From f3b45ffa6159bc8b7ecfb0578bbb5cb826de1338 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Samuel=20R=C3=B8dal?= Date: Tue, 5 Jun 2012 13:21:55 +0200 Subject: Added OpenGL example and documentation. Change-Id: I2d9d4e52caf0a39fef9648d8a9e83a0c1328f650 Reviewed-by: Paul Olav Tvete --- doc/src/examples/openglwindow.qdoc | 156 +++++++++++++++++++++++++ doc/src/images/openglwindow-example.png | Bin 0 -> 19920 bytes examples/examples.pro | 1 + examples/gui/gui.pro | 2 +- examples/gui/openglwindow/main.cpp | 179 +++++++++++++++++++++++++++++ examples/gui/openglwindow/openglwindow.cpp | 169 +++++++++++++++++++++++++++ examples/gui/openglwindow/openglwindow.h | 83 +++++++++++++ examples/gui/openglwindow/openglwindow.pri | 3 + examples/gui/openglwindow/openglwindow.pro | 7 ++ src/gui/doc/src/qtgui.qdoc | 17 ++- 10 files changed, 612 insertions(+), 5 deletions(-) create mode 100644 doc/src/examples/openglwindow.qdoc create mode 100644 doc/src/images/openglwindow-example.png create mode 100644 examples/gui/openglwindow/main.cpp create mode 100644 examples/gui/openglwindow/openglwindow.cpp create mode 100644 examples/gui/openglwindow/openglwindow.h create mode 100644 examples/gui/openglwindow/openglwindow.pri create mode 100644 examples/gui/openglwindow/openglwindow.pro diff --git a/doc/src/examples/openglwindow.qdoc b/doc/src/examples/openglwindow.qdoc new file mode 100644 index 0000000000..9d93af5154 --- /dev/null +++ b/doc/src/examples/openglwindow.qdoc @@ -0,0 +1,156 @@ +/**************************************************************************** +** +** Copyright (C) 2012 Nokia Corporation and/or its subsidiary(-ies). +** Contact: http://www.qt-project.org/ +** +** This file is part of the documentation of the Qt Toolkit. +** +** $QT_BEGIN_LICENSE:FDL$ +** GNU Free Documentation License +** Alternatively, this file may be used under the terms of the GNU Free +** Documentation License version 1.3 as published by the Free Software +** Foundation and appearing in the file included in the packaging of +** this file. +** +** 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. +** +** +** +** +** +** $QT_END_LICENSE$ +** +****************************************************************************/ + +/*! + \example gui/openglwindow + \title OpenGL Window Example + + This example shows how to create a minimal QWindow based application + for the purpose of using OpenGL. + + \image openglwindow-example.png Screenshot of the OpenGLWindow example + + \section1 OpenGLWindow super class + + Our OpenGLWindow class acts as an API which is then subclassed to do the + actual rendering. It has functions to make a request for render() to be + called, either immediately with renderNow() or as soon as the event loop + has finished processing the current batch of events with renderLater(). + The OpenGLWindow subclass can either reimplement render() for OpenGL based + rendering, or render(QPainter *) for rendering with a QPainter. Use + OpenGLWindow::setAnimating(true) for render() to be called at the vertical + refresh rate, assuming vertical sync is enabled in the underlying OpenGL + drivers. + + In the class that does the OpenGL rendering you will typically want to + inherit from QOpenGLFunctions, as our OpenGLWindow does, in order to get + platform independent access to OpenGL ES 2.0 functions. By inheriting from + QOpenGLFunctions the OpenGL functions it contains will get precedence, and + you will not have to worry about resolving those functions if you want your + application to work with OpenGL as well as OpenGL ES 2.0. + + \snippet gui/openglwindow/openglwindow.h 1 + + The window's surface type must be set to QSurface::OpenGLSurface to + indicate that the window is to be used for OpenGL rendering and not for + rendering raster content with QPainter using a QBackingStore. + + \snippet gui/openglwindow/openglwindow.cpp 1 + + Any OpenGL initialization needed can be done by overriding the initialize() + function, which is called once before the first call to render(), with a + valid current QOpenGLContext. As can be seen in the following code snippet, + the default render(QPainter *) and initialize() implementations are empty, + whereas the default render() implementation initializes a + QOpenGLPaintDevice and then calls into render(QPainter *). + + \snippet gui/openglwindow/openglwindow.cpp 2 + + The renderLater() function simply puts an update request event on + the event loop, which leads to renderNow() being called once the event + gets processed. + + We also call renderNow() when we get an expose event. The exposeEvent() is + the notification to the window