpixmapdata_poolgl.cpp b/src/opengl/qpixmapdata_poolgl.cpp
new file mode 100644
index 0000000..f1220b1
--- /dev/null
+++ b/src/opengl/qpixmapdata_poolgl.cpp
@@ -0,0 +1,902 @@
+/****************************************************************************
+**
+** 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 QtOpenGL module of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** No Commercial Usage
+** This file contains pre-release code and may not be distributed.
+** You may use this file in accordance with the terms and conditions
+** contained in the Technology Preview License Agreement accompanying
+** this package.
+**
+** GNU Lesser General Public License Usage
+** Alternatively, 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.
+**
+** If you have questions regarding the use of this file, please contact
+** Nokia at qt-info@nokia.com.
+**
+**
+**
+**
+**
+**
+**
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#include "qpixmap.h"
+#include "qglframebufferobject.h"
+
+#include <private/qpaintengine_raster_p.h>
+
+#include "qpixmapdata_gl_p.h"
+
+#include <private/qgl_p.h>
+#include <private/qdrawhelper_p.h>
+#include <private/qimage_p.h>
+
+#include <private/qpaintengineex_opengl2_p.h>
+
+#include <qdesktopwidget.h>
+#include <qfile.h>
+#include <qimagereader.h>
+#include <qbuffer.h>
+
+#include "qgltexturepool_p.h"
+
+QT_BEGIN_NAMESPACE
+
+Q_OPENGL_EXPORT extern QGLWidget* qt_gl_share_widget();
+
+/*!
+    \class QGLFramebufferObjectPool
+    \since 4.6
+
+    \brief The QGLFramebufferObject class provides a pool of framebuffer
+    objects for offscreen rendering purposes.
+
+    When requesting an FBO of a given size and format, an FBO of the same
+    format and a size at least as big as the requested size will be returned.
+
+    \internal
+*/
+
+static inline int areaDiff(const QSize &size, const QGLFramebufferObject *fbo)
+{
+    return qAbs(size.width() * size.height() - fbo->width() * fbo->height());
+}
+
+extern int qt_next_power_of_two(int v);
+
+static inline QSize maybeRoundToNextPowerOfTwo(const QSize &sz)
+{
+#ifdef QT_OPENGL_ES_2
+    QSize rounded(qt_next_power_of_two(sz.width()), qt_next_power_of_two(sz.height()));
+    if (rounded.width() * rounded.height() < 1.20 * sz.width() * sz.height())
+        return rounded;
+#endif
+    return sz;
+}
+
+
+QGLFramebufferObject *QGLFramebufferObjectPool::acquire(const QSize &requestSize, const QGLFramebufferObjectFormat &requestFormat, bool strictSize)
+{
+    QGLFramebufferObject *chosen = 0;
+    QGLFramebufferObject *candidate = 0;
+    for (int i = 0; !chosen && i < m_fbos.size(); ++i) {
+        QGLFramebufferObject *fbo = m_fbos.at(i);
+
+        if (strictSize) {
+            if (fbo->size() == requestSize && fbo->format() == requestFormat) {
+                chosen = fbo;
+                break;
+            } else {
+                continue;
+            }
+        }
+
+        if (fbo->format() == requestFormat) {
+            // choose the fbo with a matching format and the closest size
+            if (!candidate || areaDiff(requestSize, candidate) > areaDiff(requestSize, fbo))
+                candidate = fbo;
+        }
+
+        if (candidate) {
+            m_fbos.removeOne(candidate);
+
+            const QSize fboSize = candidate->size();
+            QSize sz = fboSize;
+
+            if (sz.width() < requestSize.width())
+                sz.setWidth(qMax(requestSize.width(), qRound(sz.width() * 1.5)));
+            if (sz.height() < requestSize.height())
+                sz.setHeight(qMax(requestSize.height(), qRound(sz.height() * 1.5)));
+
+            // wasting too much space?
