qt 6.5.1 original

examples/opengl/contextinfo/CMakeLists.txt

@@ -0,0 +1,39 @@
+# Copyright (C) 2022 The Qt Company Ltd.
+# SPDX-License-Identifier: BSD-3-Clause
+
+cmake_minimum_required(VERSION 3.16)
+project(contextinfo LANGUAGES CXX)
+
+if(NOT DEFINED INSTALL_EXAMPLESDIR)
+    set(INSTALL_EXAMPLESDIR "examples")
+endif()
+
+set(INSTALL_EXAMPLEDIR "${INSTALL_EXAMPLESDIR}/opengl/contextinfo")
+
+find_package(Qt6 REQUIRED COMPONENTS Core Gui OpenGL Widgets)
+
+qt_standard_project_setup()
+
+qt_add_executable(contextinfo
+    main.cpp
+    renderwindow.cpp renderwindow.h
+    widget.cpp widget.h
+)
+
+set_target_properties(contextinfo PROPERTIES
+    WIN32_EXECUTABLE TRUE
+    MACOSX_BUNDLE TRUE
+)
+
+target_link_libraries(contextinfo PRIVATE
+    Qt6::Core
+    Qt6::Gui
+    Qt6::OpenGL
+    Qt6::Widgets
+)
+
+install(TARGETS contextinfo
+    RUNTIME DESTINATION "${INSTALL_EXAMPLEDIR}"
+    BUNDLE DESTINATION "${INSTALL_EXAMPLEDIR}"
+    LIBRARY DESTINATION "${INSTALL_EXAMPLEDIR}"
+)

examples/opengl/contextinfo/contextinfo.pro

@@ -0,0 +1,14 @@
+TEMPLATE = app
+QT += widgets opengl
+requires(qtConfig(filedialog))
+
+SOURCES += main.cpp \
+           widget.cpp \
+           renderwindow.cpp
+
+HEADERS += widget.h \
+           renderwindow.h
+
+# install
+target.path = $$[QT_INSTALL_EXAMPLES]/opengl/contextinfo
+INSTALLS += target

examples/opengl/contextinfo/main.cpp

@@ -0,0 +1,25 @@
+// Copyright (C) 2016 The Qt Company Ltd.
+// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR BSD-3-Clause
+
+#include <QApplication>
+#include "widget.h"
+
+int main(int argc, char **argv)
+{
+    for (int i = 1; i < argc; ++i) {
+        if (!qstrcmp(argv[i], "-g"))
+            QCoreApplication::setAttribute(Qt::AA_UseOpenGLES);
+        else if (!qstrcmp(argv[i], "-s"))
+            QCoreApplication::setAttribute(Qt::AA_UseSoftwareOpenGL);
+        else if (!qstrcmp(argv[i], "-d"))
+            QCoreApplication::setAttribute(Qt::AA_UseDesktopOpenGL);
+    }
+
+    QApplication app(argc, argv);
+
+    Widget w;
+    w.resize(700, 800);
+    w.show();
+
+    return app.exec();
+}

