Fix GPU compositing (and WebGL) to work with ANGLE on Windows

Given the changes that implement GPU compositing on the UI thread (and
thus only a single thread accesses all OpenGL contexts) it is now
possible to enable GPU compositing to work together with ANGLE, which
did not work before due to ANGLE being thread-unsafe.

This requires a couple of things:
- Enable GPU compositing via kInProcessGPU switch when using ANGLE
- A small fix in GLContextHelper::getEGLDisplay() to return a
  correct "egldisplay "handle
- Improved logic when to pass the kDisableES3GLContext switch
  depending on which OpenGL ES version is requested (2 or 3)
- Adjustments in RenderWidgetHostViewQtDelegateWidget() to set up a
  correct surface format which matches the shared
  context OpenGL ES major version
- A recent enough version of ANGLE (due to bugs calling
  glTexImage2D with an unsupported internal texture format for
  GL_DEPTH_COMPONENT, from inside
  gpu::gles2::IsWebGLDrawBuffersSupported)

By default if no special QSurfaceFormat is set as the default
surface format, using ANGLE will create an OpenGL ES 2 context,
and will thus provide support only for WebGL 1.

To enable OpenGL ES 3 / WebGL 2 support, make sure to set a
default QSurfaceFormat with major version set to 3, and enable
ANGLE either via QT_OPENGL=angle or
QGuiApplication::setAttribute(Qt::AA_UseOpenGLES).

The default surface format must be set before the Q*App instance
is created.

Manual test "webgl" added.

Task-number: QTBUG-53908
Task-number: QTBUG-55604
Task-number: QTBUG-69236
Change-Id: Ic31dfdff1ca22d4689db5cf64126d7d12790aa76
Reviewed-by: Jüri Valdmann <juri.valdmann@qt.io>
Reviewed-by: Allan Sandfeld Jensen <allan.jensen@qt.io>
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>