+            if (sz.width() * sz.height() > requestSize.width() * requestSize.height() * 4)
+                sz = requestSize;
+
+            if (sz != fboSize) {
+                delete candidate;
+                candidate = new QGLFramebufferObject(maybeRoundToNextPowerOfTwo(sz), requestFormat);
+            }
+
+            chosen = candidate;
+        }
+    }
+
+    if (!chosen) {
+        if (strictSize)
+            chosen = new QGLFramebufferObject(requestSize, requestFormat);
+        else
+            chosen = new QGLFramebufferObject(maybeRoundToNextPowerOfTwo(requestSize), requestFormat);
+    }
+
+    if (!chosen->isValid()) {
+        delete chosen;
+        chosen = 0;
+    }
+
+    return chosen;
+}
+
+void QGLFramebufferObjectPool::release(QGLFramebufferObject *fbo)
+{
+    if (fbo)
+        m_fbos << fbo;
+}
+
+
+QPaintEngine* QGLPixmapGLPaintDevice::paintEngine() const
+{
+    return data->paintEngine();
+}
+
+void QGLPixmapGLPaintDevice::beginPaint()
+{
+    if (!data->isValid())
+        return;
+
+    // QGLPaintDevice::beginPaint will store the current binding and replace
+    // it with m_thisFBO:
+    m_thisFBO = data->m_renderFbo->handle();
+    QGLPaintDevice::beginPaint();
+
+    Q_ASSERT(data->paintEngine()->type() == QPaintEngine::OpenGL2);
+
+    // QPixmap::fill() is deferred until now, where we actually need to do the fill:
+    if (data->needsFill()) {
+        const QColor &c = data->fillColor();
+        float alpha = c.alphaF();
+        glDisable(GL_SCISSOR_TEST);
+        glClearColor(c.redF() * alpha, c.greenF() * alpha, c.blueF() * alpha, alpha);
+        glClear(GL_COLOR_BUFFER_BIT);
+    }
+    else if (!data->isUninitialized()) {
+        // If the pixmap (GL Texture) has valid content (it has been
+        // uploaded from an image or rendered into before), we need to
+        // copy it from the texture to the render FBO.
+
+        glDisable(GL_DEPTH_TEST);
+        glDisable(GL_SCISSOR_TEST);
+        glDisable(GL_BLEND);
+
+#if !defined(QT_OPENGL_ES_2)
+        glMatrixMode(GL_MODELVIEW);
+        glLoadIdentity();
+
+        glMatrixMode(GL_PROJECTION);
+        glLoadIdentity();
+        glOrtho(0, data->width(), data->height(), 0, -999999, 999999);
+#endif
+
+        glViewport(0, 0, data->width(), data->height());
+
+        // Pass false to bind so it doesn't copy the FBO into the texture!
+        context()->drawTexture(QRect(0, 0, data->width(), data->height()), data->bind(false));
+    }
+}
+
+void QGLPixmapGLPaintDevice::endPaint()
+{
+    if (!data->isValid())
+        return;
+
+    data->copyBackFromRenderFbo(false);
+
+    // Base's endPaint will restore the previous FBO binding
+    QGLPaintDevice::endPaint();
+
+    qgl_fbo_pool()->release(data->m_renderFbo);
+    data->m_renderFbo = 0;
+}
+
+QGLContext* QGLPixmapGLPaintDevice::context() const
+{
+    data->ensureCreated();
+    return data->m_ctx;
+}
+
+QSize QGLPixmapGLPaintDevice::size() const
+{
+    return data->size();
+}
+
+bool QGLPixmapGLPaintDevice::alphaRequested() const
+{
+    return data->m_hasAlpha;
+}
+
+void QGLPixmapGLPaintDevice::setPixmapData(QGLPixmapData* d)
+{
+    data = d;
+}
+
+static int qt_gl_pixmap_serial = 0;
+
+QGLPixmapData::QGLPixmapData(PixelType type)
+    : QPixmapData(type, OpenGLClass)
+    , m_renderFbo(0)
+    , m_engine(0)
+    , m_ctx(0)
+    , m_dirty(false)
+    , m_hasFillColor(false)
+    , m_hasAlpha(false)
+    , inLRU(false)
+    , failedToAlloc(false)
+    , inTexturePool(false)
+{
+    setSerialNumber(++qt_gl_pixmap_serial);
+    m_glDevice.setPixmapData(this);
+
+    qt_gl_register_pixmap(this);
+}
+
+QGLPixmapData::~QGLPixmapData()
+{
+    delete m_engine;
+
+    destroyTexture();
+    qt_gl_unregister_pixmap(this);
+}
+
+void QGLPixmapData::destroyTexture()
+{
+    if (inTexturePool) {
+        QGLTexturePool *pool = QGLTexturePool::instance();
+        if (m_texture.id)