examples/opengl/contextinfo/renderwindow.cpp

@@ -0,0 +1,191 @@
+// Copyright (C) 2016 The Qt Company Ltd.
+// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR BSD-3-Clause
+
+#include "renderwindow.h"
+#include <QTimer>
+#include <QMatrix4x4>
+#include <QOpenGLContext>
+#include <QtOpenGL/QOpenGLShaderProgram>
+#include <QOpenGLFunctions>
+
+RenderWindow::RenderWindow(const QSurfaceFormat &format)
+    : m_context(nullptr),
+      m_initialized(false),
+      m_forceGLSL110(false),
+      m_angle(0.0f)
+{
+    setSurfaceType(QWindow::OpenGLSurface);
+    setFormat(format);
+    m_context = new QOpenGLContext(this);
+    m_context->setFormat(requestedFormat());
+    if (!m_context->create()) {
+        delete m_context;
+        m_context = nullptr;
+    }
+}
+
+void RenderWindow::exposeEvent(QExposeEvent *)
+{
+    if (isExposed())
+        render();
+}
+
+// ES needs the precision qualifiers.
+// On desktop GL QOpenGLShaderProgram inserts dummy defines for highp/mediump/lowp.
+static const char *vertexShaderSource110 =
+    "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 *fragmentShaderSource110 =
+    "varying lowp vec4 col;\n"
+    "void main() {\n"
+    "   gl_FragColor = col;\n"
+    "}\n";
+
+static const char *vertexShaderSource =
+    "#version 150\n"
+    "in vec4 posAttr;\n"
+    "in vec4 colAttr;\n"
+    "out vec4 col;\n"
+    "uniform mat4 matrix;\n"
+    "void main() {\n"
+    "   col = colAttr;\n"
+    "   gl_Position = matrix * posAttr;\n"
+    "}\n";
+
+static const char *fragmentShaderSource =
+    "#version 150\n"
+    "in vec4 col;\n"
+    "out vec4 fragColor;\n"
+    "void main() {\n"
+    "   fragColor = col;\n"
+    "}\n";
+
+static GLfloat vertices[] = {
+    0.0f, 0.707f,
+    -0.5f, -0.5f,
+    0.5f, -0.5f
+};
+
+static GLfloat colors[] = {
+    1.0f, 0.0f, 0.0f,
+    0.0f, 1.0f, 0.0f,
+    0.0f, 0.0f, 1.0f
+};
+
+void RenderWindow::init()
+{
+    m_program = new QOpenGLShaderProgram(this);
+
+    QSurfaceFormat format = m_context->format();
+    bool useNewStyleShader = format.profile() == QSurfaceFormat::CoreProfile;
+    // Try to handle 3.0 & 3.1 that do not have the core/compatibility profile concept 3.2+ has.
+    // This may still fail since version 150 (3.2) is specified in the sources but it's worth a try.
+    if (format.renderableType() == QSurfaceFormat::OpenGL && format.majorVersion() == 3 && format.minorVersion() <= 1)
+        useNewStyleShader = !format.testOption(QSurfaceFormat::DeprecatedFunctions);
+    if (m_forceGLSL110)
+        useNewStyleShader = false;
+
+    const char *vsrc = useNewStyleShader ? vertexShaderSource : vertexShaderSource110;
+    const char *fsrc = useNewStyleShader ? fragmentShaderSource : fragmentShaderSource110;
+    qDebug("Using version %s shader", useNewStyleShader ? "150" : "110");
+
+    if (!m_program->addShaderFromSourceCode(QOpenGLShader::Vertex, vsrc)) {
+        emit error(m_program->log());
+        return;
+    }
+    if (!m_program->addShaderFromSourceCode(QOpenGLShader::Fragment, fsrc)) {
+        emit error(m_program->log());
+        return;
+    }
+    if (!m_program->link()) {
+        emit error(m_program->log());
+        return;
+    }
+
+    m_posAttr = m_program->attributeLocation("posAttr");
+    m_colAttr = m_program->attributeLocation("colAttr");
+    m_matrixUniform = m_program->uniformLocation("matrix");
+
+    m_vbo.create();
+    m_vbo.bind();
+    m_vbo.allocate(vertices, sizeof(vertices) + sizeof(colors));
+    m_vbo.write(sizeof(vertices), colors, sizeof(colors));
+    m_vbo.release();
+
+    QOpenGLVertexArrayObject::Binder vaoBinder(&m_vao);
+    if (m_vao.isCreated()) // have VAO support, use it
+        setupVertexAttribs();
+}
+
+void RenderWindow::setupVertexAttribs()
+{
+    m_vbo.bind();
+    m_program->setAttributeBuffer(m_posAttr, GL_FLOAT, 0, 2);
+    m_program->setAttributeBuffer(m_colAttr, GL_FLOAT, sizeof(vertices), 3);
+    m_program->enableAttributeArray(m_posAttr);
+    m_program->enableAttributeArray(m_colAttr);
+    m_vbo.release();
+}
+
+bool RenderWindow::event(QEvent *ev)
+{
+    if (ev->type() == QEvent::UpdateRequest)
+        render();
+    return QWindow::event(ev);
+}
+
+void RenderWindow::render()
+{
+    if (!m_context->makeCurrent(this)) {
+        emit error(tr("makeCurrent() failed"));
+        return;
+    }
+
+    QOpenGLFunctions *f = m_context->functions();
+    if (!m_initialized) {
+        m_initialized = true;
+        f->glEnable(GL_DEPTH_TEST);
+        f->glClearColor(0, 0, 0, 1);
+        init();
+        emit ready();
+    }
+
+    if (!m_vbo.isCreated()) // init() failed, don't bother with trying to render
+        return;
+
+    const qreal retinaScale = devicePixelRatio();
+    f->glViewport(0, 0, width() * retinaScale, height() * retinaScale);
+    f->glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
+
+    m_program->bind();
+    QMatrix4x4 matrix;
+    matrix.perspective(60.0f, 4.0f / 3.0f, 0.1f, 100.0f);
+    matrix.translate(0.0f, 0.0f, -2.0f);
+    matrix.rotate(m_angle, 0.0f, 1.0f, 0.0f);
+    m_program->setUniformValue(m_matrixUniform, matrix);
+
+    if (m_vao.isCreated())
+        m_vao.bind();
+    else // no VAO support, set the vertex attribute arrays now
+        setupVertexAttribs();
+
+    f->glDrawArrays(GL_TRIANGLES, 0, 3);
+
+    m_vao.release();
+    m_program->release();
+
+    // swapInterval is 1 by default which means that swapBuffers() will (hopefully) block
+    // and wait for vsync.
+    m_context->swapBuffers(this);
+
+    m_angle += 1.0f;
+
+    requestUpdate();
+}