3 files changed, 192 insertions, 1 deletions

diff --git a/tests/manual/widgets/webgl/main.cpp b/tests/manual/widgets/webgl/main.cpp
new file mode 100644
index 000000000..364eda8b9
--- /dev/null
+++ b/tests/manual/widgets/webgl/main.cpp
@@ -0,0 +1,184 @@
+/****************************************************************************
+**
+** Copyright (C) 2018 The Qt Company Ltd.
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of the QtWebEngine module of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:GPL-EXCEPT$
+** 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.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 3 as published by the Free Software
+** Foundation with exceptions as appearing in the file LICENSE.GPL3-EXCEPT
+** included in the packaging of this file. Please review the following
+** information to ensure the GNU General Public License requirements will
+** be met: https://www.gnu.org/licenses/gpl-3.0.html.
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#include <QtCore/QDebug>
+#include <QtCore/QLoggingCategory>
+#include <QtCore/QOperatingSystemVersion>
+#include <QtGui/QOpenGLContext>
+#include <QtGui/QSurfaceFormat>
+#include <QtWidgets/QApplication>
+#include <QtWidgets/QDesktopWidget>
+#include <QtWidgets/QGroupBox>
+#include <QtWidgets/QHBoxLayout>
+#include <QtWidgets/QMainWindow>
+#include <QtWidgets/QPushButton>
+#include <QtWidgets/QVBoxLayout>
+#include <QtWebEngineWidgets/QWebEngineView>
+
+// Manual test for checking if WebGL (1 or 2) works.
+// Set environment variable QTWEBENGINE_GL_TYPE to one of the following to try and switch
+// the underlying GL implementation (mostly Windows): "desktop", "gles", "gles3", "software".
+
+class MainWindow : public QMainWindow
+{
+    Q_OBJECT
+public:
+    explicit MainWindow(QWidget *parent = nullptr);
+    QSize sizeHint() const;
+
+private:
+    QWebEngineView *view = nullptr;
+};
+
+MainWindow::MainWindow(QWidget *parent) : QMainWindow(parent)
+{
+    QWidget *centralWidget = new QWidget;
+
+    QGroupBox *horizontalGroupBox = new QGroupBox;
+    QHBoxLayout *buttonLayout = new QHBoxLayout;
+    QPushButton *exButton1 = new QPushButton(QStringLiteral("Aquarium (WebGL 1)"));
+    QPushButton *exButton2 = new QPushButton(QStringLiteral("Lots of objects (WebGL 1)"));
+    QPushButton *exButton3 = new QPushButton(QStringLiteral("Instanced triangles (WebGL 2)"));
+
+    buttonLayout->addWidget(exButton1);
+    buttonLayout->addWidget(exButton2);
+    buttonLayout->addWidget(exButton3);
+    horizontalGroupBox->setLayout(buttonLayout);
+
+    const QUrl exUrl1 =
+            QUrl(QStringLiteral(
+                     "http://webglsamples.org/aquarium/aquarium.html"));
+    const QUrl exUrl2 =
+            QUrl(QStringLiteral(
+                     "http://webglsamples.org/lots-o-objects/lots-o-objects-draw-elements.html"));
+    const QUrl exUrl3 =
+            QUrl(QStringLiteral(
+                     "http://webglsamples.org/WebGL2Samples/#transform_feedback_instanced"));
+
+    view = new QWebEngineView;
+    connect(exButton1, &QPushButton::clicked, view, [=](){
+        view->setUrl(exUrl1);
+    });
+    connect(exButton2, &QPushButton::clicked, view, [=](){
+        view->setUrl(exUrl2);
+    });
+    connect(exButton3, &QPushButton::clicked, view, [=](){
+        view->setUrl(exUrl3);
+    });
+
+    QVBoxLayout *centralLayout = new QVBoxLayout;
+    centralLayout->addWidget(horizontalGroupBox);
+    centralLayout->addWidget(view, 1);
+
+    centralWidget->setLayout(centralLayout);
+    setCentralWidget(centralWidget);
+
+    view->setUrl(QUrl(QStringLiteral("http://webglsamples.org/aquarium/aquarium.html")));
+    setWindowTitle(tr("WebGL 1 and 2 examples"));
+}
+
+QSize MainWindow::sizeHint() const
+{
+    const QRect desktopRect = QApplication::desktop()->screenGeometry();
+    const QSize size = desktopRect.size() * qreal(0.9);
+    return size;
+}
+
+bool isWindows()
+{
+    return QOperatingSystemVersion::currentType() == QOperatingSystemVersion::Windows;
+}
+
+// Easy snippets to copy to command line for testing for UNIX only.
+// QTWEBENGINE_GL_TYPE=desktop   ./webgl
+// QTWEBENGINE_GL_TYPE=gles      ./webgl
+// QTWEBENGINE_GL_TYPE=gles3     ./webgl
+// QTWEBENGINE_GL_TYPE=software  ./webgl
+int main(int argc, char *argv[])
+{
+    // Not all options are relevant for all platforms.
+    const QString desktopGL = QStringLiteral("desktop");
+    const QString angle = QStringLiteral("angle"); // Same as gles really, just an alias.
+    const QString gles = QStringLiteral("gles"); // ANGLE on Windows.
+    const QString gles3 = QStringLiteral("gles3"); // ANGLE on Windows.
+    const QString softwareGL = QStringLiteral("software");
+
+    QApplication::setAttribute(Qt::AA_EnableHighDpiScaling);
+    QApplication::setAttribute(Qt::AA_UseHighDpiPixmaps);
+
+    QString glType = qEnvironmentVariable("QTWEBENGINE_GL_TYPE");
+    if (glType.isEmpty()) {
+        if (isWindows())
+            glType = gles3;
+        else
+            glType = desktopGL;
+    }
+
+    if (glType == desktopGL) {
+        QApplication::setAttribute(Qt::AA_UseDesktopOpenGL);
+        qInfo() << QStringLiteral("Trying to use Desktop OpenGL.\n");
+    } else if (glType == gles || glType == gles3 || glType == angle) {
+        QApplication::setAttribute(Qt::AA_UseOpenGLES);
+        if (glType == gles || glType == angle)
+            qInfo() << QStringLiteral("Trying to use OpenGL ES 2.\n");
+        if (glType == gles3)
+            qInfo() << QStringLiteral("Trying to use OpenGL ES 3.\n");
+    } else if (glType == softwareGL) {
+        QApplication::setAttribute(Qt::AA_UseSoftwareOpenGL);
+        qInfo() << QStringLiteral("Trying to use software OpenGL.\n");
+    }
+
+    if (glType == gles3) {
+        // Set OpenGL ES version 3.
+        QSurfaceFormat format;
+        format.setSamples(4);
+        format.setDepthBufferSize(24);
+        format.setStencilBufferSize(8);
+        format.setVersion(3, 0);
+        QSurfaceFormat::setDefaultFormat(format);
+    }
+
+    QApplication a(argc, argv);
+
+    QLoggingCategory::setFilterRules(QStringLiteral("qt.scenegraph.general=true"));
+    QOpenGLContext *globalSharedContext = QOpenGLContext::globalShareContext();
+    qInfo() << "Global OpenGL context format: " << globalSharedContext->format() << "\n";
+
+    MainWindow w;
+
+    // Move middle-ish.
+    const QRect desktopRect = QApplication::desktop()->screenGeometry();
+    const QSize pos = desktopRect.size() * qreal(0.1);
+    w.move(pos.width(), pos.height());
+
+    w.show();
+
+    return a.exec();
+}
+
+#include "main.moc"
diff --git a/tests/manual/widgets/webgl/webgl.pro b/tests/manual/widgets/webgl/webgl.pro
new file mode 100644
index 000000000..9141d0221
--- /dev/null
+++ b/tests/manual/widgets/webgl/webgl.pro
@@ -0,0 +1,6 @@
+TEMPLATE = app
+TARGET = webgl
+QT += core gui widgets webenginewidgets
+CONFIG += c++11
+SOURCES += main.cpp
+
diff --git a/tests/manual/widgets/widgets.pro b/tests/manual/widgets/widgets.pro
index f06d3e1c3..34e88f0e3 100644
--- a/tests/manual/widgets/widgets.pro
+++ b/tests/manual/widgets/widgets.pro
@@ -1,4 +1,5 @@
 TEMPLATE= subdirs
 
 SUBDIRS += \
-    inputmethods
+    inputmethods \
+    webgl