+            pool->releaseTexture(this, m_texture.id);
+    } else {
+        if (m_texture.id) {
+            QGLWidget *shareWidget = qt_gl_share_widget();
+            if (shareWidget) {
+                QGLShareContextScope ctx(shareWidget->context());
+                glDeleteTextures(1, &m_texture.id);
+            }
+        }
+    }
+    m_texture.id = 0;
+    inTexturePool = false;
+}
+
+QPixmapData *QGLPixmapData::createCompatiblePixmapData() const
+{
+    return new QGLPixmapData(pixelType());
+}
+
+bool QGLPixmapData::isValid() const
+{
+    return w > 0 && h > 0;
+}
+
+bool QGLPixmapData::isValidContext(const QGLContext *ctx) const
+{
+    if (ctx == m_ctx)
+        return true;
+
+    const QGLContext *share_ctx = qt_gl_share_widget()->context();
+    return ctx == share_ctx || QGLContext::areSharing(ctx, share_ctx);
+}
+
+void QGLPixmapData::resize(int width, int height)
+{
+    if (width == w && height == h)
+        return;
+
+    if (width <= 0 || height <= 0) {
+        width = 0;
+        height = 0;
+    }
+
+    w = width;
+    h = height;
+    is_null = (w <= 0 || h <= 0);
+    d = pixelType() == QPixmapData::PixmapType ? 32 : 1;
+
+    destroyTexture();
+
+    m_source = QImage();
+    m_dirty = isValid();
+    setSerialNumber(++qt_gl_pixmap_serial);
+}
+
+void QGLPixmapData::ensureCreated() const
+{
+    if (!m_dirty)
+        return;
+
+    m_dirty = false;
+
+    QGLShareContextScope ctx(qt_gl_share_widget()->context());
+    m_ctx = ctx;
+
+    const GLenum internal_format = m_hasAlpha ? GL_RGBA : GL_RGB;
+#ifdef QT_OPENGL_ES_2
+    const GLenum external_format = internal_format;
+#else
+    const GLenum external_format = qt_gl_preferredTextureFormat();
+#endif
+    const GLenum target = GL_TEXTURE_2D;
+
+    m_texture.options &= ~QGLContext::MemoryManagedBindOption;
+
+    if (!m_texture.id) {
+        m_texture.id = QGLTexturePool::instance()->createTextureForPixmap(
+                                                                target,
+                                                                0, internal_format,
+                                                                w, h,
+                                                                external_format,
+                                                                GL_UNSIGNED_BYTE,
+                                                                const_cast<QGLPixmapData*>(this));
+        if (!m_texture.id) {
+            failedToAlloc = true;
+            return;
+        }
+        glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
+        glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
+
+        inTexturePool = true;
+    } else if (inTexturePool) {
+        glBindTexture(target, m_texture.id);
+        QGLTexturePool::instance()->useTexture(const_cast<QGLPixmapData*>(this));
+    }
+
+    if (!m_source.isNull() && m_texture.id) {
+        if (external_format == GL_RGB) {
+            const QImage tx = m_source.convertToFormat(QImage::Format_RGB888).mirrored(false, true);
+
+            glBindTexture(target, m_texture.id);
+            glTexSubImage2D(target, 0, 0, 0, w, h, external_format,
+                            GL_UNSIGNED_BYTE, tx.bits());
+        } else {
+            // do byte swizzling ARGB -> RGBA
+            const QImage tx = ctx->d_func()->convertToGLFormat(m_source, true, external_format);
+            glBindTexture(target, m_texture.id);
+            glTexSubImage2D(target, 0, 0, 0, w, h, external_format,
+                            GL_UNSIGNED_BYTE, tx.bits());
+        }
+
+        if (useFramebufferObjects())
+            m_source = QImage();
+    }
+}
+
+
+void QGLPixmapData::fromImage(const QImage &image,
+                              Qt::ImageConversionFlags flags)
+{
+    QImage img = image;
+    createPixmapForImage(img, flags, false);
+}
+
+void QGLPixmapData::fromImageReader(QImageReader *imageReader,