examples/opengl/contextinfo/renderwindow.h

@@ -0,0 +1,48 @@
+// Copyright (C) 2016 The Qt Company Ltd.
+// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR BSD-3-Clause
+
+#ifndef RENDERWINDOW_H
+#define RENDERWINDOW_H
+
+#include <QWindow>
+#include <QOpenGLVertexArrayObject>
+#include <QOpenGLBuffer>
+
+QT_FORWARD_DECLARE_CLASS(QOpenGLContext)
+QT_FORWARD_DECLARE_CLASS(QOpenGLShaderProgram)
+
+class RenderWindow : public QWindow
+{
+    Q_OBJECT
+
+public:
+    RenderWindow(const QSurfaceFormat &format);
+    QOpenGLContext *context() { return m_context; }
+    void exposeEvent(QExposeEvent *) override;
+    void setForceGLSL110(bool enable) { m_forceGLSL110 = enable; }
+
+signals:
+    void ready();
+    void error(const QString &msg);
+
+protected:
+    bool event(QEvent *ev) override;
+
+private slots:
+    void render();
+
+private:
+    void init();
+    void setupVertexAttribs();
+
+    QOpenGLContext *m_context;
+    bool m_initialized;
+    bool m_forceGLSL110;
+    QOpenGLShaderProgram *m_program;
+    int m_posAttr, m_colAttr, m_matrixUniform;
+    QOpenGLVertexArrayObject m_vao;
+    QOpenGLBuffer m_vbo;
+    float m_angle;
+};
+
+#endif // RENDERWINDOW_H

