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Diffstat (limited to 'src/opengl/doc/snippets/code/doc_gui_widgets_qopenglwidget.cpp')
-rw-r--r-- | src/opengl/doc/snippets/code/doc_gui_widgets_qopenglwidget.cpp | 209 |
1 files changed, 209 insertions, 0 deletions
diff --git a/src/opengl/doc/snippets/code/doc_gui_widgets_qopenglwidget.cpp b/src/opengl/doc/snippets/code/doc_gui_widgets_qopenglwidget.cpp new file mode 100644 index 0000000000..633a413b4f --- /dev/null +++ b/src/opengl/doc/snippets/code/doc_gui_widgets_qopenglwidget.cpp @@ -0,0 +1,209 @@ +/**************************************************************************** +** +** Copyright (C) 2016 The Qt Company Ltd. +** Contact: https://www.qt.io/licensing/ +** +** This file is part of the documentation of the Qt Toolkit. +** +** $QT_BEGIN_LICENSE:BSD$ +** 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. +** +** BSD License Usage +** Alternatively, 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 The Qt Company Ltd 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." +** +** $QT_END_LICENSE$ +** +****************************************************************************/ + +//! [0] +class MyGLWidget : public QOpenGLWidget +{ +public: + MyGLWidget(QWidget *parent) : QOpenGLWidget(parent) { } + +protected: + void initializeGL() override + { + // Set up the rendering context, load shaders and other resources, etc.: + QOpenGLFunctions *f = QOpenGLContext::currentContext()->functions(); + f->glClearColor(1.0f, 1.0f, 1.0f, 1.0f); + ... + } + + void resizeGL(int w, int h) override + { + // Update projection matrix and other size related settings: + m_projection.setToIdentity(); + m_projection.perspective(45.0f, w / float(h), 0.01f, 100.0f); + ... + } + + void paintGL() override + { + // Draw the scene: + QOpenGLFunctions *f = QOpenGLContext::currentContext()->functions(); + f->glClear(GL_COLOR_BUFFER_BIT); + ... + } + +}; +//! [0] + +//! [1] +class MyGLWidget : public QOpenGLWidget, protected QOpenGLFunctions +{ + ... + void initializeGL() override + { + initializeOpenGLFunctions(); + glClearColor(...); + ... + } + ... +}; +//! [1] + +//! [2] +QOpenGLWidget *widget = new QOpenGLWidget(parent); +QSurfaceFormat format; +format.setDepthBufferSize(24); +format.setStencilBufferSize(8); +format.setVersion(3, 2); +format.setProfile(QSurfaceFormat::CoreProfile); +widget->setFormat(format); // must be called before the widget or its parent window gets shown +//! [2] + +//! [3] + ... + void paintGL() override + { + QOpenGLFunctions_3_2_Core *f = QOpenGLContext::currentContext()->versionFunctions<QOpenGLFunctions_3_2_Core>(); + ... + f->glDrawArraysInstanced(...); + ... + } + ... +//! [3] + +//! [4] +class MyGLWidget : public QOpenGLWidget +{ + ... + +private: + QOpenGLVertexArrayObject m_vao; + QOpenGLBuffer m_vbo; + QOpenGLShaderProgram *m_program; + QOpenGLShader *m_shader; + QOpenGLTexture *m_texture; +}; + +MyGLWidget::MyGLWidget() + : m_program(0), m_shader(0), m_texture(0) +{ + // No OpenGL resource initialization is done here. +} + +MyGLWidget::~MyGLWidget() +{ + // Make sure the context is current and then explicitly + // destroy all underlying OpenGL resources. + makeCurrent(); + + delete m_texture; + delete m_shader; + delete m_program; + + m_vbo.destroy(); + m_vao.destroy(); + + doneCurrent(); +} + +void MyGLWidget::initializeGL() +{ + m_vao.create(); + if (m_vao.isCreated()) + m_vao.bind(); + + m_vbo.create(); + m_vbo.bind(); + m_vbo.allocate(...); + + m_texture = new QOpenGLTexture(QImage(...)); + + m_shader = new QOpenGLShader(...); + m_program = new QOpenGLShaderProgram(...); + + ... +} +//! [4] + +//! [5] +void MyGLWidget::initializeGL() +{ + // context() and QOpenGLContext::currentContext() are equivalent when called from initializeGL or paintGL. + connect(context(), &QOpenGLContext::aboutToBeDestroyed, this, &MyGLWidget::cleanup); +} + +void MyGLWidget::cleanup() +{ + makeCurrent(); + delete m_texture; + m_texture = 0; + ... + doneCurrent(); +} +//! [5] + +//! [6] +int main(int argc, char **argv) +{ + QApplication app(argc, argv); + + QSurfaceFormat format; + format.setDepthBufferSize(24); + format.setStencilBufferSize(8); + format.setVersion(3, 2); + format.setProfile(QSurfaceFormat::CoreProfile); + QSurfaceFormat::setDefaultFormat(format); + + MyWidget widget; + widget.show(); + + return app.exec(); +} +//! [6] |