+                                 Qt::ImageConversionFlags flags)
+{
+    QImage image = imageReader->read();
+    if (image.isNull())
+        return;
+
+    createPixmapForImage(image, flags, true);
+}
+
+bool QGLPixmapData::fromFile(const QString &filename, const char *format,
+                             Qt::ImageConversionFlags flags)
+{
+    if (pixelType() == QPixmapData::BitmapType)
+        return QPixmapData::fromFile(filename, format, flags);
+    QFile file(filename);
+    if (file.open(QIODevice::ReadOnly)) {
+        QByteArray data = file.peek(64);
+        bool alpha;
+        if (m_texture.canBindCompressedTexture
+                (data.constData(), data.size(), format, &alpha)) {
+            resize(0, 0);
+            data = file.readAll();
+            file.close();
+            QGLShareContextScope ctx(qt_gl_share_widget()->context());
+            QSize size = m_texture.bindCompressedTexture
+                (data.constData(), data.size(), format);
+            if (!size.isEmpty()) {
+                w = size.width();
+                h = size.height();
+                is_null = false;
+                d = 32;
+                m_hasAlpha = alpha;
+                m_source = QImage();
+                m_dirty = isValid();
+                return true;
+            }
+            return false;
+        }
+    }
+
+    QImage image = QImageReader(filename, format).read();
+    if (image.isNull())
+        return false;
+
+    createPixmapForImage(image, flags, true);
+
+    return !isNull();
+}
+
+bool QGLPixmapData::fromData(const uchar *buffer, uint len, const char *format,
+                             Qt::ImageConversionFlags flags)
+{
+    bool alpha;
+    const char *buf = reinterpret_cast<const char *>(buffer);
+    if (m_texture.canBindCompressedTexture(buf, int(len), format, &alpha)) {
+        resize(0, 0);
+        QGLShareContextScope ctx(qt_gl_share_widget()->context());
+        QSize size = m_texture.bindCompressedTexture(buf, int(len), format);
+        if (!size.isEmpty()) {
+            w = size.width();
+            h = size.height();
+            is_null = false;
+            d = 32;
+            m_hasAlpha = alpha;
+            m_source = QImage();
+            m_dirty = isValid();
+            return true;
+        }
+    }
+
+    QByteArray a = QByteArray::fromRawData(reinterpret_cast<const char *>(buffer), len);
+    QBuffer b(&a);
+    b.open(QIODevice::ReadOnly);
+    QImage image = QImageReader(&b, format).read();
+    if (image.isNull())
+        return false;
+
+    createPixmapForImage(image, flags, true);
+
+    return !isNull();
+}
+
+/*!
+    out-of-place conversion (inPlace == false) will always detach()
+ */
+void QGLPixmapData::createPixmapForImage(QImage &image, Qt::ImageConversionFlags flags, bool inPlace)
+{
+    if (image.size() == QSize(w, h))
+        setSerialNumber(++qt_gl_pixmap_serial);
+
+    resize(image.width(), image.height());
+
+    if (pixelType() == BitmapType) {
+        m_source = image.convertToFormat(QImage::Format_MonoLSB);
+
+    } else {
+        QImage::Format format = QImage::Format_RGB32;
+        if (qApp->desktop()->depth() == 16)
+            format = QImage::Format_RGB16;
+
+        if (image.hasAlphaChannel()
+            && ((flags & Qt::NoOpaqueDetection)
+                || const_cast<QImage &>(image).data_ptr()->checkForAlphaPixels()))
+            format = QImage::Format_ARGB32_Premultiplied;
+
+        if (inPlace && image.data_ptr()->convertInPlace(format, flags)) {
+            m_source = image;
+        } else {
+            m_source = image.convertToFormat(format);
+
+            // convertToFormat won't detach the image if format stays the same.
+            if (image.format() == format)
+                m_source.detach();
+        }
+    }
+
+    m_dirty = true;
+    m_hasFillColor = false;
+