examples/opengl/contextinfo/widget.cpp

@@ -0,0 +1,360 @@
+// Copyright (C) 2016 The Qt Company Ltd.
+// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR BSD-3-Clause
+
+#include "widget.h"
+#include "renderwindow.h"
+#include <QVBoxLayout>
+#include <QComboBox>
+#include <QGroupBox>
+#include <QRadioButton>
+#include <QCheckBox>
+#include <QHBoxLayout>
+#include <QLabel>
+#include <QList>
+#include <QByteArray>
+#include <QPushButton>
+#include <QTextEdit>
+#include <QSplitter>
+#include <QGuiApplication>
+#include <QSurfaceFormat>
+#include <QOpenGLContext>
+#include <QOpenGLFunctions>
+#include <QDebug>
+#include <QTextStream>
+
+struct Version {
+    const char *str;
+    int major;
+    int minor;
+};
+
+static struct Version versions[] = {
+    { "1.0", 1, 0 },
+    { "1.1", 1, 1 },
+    { "1.2", 1, 2 },
+    { "1.3", 1, 3 },
+    { "1.4", 1, 4 },
+    { "1.5", 1, 5 },
+    { "2.0", 2, 0 },
+    { "2.1", 2, 1 },
+    { "3.0", 3, 0 },
+    { "3.1", 3, 1 },
+    { "3.2", 3, 2 },
+    { "3.3", 3, 3 },
+    { "4.0", 4, 0 },
+    { "4.1", 4, 1 },
+    { "4.2", 4, 2 },
+    { "4.3", 4, 3 },
+    { "4.4", 4, 4 },
+    { "4.5", 4, 5 }
+};
+
+struct Profile {
+    const char *str;
+    QSurfaceFormat::OpenGLContextProfile profile;
+};
+
+static struct Profile profiles[] = {
+    { "none", QSurfaceFormat::NoProfile },
+    { "core", QSurfaceFormat::CoreProfile },
+    { "compatibility", QSurfaceFormat::CompatibilityProfile }
+};
+
+struct Option {
+    const char *str;
+    QSurfaceFormat::FormatOption option;
+};
+
+static struct Option options[] = {
+    { "deprecated functions (not forward compatible)", QSurfaceFormat::DeprecatedFunctions },
+    { "debug context", QSurfaceFormat::DebugContext },
+    { "stereo buffers", QSurfaceFormat::StereoBuffers },
+    // This is not a QSurfaceFormat option but is helpful to determine if the driver
+    // allows compiling old-style shaders with core profile.
+    { "force version 110 shaders", QSurfaceFormat::FormatOption(0) }
+};
+
+struct Renderable {
+    const char *str;
+    QSurfaceFormat::RenderableType renderable;
+};
+
+static struct Renderable renderables[] = {
+    { "default", QSurfaceFormat::DefaultRenderableType },
+#ifndef Q_OS_ANDROID
+    { "OpenGL", QSurfaceFormat::OpenGL },
+#endif
+    { "OpenGL ES", QSurfaceFormat::OpenGLES }
+};
+
+void Widget::addVersions(QLayout *layout)
+{
+    QHBoxLayout *hbox = new QHBoxLayout;
+    hbox->setSpacing(20);
+    QLabel *label = new QLabel(tr("Context &version: "));
+    hbox->addWidget(label);
+    m_version = new QComboBox;
+    m_version->setMinimumWidth(60);
+    label->setBuddy(m_version);
+    hbox->addWidget(m_version);
+    for (size_t i = 0; i < sizeof(versions) / sizeof(Version); ++i) {
+        m_version->addItem(QString::fromLatin1(versions[i].str));
+        if (versions[i].major == 2 && versions[i].minor == 0)
+            m_version->setCurrentIndex(m_version->count() - 1);
+    }
+
+    QPushButton *btn = new QPushButton(tr("Create context"));
+    connect(btn, &QPushButton::clicked, this, &Widget::start);
+    btn->setMinimumSize(120, 40);
+    hbox->addWidget(btn);
+
+    layout->addItem(hbox);
+}
+
+void Widget::addProfiles(QLayout *layout)
+{
+    QGroupBox *groupBox = new QGroupBox(tr("Profile"));
+    QVBoxLayout *vbox = new QVBoxLayout;
+    for (size_t i = 0; i < sizeof(profiles) / sizeof(Profile); ++i)
+        vbox->addWidget(new QRadioButton(QString::fromLatin1(profiles[i].str)));
+    static_cast<QRadioButton *>(vbox->itemAt(0)->widget())->setChecked(true);
+    groupBox->setLayout(vbox);
+    layout->addWidget(groupBox);
+    m_profiles = vbox;
+}
+
+void Widget::addOptions(QLayout *layout)
+{
+    QGroupBox *groupBox = new QGroupBox(tr("Options"));
+    QVBoxLayout *vbox = new QVBoxLayout;
+    for (size_t i = 0; i < sizeof(options) / sizeof(Option); ++i)
+        vbox->addWidget(new QCheckBox(QString::fromLatin1(options[i].str)));
+    groupBox->setLayout(vbox);
+    layout->addWidget(groupBox);
+    m_options = vbox;
+}
+
+void Widget::addRenderableTypes(QLayout *layout)
+{
+    QGroupBox *groupBox = new QGroupBox(tr("Renderable type"));
+    QVBoxLayout *vbox = new QVBoxLayout;
+    for (size_t i = 0; i < sizeof(renderables) / sizeof(Renderable); ++i)
+        vbox->addWidget(new QRadioButton(QString::fromLatin1(renderables[i].str)));