that its exposure, meaning visibility, on + the screen has changed. When the expose event is received you can query + QWindow::isExposed() to find out whether or not the window is currently + exposed. Do not render to or call QOpenGLContext::swapBuffers() on a window + before it has received its first expose event, as before then its final + size might be unknown, and in addition what is rendered might not even end + up on the screen. + + \snippet gui/openglwindow/openglwindow.cpp 3 + + In renderNow() we return if we are not currently exposed, in which case + rendering is delayed until we actually get an expose event. If we have not + yet done so, we create the QOpenGLContext with the same QSurfaceFormat as + was set on the OpenGLWindow, and call initialize() for the sake of the sub + class, and initializeOpenGLFunctions() in order for the QOpenGLFunctions + super class to be associated with the correct QOpenGLContext. In any case + we make the context current by calling QOpenGLContext::makeCurrent(), call + render() to do the actual rendering, and finally we schedule for the + rendered contents to be made visible by calling + QOpenGLContext::swapBuffers() with the OpenGLWindow as parameter. + + Once the rendering of a frame using an OpenGL context is initiated by + calling QOpenGLContext::makeCurrent(), giving the surface on which to + render as a parameter, OpenGL commands can be issued. The commands can be + issued either directly by including , which also includes the + system's OpenGL headers, or as by using QOpenGLFunctions, which can + either be inherited from for convenience, or accessed using + QOpenGLContext::functions(). QOpenGLFunctions gives access to all the + OpenGL ES 2.0 level OpenGL calls that are not already standard in both + OpenGL ES 2.0 and desktop OpenGL. For more information about the OpenGL and + OpenGL ES APIs, refer to the official \l{OpenGL Registry} and + \l{Khronos OpenGL ES API Registry}. + + If animation has been enabled with OpenGLWindow::setAnimating(true), we + call renderLater() to put another update request on the event loop. + + \snippet gui/openglwindow/openglwindow.cpp 4 + + Enabling animation also triggers an update request as shown in the + following code snippet. + + \snippet gui/openglwindow/openglwindow.cpp 5 + + \section1 Example OpenGL rendering sub class + + Here we sub class OpenGLWindow to show how to do OpenGL to render a + rotating triangle. By indirectly sub classing QOpenGLFunctions we gain + access to all OpenGL ES 2.0 level functionality. + + \snippet gui/openglwindow/main.cpp 1 + + In our main function we initialize QGuiApplication and instantiate our + TriangleOpenGLWindow. We give it a QSurfaceFormat specifying that we want + four samples of multisample antialiasing, as well as a default geometry. + Since we want to have animation we call the above mentioned setAnimating() + function with an argument of true. + + \snippet gui/openglwindow/main.cpp 2 + + The following code snippet shows the OpenGL shader program used in this + example. The vertex and fragment shaders are relatively simple, doing + vertex transformation and interpolated vertex coloring. + + \snippet gui/openglwindow/main.cpp 3 + + Here is the code that loads the shaders and initializes the shader program + By using QOpenGLShaderProgram instead of raw OpenGL we get the convenience + that strips out the highp, mediump, and lowp qualifiers on desktop OpenGL, + where they are not part of the standard. We store the attribute and uniform + locations in member variables to avoid having to do the location lookup + each frame. + + \snippet gui/openglwindow/main.cpp 4 + + Finally, here is our render() function, where we use OpenGL to set up the + viewport, clear the background, and render a rotating triangle. + + \snippet gui/openglwindow/main.cpp 5 +*/ diff --git a/doc/src/images/openglwindow-example.png b/doc/src/images/openglwindow-example.png new file mode 100644 index 0000000000..63ba4ed2f4 Binary files /dev/null and b/doc/src/images/openglwindow-example.png differ diff --git a/examples/examples.pro b/examples/examples.pro index 29eda7dff5..a0afb5613c 100644 --- a/examples/examples.pro +++ b/examples/examples.pro @@ -2,6 +2,7 @@ TEMPLATE = subdirs CONFIG += no_docs_target SUBDIRS = \ + gui \ network \ threads \ xml \ diff --git a/examples/gui/gui.pro b/examples/gui/gui.pro index 168379b4ea..baf5d7f3f3 100644 --- a/examples/gui/gui.pro +++ b/examples/gui/gui.pro @@ -2,4 +2,4 @@ TEMPLATE = subdirs SUBDIRS += analogclock SUBDIRS += rasterwindow - +SUBDIRS += openglwindow diff --git a/examples/gui/openglwindow/main.cpp