+    m_hasAlpha = m_source.hasAlphaChannel();
+    w = image.width();
+    h = image.height();
+    is_null = (w <= 0 || h <= 0);
+    d = m_source.depth();
+
+    destroyTexture();
+}
+
+bool QGLPixmapData::scroll(int dx, int dy, const QRect &rect)
+{
+    Q_UNUSED(dx);
+    Q_UNUSED(dy);
+    Q_UNUSED(rect);
+    return false;
+}
+
+void QGLPixmapData::copy(const QPixmapData *data, const QRect &rect)
+{
+    if (data->classId() != QPixmapData::OpenGLClass || !static_cast<const QGLPixmapData *>(data)->useFramebufferObjects()) {
+        QPixmapData::copy(data, rect);
+        return;
+    }
+
+    const QGLPixmapData *other = static_cast<const QGLPixmapData *>(data);
+    if (other->m_renderFbo) {
+        QGLShareContextScope ctx(qt_gl_share_widget()->context());
+
+        resize(rect.width(), rect.height());
+        m_hasAlpha = other->m_hasAlpha;
+        ensureCreated();
+
+        if (!ctx->d_ptr->fbo)
+            glGenFramebuffers(1, &ctx->d_ptr->fbo);
+
+        glBindFramebuffer(GL_DRAW_FRAMEBUFFER_EXT, ctx->d_ptr->fbo);
+        glFramebufferTexture2D(GL_DRAW_FRAMEBUFFER_EXT, GL_COLOR_ATTACHMENT0_EXT,
+                GL_TEXTURE_2D, m_texture.id, 0);
+
+        if (!other->m_renderFbo->isBound())
+            glBindFramebuffer(GL_READ_FRAMEBUFFER_EXT, other->m_renderFbo->handle());
+
+        glDisable(GL_SCISSOR_TEST);
+        if (ctx->d_ptr->active_engine && ctx->d_ptr->active_engine->type() == QPaintEngine::OpenGL2)
+            static_cast<QGL2PaintEngineEx *>(ctx->d_ptr->active_engine)->invalidateState();
+
+        glBlitFramebufferEXT(rect.x(), rect.y(), rect.x() + rect.width(), rect.y() + rect.height(),
+                0, 0, w, h,
+                GL_COLOR_BUFFER_BIT,
+                GL_NEAREST);
+
+        glBindFramebuffer(GL_FRAMEBUFFER_EXT, ctx->d_ptr->current_fbo);
+    } else {
+        QPixmapData::copy(data, rect);
+    }
+}
+
+void QGLPixmapData::fill(const QColor &color)
+{
+    if (!isValid())
+        return;
+
+    bool hasAlpha = color.alpha() != 255;
+    if (hasAlpha && !m_hasAlpha) {
+        if (m_texture.id) {
+            destroyTexture();
+            m_dirty = true;
+        }
+        m_hasAlpha = color.alpha() != 255;
+    }
+
+    if (useFramebufferObjects()) {
+        m_source = QImage();
+        m_hasFillColor = true;
+        m_fillColor = color;
+    } else {
+
+        if (m_source.isNull()) {
+            m_fillColor = color;
+            m_hasFillColor = true;
+
+        } else if (m_source.depth() == 32) {
+            m_source.fill(PREMUL(color.rgba()));
+
+        } else if (m_source.depth() == 1) {
+            if (color == Qt::color1)
+                m_source.fill(1);
+            else
+                m_source.fill(0);
+        }
+    }
+}
+
+bool QGLPixmapData::hasAlphaChannel() const
+{
+    return m_hasAlpha;
+}
+
+QImage QGLPixmapData::fillImage(const QColor &color) const
+{
+    QImage img;
+    if (pixelType() == BitmapType) {
+        img = QImage(w, h, QImage::Format_MonoLSB);
+
+        img.setColorCount(2);
+        img.setColor(0, QColor(Qt::color0).rgba());
+        img.setColor(1, QColor(Qt::color1).rgba());
+
+        if (color == Qt::color1)
+            img.fill(1);
+        else
+            img.fill(0);
+    } else {
+        img = QImage(w, h,
+                m_hasAlpha
+                ? QImage::Format_ARGB32_Premultiplied
+                : QImage::Format_RGB32);
+        img.fill(PREMUL(color.rgba()));
+    }
+    return img;
+}
+
+extern QImage qt_gl_read_texture(const QSize &size, bool alpha_format, bool include_alpha);
+
+QImage QGLPixmapData::toImage() const
+{
+    if (!isValid())
+        return QImage();
+
+    if (m_renderFbo) {
+        copyBackFromRenderFbo(true);
+    } else if (!m_source.isNull()) {
+        QImageData *data = const_cast<QImage &>(m_source).data_ptr();
+        if (data->paintEngine && data->paintEngine->isActive()