+    static_cast<QRadioButton *>(vbox->itemAt(0)->widget())->setChecked(true);
+    groupBox->setLayout(vbox);
+    layout->addWidget(groupBox);
+    m_renderables = vbox;
+}
+
+void Widget::addRenderWindow()
+{
+    m_renderWindowLayout->addWidget(m_renderWindowContainer);
+}
+
+static QWidget *widgetWithLayout(QLayout *layout)
+{
+    QWidget *w = new QWidget;
+    w->setLayout(layout);
+    return w;
+}
+
+Widget::Widget(QWidget *parent)
+    : QWidget(parent)
+{
+    QVBoxLayout *layout = new QVBoxLayout;
+    QSplitter *vsplit = new QSplitter(Qt::Vertical);
+    layout->addWidget(vsplit);
+
+    QSplitter *hsplit = new QSplitter;
+
+    QVBoxLayout *settingsLayout = new QVBoxLayout;
+    addVersions(settingsLayout);
+    addProfiles(settingsLayout);
+    addOptions(settingsLayout);
+    addRenderableTypes(settingsLayout);
+    hsplit->addWidget(widgetWithLayout(settingsLayout));
+
+    QVBoxLayout *outputLayout = new QVBoxLayout;
+    m_output = new QTextEdit;
+    m_output->setReadOnly(true);
+    outputLayout->addWidget(m_output);
+    m_extensions = new QTextEdit;
+    m_extensions->setReadOnly(true);
+    outputLayout->addWidget(m_extensions);
+    hsplit->addWidget(widgetWithLayout(outputLayout));
+
+    hsplit->setStretchFactor(0, 4);
+    hsplit->setStretchFactor(1, 6);
+    vsplit->addWidget(hsplit);
+
+    m_renderWindowLayout = new QVBoxLayout;
+    vsplit->addWidget(widgetWithLayout(m_renderWindowLayout));
+    vsplit->setStretchFactor(1, 5);
+
+    m_renderWindowContainer = new QWidget;
+    addRenderWindow();
+
+    QString description;
+    QTextStream str(&description);
+    str << "Qt " << QT_VERSION_STR << ' ' << QGuiApplication::platformName();
+    const char *openGlVariables[] =
+        {"QT_ANGLE_PLATFORM", "QT_OPENGL", "QT_OPENGL_BUGLIST", "QT_OPENGL_DLL"};
+    const size_t variableCount = sizeof(openGlVariables) / sizeof(openGlVariables[0]);
+    for (size_t v = 0; v < variableCount; ++v) {
+        if (qEnvironmentVariableIsSet(openGlVariables[v]))
+            str << ' ' << openGlVariables[v] << '=' << qgetenv(openGlVariables[v]);
+    }
+    if (QCoreApplication::testAttribute(Qt::AA_UseOpenGLES))
+        str << " Qt::AA_UseOpenGLES";
+    if (QCoreApplication::testAttribute(Qt::AA_UseSoftwareOpenGL))
+        str << " Qt::AA_UseSoftwareOpenGL";
+    if (QCoreApplication::testAttribute(Qt::AA_UseDesktopOpenGL))
+        str << " Qt::AA_UseDesktopOpenGL";
+    layout->addWidget(new QLabel(description));
+
+    setLayout(layout);
+}
+
+void Widget::start()
+{
+    QSurfaceFormat fmt;
+
+    int idx = m_version->currentIndex();
+    if (idx < 0)
+        return;
+    fmt.setVersion(versions[idx].major, versions[idx].minor);
+
+    for (size_t i = 0; i < sizeof(profiles) / sizeof(Profile); ++i)
+        if (static_cast<QRadioButton *>(m_profiles->itemAt(int(i))->widget())->isChecked()) {
+            fmt.setProfile(profiles[i].profile);
+            break;
+        }
+
+    bool forceGLSL110 = false;
+    for (size_t i = 0; i < sizeof(options) / sizeof(Option); ++i)
+        if (static_cast<QCheckBox *>(m_options->itemAt(int(i))->widget())->isChecked()) {
+            if (options[i].option)
+                fmt.setOption(options[i].option);
+            else if (i == 3)
+                forceGLSL110 = true;
+        }
+
+    for (size_t i = 0; i < sizeof(renderables) / sizeof(Renderable); ++i)
+        if (static_cast<QRadioButton *>(m_renderables->itemAt(int(i))->widget())->isChecked()) {
+            fmt.setRenderableType(renderables[i].renderable);
+            break;
+        }
+
+    // The example rendering will need a depth buffer.
+    fmt.setDepthBufferSize(16);
+
+    m_output->clear();
+    m_extensions->clear();
+    qDebug() << "Requesting surface format" << fmt;
+
+    m_renderWindowLayout->removeWidget(m_renderWindowContainer);
+    delete m_renderWindowContainer;
+
+    RenderWindow *renderWindow = new RenderWindow(fmt);
+    if (!renderWindow->context()) {
+        m_output->append(tr("Failed to create context"));
+        delete renderWindow;
+        m_renderWindowContainer = new QWidget;
+        addRenderWindow();
+        return;
+    }
+    m_surface = renderWindow;
+
+    renderWindow->setForceGLSL110(forceGLSL110);
