1 files changed, 199 insertions, 0 deletions
diff --git a/src/widgets/doc/snippets/code/doc_gui_widgets_qopenglwidget.cpp b/src/widgets/doc/snippets/code/doc_gui_widgets_qopenglwidget.cpp
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@@ -0,0 +1,199 @@
+/****************************************************************************
+**
+** Copyright (C) 2014 Digia Plc and/or its subsidiary(-ies).
+** Contact: http://www.qt-project.org/legal
+**
+** 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 Digia Plc 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."
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+//! [0]
+class MyGLWidget : public QOpenGLWidget
+{
+public:
+    MyGLWidget(QWidget *parent) : QOpenGLWidget(parent) { }
+
+protected:
+    void initializeGL()
+    {
+        // 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)
+    {
+        // 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()
+    {
+        // Draw the scene:
+        QOpenGLFunctions *f = QOpenGLContext::currentContext()->functions();
+        f->glClear(GL_COLOR_BUFFER_BIT);
+        ...
+    }
+
+};
+//! [0]
+
+//! [1]
+class MyGLWidget : public QOpenGLWidget, protected QOpenGLFunctions
+{
+    ...
+    void initializeGL()
+    {
+        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()
+    {
+        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]