+            && data->paintEngine->paintDevice() == &m_source)
+        {
+            return m_source.copy();
+        }
+        return m_source;
+    } else if (m_dirty || m_hasFillColor) {
+        return fillImage(m_fillColor);
+    } else {
+        ensureCreated();
+    }
+
+    QGLShareContextScope ctx(qt_gl_share_widget()->context());
+    glBindTexture(GL_TEXTURE_2D, m_texture.id);
+    return qt_gl_read_texture(QSize(w, h), true, true);
+}
+
+struct TextureBuffer
+{
+    QGLFramebufferObject *fbo;
+    QGL2PaintEngineEx *engine;
+};
+
+Q_GLOBAL_STATIC(QGLFramebufferObjectPool, _qgl_fbo_pool)
+QGLFramebufferObjectPool* qgl_fbo_pool()
+{
+    return _qgl_fbo_pool();
+}
+
+void QGLPixmapData::copyBackFromRenderFbo(bool keepCurrentFboBound) const
+{
+    if (!isValid())
+        return;
+
+    m_hasFillColor = false;
+
+    const QGLContext *share_ctx = qt_gl_share_widget()->context();
+    QGLShareContextScope ctx(share_ctx);
+
+    ensureCreated();
+
+    if (!ctx->d_ptr->fbo)
+        glGenFramebuffers(1, &ctx->d_ptr->fbo);
+
+    glBindFramebuffer(GL_DRAW_FRAMEBUFFER_EXT, ctx->d_ptr->fbo);
+    glFramebufferTexture2D(GL_DRAW_FRAMEBUFFER_EXT, GL_COLOR_ATTACHMENT0_EXT,
+        GL_TEXTURE_2D, m_texture.id, 0);
+
+    const int x0 = 0;
+    const int x1 = w;
+    const int y0 = 0;
+    const int y1 = h;
+
+    if (!m_renderFbo->isBound())
+        glBindFramebuffer(GL_READ_FRAMEBUFFER_EXT, m_renderFbo->handle());
+
+    glDisable(GL_SCISSOR_TEST);
+
+    glBlitFramebufferEXT(x0, y0, x1, y1,
+            x0, y0, x1, y1,
+            GL_COLOR_BUFFER_BIT,
+            GL_NEAREST);
+
+    if (keepCurrentFboBound) {
+        glBindFramebuffer(GL_FRAMEBUFFER_EXT, ctx->d_ptr->current_fbo);
+    } else {
+        glBindFramebuffer(GL_DRAW_FRAMEBUFFER_EXT, m_renderFbo->handle());
+        ctx->d_ptr->current_fbo = m_renderFbo->handle();
+    }
+}
+
+bool QGLPixmapData::useFramebufferObjects() const
+{
+#ifdef Q_OS_SYMBIAN
+    // We don't want to use FBOs on Symbian
+    return false;
+#else
+    return QGLFramebufferObject::hasOpenGLFramebufferObjects()
+           && QGLFramebufferObject::hasOpenGLFramebufferBlit()
+           && qt_gl_preferGL2Engine()
+           && (w * h > 32*32); // avoid overhead of FBOs for small pixmaps
+#endif
+}
+
+QPaintEngine* QGLPixmapData::paintEngine() const
+{
+    if (!isValid())
+        return 0;
+
+    if (m_renderFbo)
+        return m_engine;
+
+    if (useFramebufferObjects()) {
+        extern QGLWidget* qt_gl_share_widget();
+
+        if (!QGLContext::currentContext())
+            qt_gl_share_widget()->makeCurrent();
+        QGLShareContextScope ctx(qt_gl_share_widget()->context());
+
+        QGLFramebufferObjectFormat format;
+        format.setAttachment(QGLFramebufferObject::CombinedDepthStencil);
+        format.setSamples(4);
+        format.setInternalTextureFormat(GLenum(m_hasAlpha ? GL_RGBA : GL_RGB));
+
+        m_renderFbo = qgl_fbo_pool()->acquire(size(), format);
+
+        if (m_renderFbo) {
+            if (!m_engine)
+                m_engine = new QGL2PaintEngineEx;
+            return m_engine;
+        }
+
+        qWarning() << "Failed to create pixmap texture buffer of size " << size() << ", falling back to raster paint engine";
+    }
+
+    // If the application wants to paint into the QPixmap, we first
+    // force it to QImage format and then paint into that.
+    // This is simpler than juggling multiple GL contexts.
+    const_cast<QGLPixmapData *>(this)->forceToImage();
+
+    if (m_hasFillColor) {
+        m_source.fill(PREMUL(m_fillColor.rgba()));
+        m_hasFillColor = false;
+    }
+    return m_source.paintEngine();
+}
+
+extern QRgb qt_gl_convertToGLFormat(QRgb src_pixel, GLenum texture_format);
+
+// If copyBack is true, bind will copy the contents of the render
+// FBO to the texture (which is not bound to the texture, as it's
+// a multisample FBO).