b/examples/gui/openglwindow/main.cpp new file mode 100644 index 0000000000..554e54c2e7 --- /dev/null +++ b/examples/gui/openglwindow/main.cpp @@ -0,0 +1,179 @@ +/**************************************************************************** +** +** Copyright (C) 2012 Nokia Corporation and/or its subsidiary(-ies). +** Contact: http://www.qt-project.org/ +** +** This file is part of the documentation of the Qt Toolkit. +** +** $QT_BEGIN_LICENSE:BSD$ +** You may use this file under the terms of the BSD license as follows: +** +** "Redistribution and use in source and binary forms, with or without +** modification, are permitted provided that the following conditions are +** met: +** * Redistributions of source code must retain the above copyright +** notice, this list of conditions and the following disclaimer. +** * Redistributions in binary form must reproduce the above copyright +** notice, this list of conditions and the following disclaimer in +** the documentation and/or other materials provided with the +** distribution. +** * Neither the name of Nokia Corporation and its Subsidiary(-ies) nor +** the names of its contributors may be used to endorse or promote +** products derived from this software without specific prior written +** permission. +** +** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS +** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT +** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR +** A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT +** OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, +** SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT +** LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, +** DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY +** THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT +** (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE +** OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE." +** +** $QT_END_LICENSE$ +** +****************************************************************************/ + +#include "openglwindow.h" + +#include +#include +#include +#include + +#include + +//! [1] +class TriangleWindow : public OpenGLWindow +{ +public: + TriangleWindow(); + + void initialize(); + void render(); + +private: + GLuint loadShader(GLenum type, const char *source); + + GLuint m_posAttr; + GLuint m_colAttr; + GLuint m_matrixUniform; + + QOpenGLShaderProgram *m_program; + int m_frame; +}; + +TriangleWindow::TriangleWindow() + : m_program(0) + , m_frame(0) +{ +} +//! [1] + +//! [2] +int main(int argc, char **argv) +{ + QGuiApplication app(argc, argv); + + QSurfaceFormat format; + format.setSamples(4); + + TriangleWindow window; + window.setFormat(format); + window.resize(640, 480); + window.show(); + + window.setAnimating(true); + + return app.exec(); +} +//! [2] + + +//! [3] +static const char *vertexShaderSource = + "attribute highp vec4 posAttr;\n" + "attribute lowp vec4 colAttr;\n" + "varying lowp vec4 col;\n" + "uniform highp mat4 matrix;\n" + "void main() {\n" + " col = colAttr;\n" + " gl_Position = matrix * posAttr;\n" + "}\n"; + +static const char *fragmentShaderSource = + "varying lowp vec4 col;\n" + "void main() {\n" + " gl_FragColor = col;\n" + "}\n"; +//! [3] + +//! [4] +GLuint TriangleWindow::loadShader(GLenum type, const char *source) +{ + GLuint shader = glCreateShader(type); + glShaderSource(shader, 1, &source, 0); + glCompileShader(shader); + return shader; +} + +void TriangleWindow::initialize() +{ + m_program = new QOpenGLShaderProgram(this); + m_program->addShaderFromSourceCode(QOpenGLShader::Vertex, vertexShaderSource); + m_program->addShaderFromSourceCode(QOpenGLShader::Fragment, fragmentShaderSource); + m_program->link(); + m_posAttr = m_program->attributeLocation("posAttr"); + m_colAttr = m_program->attributeLocation("colAttr"); + m_matrixUniform = m_program->uniformLocation("matrix"); +} +//! [4] + +//! [5] +void TriangleWindow::render() +{ + glViewport(0, 0, width(), height()); + + glClear(GL_COLOR_BUFFER_BIT); + + m_program->bind(); + + QMatrix4x4 matrix; + matrix.perspective(60, 4.0/3.0, 0.1, 100.0); + matrix.translate(0, 0, -2); + matrix.rotate(100.0f * m_frame / screen()->refreshRate(), 0, 1, 0); + + m_program->setUniformValue(m_matrixUniform, matrix); + + GLfloat vertices[] = { + 0.0f, 0.707f, + -0.5f, -0.5f, + 0.5f, -0.5f + }; + + GLfloat colors[] = { + 1.0f, 0.0f, 0.0f, + 0.0f, 1.0f, 0.0f, + 0.0f, 0.0f, 1.0f + }; + + glVertexAttribPointer(m_posAttr, 2, GL_FLOAT, GL_FALSE, 0, vertices); + glVertexAttribPointer(m_colAttr, 3, GL_FLOAT, GL_FALSE, 0, colors); + + glEnableVertexAttribArray(0); + glEnableVertexAttribArray(1); + + glDrawArrays(GL_TRIANGLES, 