+    connect(renderWindow, &RenderWindow::ready, this, &Widget::renderWindowReady);
+    connect(renderWindow, &RenderWindow::error, this, &Widget::renderWindowError);
+
+    m_renderWindowContainer = QWidget::createWindowContainer(renderWindow);
+    addRenderWindow();
+}
+
+void Widget::printFormat(const QSurfaceFormat &format)
+{
+    m_output->append(tr("OpenGL version: %1.%2").arg(format.majorVersion()).arg(format.minorVersion()));
+
+    for (size_t i = 0; i < sizeof(profiles) / sizeof(Profile); ++i)
+        if (profiles[i].profile == format.profile()) {
+            m_output->append(tr("Profile: %1").arg(QString::fromLatin1(profiles[i].str)));
+            break;
+        }
+
+    QString opts;
+    for (size_t i = 0; i < sizeof(options) / sizeof(Option); ++i)
+        if (format.testOption(options[i].option))
+            opts += QString::fromLatin1(options[i].str) + QLatin1Char(' ');
+    m_output->append(tr("Options: %1").arg(opts));
+
+    for (size_t i = 0; i < sizeof(renderables) / sizeof(Renderable); ++i)
+        if (renderables[i].renderable == format.renderableType()) {
+            m_output->append(tr("Renderable type: %1").arg(QString::fromLatin1(renderables[i].str)));
+            break;
+        }
+
+    m_output->append(tr("Depth buffer size: %1").arg(QString::number(format.depthBufferSize())));
+    m_output->append(tr("Stencil buffer size: %1").arg(QString::number(format.stencilBufferSize())));
+    m_output->append(tr("Samples: %1").arg(QString::number(format.samples())));
+    m_output->append(tr("Red buffer size: %1").arg(QString::number(format.redBufferSize())));
+    m_output->append(tr("Green buffer size: %1").arg(QString::number(format.greenBufferSize())));
+    m_output->append(tr("Blue buffer size: %1").arg(QString::number(format.blueBufferSize())));
+    m_output->append(tr("Alpha buffer size: %1").arg(QString::number(format.alphaBufferSize())));
+    m_output->append(tr("Swap interval: %1").arg(QString::number(format.swapInterval())));
+}
+
+void Widget::renderWindowReady()
+{
+    QOpenGLContext *context = QOpenGLContext::currentContext();
+    Q_ASSERT(context);
+
+    QString vendor, renderer, version, glslVersion;
+    const GLubyte *p;
+    QOpenGLFunctions *f = context->functions();
+    if ((p = f->glGetString(GL_VENDOR)))
+        vendor = QString::fromLatin1(reinterpret_cast<const char *>(p));
+    if ((p = f->glGetString(GL_RENDERER)))
+        renderer = QString::fromLatin1(reinterpret_cast<const char *>(p));
+    if ((p = f->glGetString(GL_VERSION)))
+        version = QString::fromLatin1(reinterpret_cast<const char *>(p));
+    if ((p = f->glGetString(GL_SHADING_LANGUAGE_VERSION)))
+        glslVersion = QString::fromLatin1(reinterpret_cast<const char *>(p));
+
+    m_output->append(tr("*** Context information ***"));
+    m_output->append(tr("Vendor: %1").arg(vendor));
+    m_output->append(tr("Renderer: %1").arg(renderer));
+    m_output->append(tr("OpenGL version: %1").arg(version));
+    m_output->append(tr("GLSL version: %1").arg(glslVersion));
+
+    m_output->append(tr("\n*** QSurfaceFormat from context ***"));
+    printFormat(context->format());
+
+    m_output->append(tr("\n*** QSurfaceFormat from window surface ***"));
+    printFormat(m_surface->format());
+
+    m_output->append(tr("\n*** Qt build information ***"));
+    const char *gltype[] = { "Desktop", "GLES 2", "GLES 1" };
+    m_output->append(tr("Qt OpenGL configuration: %1")
+                     .arg(QString::fromLatin1(gltype[QOpenGLContext::openGLModuleType()])));
+#if defined(Q_OS_WIN)
+    using namespace QNativeInterface;
+    m_output->append(tr("Qt OpenGL library handle: %1")
+                     .arg(QString::number(qintptr(QWGLContext::openGLModuleHandle()), 16)));
+#endif
+
+    QList<QByteArray> extensionList = context->extensions().values();
+    std::sort(extensionList.begin(), extensionList.end());
+    m_extensions->append(tr("Found %1 extensions:").arg(extensionList.count()));
+    for (const QByteArray &ext : std::as_const(extensionList))
+        m_extensions->append(QString::fromLatin1(ext));
+
+    m_output->moveCursor(QTextCursor::Start);
+    m_extensions->moveCursor(QTextCursor::Start);
+}
+
+void Widget::renderWindowError(const QString &msg)
+{
+    m_output->append(tr("An error has occurred:\n%1").arg(msg));
+}