+GLuint QGLPixmapData::bind(bool copyBack) const
+{
+    if (m_renderFbo && copyBack) {
+        copyBackFromRenderFbo(true);
+    } else {
+        ensureCreated();
+    }
+
+    GLuint id = m_texture.id;
+    glBindTexture(GL_TEXTURE_2D, id);
+
+    if (m_hasFillColor) {
+        if (!useFramebufferObjects()) {
+            m_source = QImage(w, h, QImage::Format_ARGB32_Premultiplied);
+            m_source.fill(PREMUL(m_fillColor.rgba()));
+        }
+
+        m_hasFillColor = false;
+
+        GLenum format = qt_gl_preferredTextureFormat();
+        QImage tx(w, h, QImage::Format_ARGB32_Premultiplied);
+        tx.fill(qt_gl_convertToGLFormat(m_fillColor.rgba(), format));
+        glTexSubImage2D(GL_TEXTURE_2D, 0, 0, 0, w, h, format, GL_UNSIGNED_BYTE, tx.bits());
+    }
+
+    return id;
+}
+
+QGLTexture* QGLPixmapData::texture() const
+{
+    return &m_texture;
+}
+
+void QGLPixmapData::detachTextureFromPool()
+{
+    if (inTexturePool) {
+        QGLTexturePool::instance()->detachTexture(this);
+        inTexturePool = false;
+    }
+}
+
+void QGLPixmapData::hibernate()
+{
+    // If the texture was imported (e.g, from an SgImage under Symbian),
+    // then we cannot copy it back to main memory for storage.
+    if (m_texture.id && m_source.isNull())
+        return;
+
+    forceToImage();
+    destroyTexture();
+}
+
+void QGLPixmapData::reclaimTexture()
+{
+    if (!inTexturePool)
+        return;
+    forceToImage();
+    destroyTexture();
+}
+
+Q_GUI_EXPORT int qt_defaultDpiX();
+Q_GUI_EXPORT int qt_defaultDpiY();
+
+int QGLPixmapData::metric(QPaintDevice::PaintDeviceMetric metric) const
+{
+    if (w == 0)
+        return 0;
+
+    switch (metric) {
+    case QPaintDevice::PdmWidth:
+        return w;
+    case QPaintDevice::PdmHeight:
+        return h;
+    case QPaintDevice::PdmNumColors:
+        return 0;
+    case QPaintDevice::PdmDepth:
+        return d;
+    case QPaintDevice::PdmWidthMM:
+        return qRound(w * 25.4 / qt_defaultDpiX());
+    case QPaintDevice::PdmHeightMM:
+        return qRound(h * 25.4 / qt_defaultDpiY());
+    case QPaintDevice::PdmDpiX:
+    case QPaintDevice::PdmPhysicalDpiX:
+        return qt_defaultDpiX();
+    case QPaintDevice::PdmDpiY:
+    case QPaintDevice::PdmPhysicalDpiY:
+        return qt_defaultDpiY();
+    default:
+        qWarning("QGLPixmapData::metric(): Invalid metric");
+        return 0;
+    }
+}
+
+// Force the pixmap data to be backed by some valid data.
+void QGLPixmapData::forceToImage()
+{
+    if (!isValid())
+        return;
+
+    if (m_source.isNull())
+        m_source = QImage(w, h, QImage::Format_ARGB32_Premultiplied);
+
+    m_dirty = true;
+}
+
+QGLPaintDevice *QGLPixmapData::glDevice() const
+{
+    return &m_glDevice;
+}
+
+QT_END_NAMESPACE
diff --git a/src/opengl/qwindowsurface_gl.cpp b/src/opengl/qwindowsurface_gl.cpp
index 0bffbda..340f75a 100644
--- a/src/opengl/qwindowsurface_gl.cpp
+++ b/src/opengl/qwindowsurface_gl.cpp
@@ -181,16 +181,14 @@ QGLGraphicsSystem::QGLGraphicsSystem(bool useX11GL)
 //
 // QGLWindowSurface
 //
-
 class QGLGlobalShareWidget
 {
 public:
-    QGLGlobalShareWidget() : widget(0), initializing(false) {}
+    QGLGlobalShareWidget() : firstPixmap(0), widgetRefCount(0), widget(0), initializing(false) {}
 
     QGLWidget *shareWidget() {
         if (!initializing && !widget && !cleanedUp) {
             initializing = true;
-
             widget = new QGLWidget(QGLFormat(QGL::SingleBuffer | QGL::NoDepthBuffer | QGL::NoStencilBuffer));
             widget->resize(1, 1);
 
@@ -226,6 +224,9 @@ public:
 
     static bool cleanedUp;
 
+    QGLPixmapData *firstPixmap;
+    int widgetRefCount;
+
 private:
     QGLWidget *widget;
     bool initializing;
@@ -256,6 +257,41 @@ void qt_destroy_gl_share_widget()
     _qt_gl_share_widget()->destroy();
 }
 
+void qt_gl_register_pixmap(QGLPixmapData *pd)
+{
+    QGLGlobalShareWidget *shared = _qt_gl_share_widget();
+    pd->next = shared->firstPixmap;
+    pd->prev = 0;
+    if (shared->firstPixmap)
+        shared->firstPixmap->prev = pd;
+    shared->firstPixmap = pd;
+}
+
+void qt_gl_unregister_pixmap(QGLPixmapData *pd)
+{
+    if (pd->next)
+        pd->next->prev = pd->prev;
+    if (pd->prev) {
+        pd->prev->next = pd->next;
+    } else {
+        QGLGlobalShareWidget *shared = _qt_gl_share_widget();
+        if (shared)
+           shared->firstPixmap = pd->next;
+    }
+}
+
+void qt_gl_hibernate_pixmaps()
+{
+    QGLGlobalShareWidget *shared = _qt_gl_share_widget();
+
+    // Scan all QGLPixmapData objects in the system and hibernate them.
