1 files changed, 168 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..f2c26e0bb8
--- /dev/null
+++ b/src/opengl/doc/snippets/code/doc_gui_widgets_qopenglwidget.cpp
@@ -0,0 +1,168 @@
+// Copyright (C) 2016 The Qt Company Ltd.
+// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR BSD-3-Clause
+
+//! [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]
+MyGLWidget::~MyGLWidget()
+{
+    cleanup();
+}
+
+void MyGLWidget::initializeGL()
+{
+    ...
+    connect(context(), &QOpenGLContext::aboutToBeDestroyed, this, &MyGLWidget::cleanup);
+}
+
+void MyGLWidget::cleanup()
+{
+    makeCurrent();
+    delete m_texture;
+    m_texture = 0;
+    ...
+    doneCurrent();
+    disconnect(context(), &QOpenGLContext::aboutToBeDestroyed, this, &MyGLWidget::cleanup);
+}
+//! [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]