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

1 files changed, 241 insertions, 0 deletions

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