+    QGLPixmapData *pd = shared->firstPixmap;
+    while (pd != 0) {
+        pd->hibernate();
+        pd = pd->next;
+    }
+}
+
 struct QGLWindowSurfacePrivate
 {
     QGLFramebufferObject *fbo;
@@ -347,6 +383,27 @@ QGLWindowSurface::~QGLWindowSurface()
     delete d_ptr->pb;
     delete d_ptr->fbo;
     delete d_ptr;
+
+    if (QGLGlobalShareWidget::cleanedUp)
+        return;
+
+    --(_qt_gl_share_widget()->widgetRefCount);
+
+#ifdef QGL_USE_TEXTURE_POOL
+    if (_qt_gl_share_widget()->widgetRefCount <= 0) {
+        // All of the widget window surfaces have been destroyed
+        // but we still have GL pixmaps active.  Ask them to hibernate
+        // to free up GPU resources until a widget is shown again.
+        // This may eventually cause the EGLContext to be destroyed
+        // because nothing in the system needs a context, which will
+        // free up even more GPU resources.
+        qt_gl_hibernate_pixmaps();
+
+        // Destroy the context if necessary.
+        if (!qt_gl_share_widget()->context()->isSharing())
+            qt_destroy_gl_share_widget();
+    }
+#endif
 }
 
 void QGLWindowSurface::deleted(QObject *object)
@@ -394,6 +451,9 @@ void QGLWindowSurface::hijackWindow(QWidget *widget)
 
     ctx->create(qt_gl_share_widget()->context());
 
+    if (widget != qt_gl_share_widget())
+        ++(_qt_gl_share_widget()->widgetRefCount);
+
 #ifndef QT_NO_EGL
     static bool checkedForNOKSwapRegion = false;
     static bool haveNOKSwapRegion = false;
@@ -405,9 +465,9 @@ void QGLWindowSurface::hijackWindow(QWidget *widget)
         if (haveNOKSwapRegion)
             qDebug() << "Found EGL_NOK_swap_region2 extension. Using partial updates.";
     }
-
-    if (ctx->d_func()->eglContext->configAttrib(EGL_SWAP_BEHAVIOR) != EGL_BUFFER_PRESERVED &&
-        ! haveNOKSwapRegion)
+    bool swapBehaviourPreserved = (ctx->d_func()->eglContext->configAttrib(EGL_SWAP_BEHAVIOR)
+                        || (ctx->d_func()->eglContext->configAttrib(EGL_SURFACE_TYPE)&EGL_SWAP_BEHAVIOR_PRESERVED_BIT));
+    if (!swapBehaviourPreserved && !haveNOKSwapRegion)
         setPartialUpdateSupport(false); // Force full-screen updates
     else
         setPartialUpdateSupport(true);
@@ -421,7 +481,9 @@ void QGLWindowSurface::hijackWindow(QWidget *widget)
 
     voidPtr = &widgetPrivate->extraData()->glContext;
     d_ptr->contexts << ctxPtr;
+#ifndef Q_OS_SYMBIAN
     qDebug() << "hijackWindow() context created for" << widget << d_ptr->contexts.size();
+#endif
 }
 
 QGLContext *QGLWindowSurface::context() const
@@ -908,8 +970,9 @@ void QGLWindowSurface::updateGeometry() {
     if (d_ptr->destructive_swap_buffers)
         initializeOffscreenTexture(surfSize);
 #endif
-
-    qDebug() << "QGLWindowSurface: Using plain widget as window surface" << this;;
+#ifndef Q_OS_SYMBIAN
+    qDebug() << "QGLWindowSurface: Using plain widget as window surface" << this;
+#endif
     d_ptr->ctx = ctx;
     d_ptr->ctx->d_ptr->internal_context = true;
 }