examples/opengl/contextinfo/widget.h

@@ -0,0 +1,46 @@
+// Copyright (C) 2016 The Qt Company Ltd.
+// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR BSD-3-Clause
+
+#ifndef WIDGET_H
+#define WIDGET_H
+
+#include <QWidget>
+
+QT_FORWARD_DECLARE_CLASS(QComboBox)
+QT_FORWARD_DECLARE_CLASS(QTextEdit)
+QT_FORWARD_DECLARE_CLASS(QVBoxLayout)
+QT_FORWARD_DECLARE_CLASS(QSurfaceFormat)
+QT_FORWARD_DECLARE_CLASS(QSurface)
+
+class Widget : public QWidget
+{
+    Q_OBJECT
+
+public:
+    explicit Widget(QWidget *parent = nullptr);
+
+private slots:
+    void start();
+    void renderWindowReady();
+    void renderWindowError(const QString &msg);
+
+private:
+    void addVersions(QLayout *layout);
+    void addProfiles(QLayout *layout);
+    void addOptions(QLayout *layout);
+    void addRenderableTypes(QLayout *layout);
+    void addRenderWindow();
+    void printFormat(const QSurfaceFormat &format);
+
+    QComboBox *m_version;
+    QLayout *m_profiles;
+    QLayout *m_options;
+    QLayout *m_renderables;
+    QTextEdit *m_output;
+    QTextEdit *m_extensions;
+    QVBoxLayout *m_renderWindowLayout;
+    QWidget *m_renderWindowContainer;
+    QSurface *m_surface;
+};
+
+#endif // WIDGET_H