Transfers gpu buffer data to cpu

Added some code to retrieve the data in the gpu back to a cpu pointer
in the opengl helpers.

Added a framegraph node which specifies if any data must be downloaded
from the gpu

Added a flag in the buffer object to specify if the data from that
buffer must be downloaded.

Added a job to send the data back to the frontend.

Added a path in the renderer to download the gpu data.

Task number: QTBUG-57727

Change-Id: I315a9221e5116c7d07f818e00c654fe1901144f4
Reviewed-by: Sean Harmer <sean.harmer@kdab.com>

1 files changed, 75 insertions, 0 deletions

diff --git a/src/render/framegraph/buffercapture_p.h b/src/render/framegraph/buffercapture_p.h
new file mode 100644
index 000000000..d638f35d5
--- /dev/null
+++ b/src/render/framegraph/buffercapture_p.h
@@ -0,0 +1,75 @@
+/****************************************************************************
+**
+** Copyright (C) 2017 Juan José Casafranca
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of the Qt3D 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 BUFFERCAPTURE_P_H
+#define BUFFERCAPTURE_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 <Qt3DRender/private/qbuffercapture_p.h>
+#include <Qt3DRender/private/framegraphnode_p.h>
+
+QT_BEGIN_NAMESPACE
+
+namespace Qt3DRender {
+
+namespace Render {
+
+class Q_AUTOTEST_EXPORT BufferCapture : public FrameGraphNode
+{
+public:
+    BufferCapture();
+};
+
+} //Render
+
+} //Qt3DRender
+
+QT_END_NAMESPACE
+
+#endif // BUFFERCAPTURE_P_H