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/****************************************************************************
**
** Copyright (C) 2014 Digia Plc
** All rights reserved.
** For any questions to Digia, please use the contact form at
** http://qt.digia.com/
**
** This file is part of Qt Quick 2d Renderer.
**
** Licensees holding valid Qt Enterprise licenses may use this file in
** accordance with the Qt Enterprise License Agreement provided with the
** Software or, alternatively, in accordance with the terms contained in
** a written agreement between you and Digia.
**
** If you have questions regarding the use of this file, please use
** the contact form at http://qt.digia.com/
**
****************************************************************************/
/*!
\page qtquick2drenderer-installation-guide.html
\previouspage index.html
\nextpage qtquick2drenderer-limitations.html
\title Installation Guide
The building of \RENDERER is complicated by the fact that \l{Qt Quick} 2
always requires OpenGL support regardless of whether it is being used or
not. You will need to build Qt with support for OpenGL even if the target
system does not support it. If you have a Qt build that already supports
OpenGL, you can skip to \l {building-renderer}{Building \RENDERER}.
\section1 Providing the OpenGL Dependency
\RENDERER works in such a way that it renders the Qt Quick 2 scene
graph with QPainter, instead of using hardware acceleration via the OpenGL API.
However, Qt Quick 2 still assumes that OpenGL is always available. With
\RENDERER we can avoid making OpenGL calls, but that does not change the
fact that QtQuick 2 requires the OpenGL development headers to be available
at build-time and will link against OpenGL libraries at run-time.
The solution is to provide a dummy OpenGL library and development
headers to build Qt against. In this way you can build Qt with virtual OpenGL
support and get access to the QtQuick 2 APIs. You should have no problems
using \RENDERER provided that you use a platform plugin that does not make calls to
EGL or OpenGL commands, and that you refrain from using APIs that access OpenGL directly.
\section1 How to use the OpenGL Dummy Libraries
The OpenGL dummy libraries provide both headers and shared object files
containing the symbols for both OpenGL and EGL. The headers get copied
into your INCLUDE path, and the shared object files get copied into your LIB
path in both the sysroot, as well as in the target image distributed on the
device. The library that is generated contains all the symbols needed to
link an application as if you had support for OpenGL and EGL. It is important
to make sure that you do not call any of these symbols in your application.
\section2 Prerequisites
Three elements are required:
\list 1
\li Toolchain to cross compile code for your device.
\li Sysroot containing development headers and shared objects to link
against when building applications.
\li Target image intended to be deployed to your device.
\endlist
\section2 How to build the OpenGL Dummy Libraries
Set up your build environment by defining where your compiler and sysroot
are located:
\badcode
export CC=/opt/arm-toolchain/usr/bin/arm-linux-gnueabi-g++
export SYSROOT=/opt/device-name/sysroot/
\endcode
Run the build script inside the client-dummy directory:
\badcode
cd client-dummy
./build-gcc.sh
\endcode
That should generate two files: \c libEGL.so, \c libGLESv2.so
\section2 Installation of Files
Copy the include folder to the /usr/include folder in your sysroot. This
installs the OpenGL/EGL headers:
\badcode
cp -r include/* ${SYSROOT}/usr/include/
\endcode
Copy \c libEGL.so and \c libGLESv2.so to the /usr/lib folder in your sysroot:
\badcode
cp src/lib*.so ${SYSROOT}/usr/lib/
\endcode
Copy the \c libEGL.so and \c libGLESv2.so libraries to the target device image as well.
\section1 Building Qt
When configuring Qt, make sure to append \c {-opengl es2} to your configure arguments.
\target building-renderer
\section1 Building \RENDERER
Build \RENDERER like any other Qt module:
\badcode
qmake
make
make install
\endcode
\section1 Deployment
Now, when you deploy your Qt build to the device, it will depend on the dummy
libs \c libEGL.so and \c libGLESv2.so, but as long as you are using the \RENDERER
plugin you will be able to use Qt Quick 2 without actually making any
OpenGL or EGL calls.
*/
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