0, 3); + + glDisableVertexAttribArray(1); + glDisableVertexAttribArray(0); + + m_program->release(); + + ++m_frame; +} +//! [5] diff --git a/examples/gui/openglwindow/openglwindow.cpp b/examples/gui/openglwindow/openglwindow.cpp new file mode 100644 index 0000000000..6a052c32e2 --- /dev/null +++ b/examples/gui/openglwindow/openglwindow.cpp @@ -0,0 +1,169 @@ +/**************************************************************************** +** +** Copyright (C) 2012 Nokia Corporation and/or its subsidiary(-ies). +** Contact: http://www.qt-project.org/ +** +** This file is part of the documentation of the Qt Toolkit. +** +** $QT_BEGIN_LICENSE:BSD$ +** You may use this file under the terms of the BSD license as follows: +** +** "Redistribution and use in source and binary forms, with or without +** modification, are permitted provided that the following conditions are +** met: +** * Redistributions of source code must retain the above copyright +** notice, this list of conditions and the following disclaimer. +** * Redistributions in binary form must reproduce the above copyright +** notice, this list of conditions and the following disclaimer in +** the documentation and/or other materials provided with the +** distribution. +** * Neither the name of Nokia Corporation and its Subsidiary(-ies) nor +** the names of its contributors may be used to endorse or promote +** products derived from this software without specific prior written +** permission. +** +** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS +** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT +** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR +** A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT +** OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, +** SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT +** LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, +** DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY +** THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT +** (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE +** OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE." +** +** $QT_END_LICENSE$ +** +****************************************************************************/ + +#include "openglwindow.h" + +#include + +#include +#include +#include + +//! [1] +OpenGLWindow::OpenGLWindow(QWindow *parent) + : QWindow(parent) + , m_update_pending(false) + , m_animating(false) + , m_context(0) + , m_device(0) +{ + setSurfaceType(QWindow::OpenGLSurface); +} +//! [1] + +OpenGLWindow::~OpenGLWindow() +{ + delete m_device; +} +//! [2] +void OpenGLWindow::render(QPainter *painter) +{ + Q_UNUSED(painter); +} + +void OpenGLWindow::initialize() +{ +} + +void OpenGLWindow::render() +{ + if (!m_device) + m_device = new QOpenGLPaintDevice; + + glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT | GL_STENCIL_BUFFER_BIT); + + m_device->setSize(size()); + + QPainter painter(m_device); + render(&painter); +} +//! [2] + +//! [3] +void OpenGLWindow::renderLater() +{ + if (!m_update_pending) { + m_update_pending = true; + QCoreApplication::postEvent(this, new QEvent(QEvent::UpdateRequest)); + } +} + +bool OpenGLWindow::event(QEvent *event) +{ + switch (event->type()) { + case QEvent::UpdateRequest: + renderNow(); + return true; + default: + return QWindow::event(event); + } +} + +void OpenGLWindow::exposeEvent(QExposeEvent *event) +{ + Q_UNUSED(event); + + if (isExposed()) + renderNow(); +} + +void OpenGLWindow::resizeEvent(QResizeEvent *event) +{ + Q_UNUSED(event); + + if (isExposed()) + renderNow(); +} +//! [3] + +//! [4] +void OpenGLWindow::renderNow() +{ + if (!isExposed()) + return; + + m_update_pending = false; + + bool needsInitialize = false; + + if (!m_context) { + m_context = new QOpenGLContext(this); + m_context->setFormat(requestedFormat()); + m_context->create(); + + needsInitialize = true; + } + + m_context->makeCurrent(this); + + if (needsInitialize) { + initializeOpenGLFunctions(); + initialize(); + } + + render(); + + m_context->swapBuffers(this); + + if (m_animating) + renderLater(); +} +//! [4] + +//! [5] +void OpenGLWindow::setAnimating(bool animating) +{ + m_animating = animating; + + if (animating) + renderLater(); +} +//! [5] + diff --git a/examples/gui/openglwindow/openglwindow.h b/examples/gui/openglwindow/openglwindow.h new file mode 100644 index 0000000000..aae797b680 --- /dev/null +++ b/examples/gui/openglwindow/openglwindow.h @@ -0,0 +1,83 @@ +/**************************************************************************** +** +** Copyright (C) 2012 Nokia Corporation and/or its subsidiary(-ies). +** Contact: http://www.qt-project.org/ +** +** This file is part of the documentation of the Qt Toolkit. +** +** $QT_BEGIN_LICENSE:BSD$ +** You may use this file under the terms of the BSD license as follows: +** +** "Redistribution and use in source and binary forms, with or without +** modification, are permitted provided that the following conditions are +** met: +** * Redistributions of source code must retain the above copyright +** notice, this list of conditions and the following disclaimer. +** * Redistributions in binary form must reproduce the above copyright +** notice, this list of conditions and the following disclaimer in +** the documentation and/or other materials provided with the +** distribution. +** * Neither the name of Nokia Corporation and its Subsidiary(-ies) nor +** the names of its contributors may be used to endorse or promote +** products derived from this software without specific prior written +** permission. +** +** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS +** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT +** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR +** A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT +** OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, +** SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT +** LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, +** DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY +** THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT +** (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE +** OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE." +** +** $QT_END_LICENSE$ +** +****************************************************************************/ + +#include +#include + +QT_BEGIN_NAMESPACE +class QPainter; +class QOpenGLContext; +class QOpenGLPaintDevice; +QT_END_NAMESPACE + +//! [1] +class OpenGLWindow : public QWindow, protected QOpenGLFunctions +{ + Q_OBJECT +public: + explicit OpenGLWindow(QWindow *parent = 0); + ~OpenGLWindow(); + + virtual void render(QPainter *painter); + virtual void render(); + + virtual void initialize(); + + void setAnimating(bool animating); + +public slots: + void renderLater(); + void renderNow(); + +protected: + bool event(QEvent *event); + + void exposeEvent(QExposeEvent *event); + void resizeEvent(QResizeEvent *event); + +private: + bool m_update_pending; + bool m_animating; + + QOpenGLContext *m_context; + QOpenGLPaintDevice *m_device; +}; +//! [1] + diff --git a/examples/gui/openglwindow/openglwindow.pri b/examples/gui/openglwindow/openglwindow.pri new file mode 100644 index 0000000000..45b0b0cd29 --- /dev/null +++ b/examples/gui/openglwindow/openglwindow.pri @@ -0,0 +1,3 @@ +INCLUDEPATH += $$PWD +SOURCES += $$PWD/openglwindow.cpp +HEADERS += $$PWD/openglwindow.h diff --git a/examples/gui/openglwindow/openglwindow.pro b/examples/gui/openglwindow/openglwindow.pro new file mode 100644 index 0000000000..c6b3f3c48a --- /dev/null +++ b/examples/gui/openglwindow/openglwindow.pro @@ -0,0 +1,7 @@ +include(openglwindow.pri) + +OTHER_FILES += \ + openglwindow.pri + +SOURCES += \ + main.cpp diff --git a/src/gui/doc/src/qtgui.qdoc b/src/gui/doc/src/qtgui.qdoc index 0421b172cf..41cdfc4b3d 100644 --- a/src/gui/doc/src/qtgui.qdoc +++ b/src/gui/doc/src/qtgui.qdoc @@ -114,10 +114,19 @@ QWindow supports rendering using desktop OpenGL, OpenGL ES 1.1 and OpenGL ES 2.0, depending on what the platform supports. OpenGL rendering is enabled by setting the QWindow's surface type to - QSurface::OpenGLSurface, then creating a QOpenGLContext to manage - the native OpenGL context. - - For more information, see \l {OpenGL Enablers}. + QSurface::OpenGLSurface, choosing the format attributes with + QSurfaceFormat, and then creating a QOpenGLContext to manage + the native OpenGL context. In addition, Qt has QOpenGLPaintDevice, + which enables the use of OpenGL accelerated QPainter rendering, as well as + convenience classes that simplify the writing of OpenGL code and hides the + complexities of extension handling and the differences between OpenGL ES 2 + and desktop OpenGL. The convenience classes include QOpenGLFunctions that + lets an application use all the OpenGL ES 2 functions on desktop OpenGL + without having to manually resolve the OpenGL function pointers and some + classes that wrap native OpenGL resources in a simpler Qt API: + QOpenGLBuffer, QOpenGLFramebufferObject, and QOpenGLShaderProgram. + + For more information, see the \l {OpenGL Window Example}. The Qt GUI module also contains a few math classes to aid with the most common mathmatical operations related to 3D graphics. These -- cgit v1.2.3