Make hellowindow multi display capable on embedded

Platforms like eglfs allow a single window per screen. Thus the behavior of
--multiple is not suitable since it tries to open multiple windows on the
primary screen. Instead, introduce --multiscreen.

Add also --timeout to quit the app after 10 seconds. This is essential on
platforms that do not have windows with decorations that can be used to
close windows.

With eglfs' kms/drm hooks, starting with --multiscreen will now show a
rotating logo on all connected displays, with some random background color.

Change-Id: I53f2651f05620e752c289038a9b3ff4508273173
Reviewed-by: Louai Al-Khanji <louai.al-khanji@digia.com>
Reviewed-by: Andy Nichols <andy.nichols@digia.com>

examples/opengl/hellowindow/hellowindow.cpp

@@ -56,9 +56,14 @@ Renderer::Renderer(const QSurfaceFormat &format, Renderer *share, QScreen *scree
     if (share)
         m_context->setShareContext(share->m_context);
     m_context->create();
+
+    m_backgroundColor = QColor::fromRgbF(0.1f, 0.1f, 0.2f, 1.0f);
+    m_backgroundColor.setRed(qrand() % 64);
+    m_backgroundColor.setGreen(qrand() % 128);
+    m_backgroundColor.setBlue(qrand() % 256);
 }
 
-HelloWindow::HelloWindow(const QSharedPointer<Renderer> &renderer)
+HelloWindow::HelloWindow(const QSharedPointer<Renderer> &renderer, QScreen *screen)
     : m_colorIndex(0), m_renderer(renderer)
 {
     setSurfaceType(QWindow::OpenGLSurface);
@@ -67,6 +72,8 @@ HelloWindow::HelloWindow(const QSharedPointer<Renderer> &renderer)
     setGeometry(QRect(10, 10, 640, 480));
 
     setFormat(renderer->format());
+    if (screen)
+        setScreen(screen);
 
     create();
 
@@ -147,7 +154,7 @@ void Renderer::render()
     f->glViewport(0, 0, viewSize.width() * surface->devicePixelRatio(), viewSize.height() * surface->devicePixelRatio());
     f->glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
 
-    f->glClearColor(0.1f, 0.1f, 0.2f, 1.0f);
+    f->glClearColor(m_backgroundColor.redF(), m_backgroundColor.greenF(), m_backgroundColor.blueF(), m_backgroundColor.alphaF());
     f->glFrontFace(GL_CW);
     f->glCullFace(GL_FRONT);
     f->glEnable(GL_CULL_FACE);
@@ -180,8 +187,13 @@ void Renderer::render()
     QTimer::singleShot(0, this, SLOT(render()));
 }
 
+Q_GLOBAL_STATIC(QMutex, initMutex)
+
 void Renderer::initialize()
 {
+    // Threaded shader compilation can confuse some drivers. Avoid it.
+    QMutexLocker lock(initMutex());
+
     QOpenGLShader *vshader = new QOpenGLShader(QOpenGLShader::Vertex, this);
     vshader->compileSourceCode(
         "attribute highp vec4 vertex;"

examples/opengl/hellowindow/hellowindow.h

@@ -90,12 +90,14 @@ private:
     int m_currentWindow;
 
     QMutex m_windowLock;
+
+    QColor m_backgroundColor;
 };
 
 class HelloWindow : public QWindow
 {
 public:
-    explicit HelloWindow(const QSharedPointer<Renderer> &renderer);
+    explicit HelloWindow(const QSharedPointer<Renderer> &renderer, QScreen *screen = 0);
 
     QColor color() const;
     void updateColor();

examples/opengl/hellowindow/main.cpp

@@ -50,7 +50,9 @@ int main(int argc, char *argv[])
 {
     QGuiApplication app(argc, argv);
 
+    // Some platforms can only have one window per screen. Therefore we need to differentiate.
     const bool multipleWindows = QGuiApplication::arguments().contains(QStringLiteral("--multiple"));
+    const bool multipleScreens = QGuiApplication::arguments().contains(QStringLiteral("--multiscreen"));
 
     QScreen *screen = QGuiApplication::primaryScreen();
 
@@ -93,12 +95,13 @@ int main(int argc, char *argv[])
         windowC->setTitle(QStringLiteral("Thread B - Context B"));
         windowC->setVisible(true);
         windows.prepend(windowC);
-
+    }
+    if (multipleScreens) {
         for (int i = 1; i < QGuiApplication::screens().size(); ++i) {
             QScreen *screen = QGuiApplication::screens().at(i);
             QSharedPointer<Renderer> renderer(new Renderer(format, rendererA.data(), screen));
 
-            renderThread = new QThread;
+            QThread *renderThread = new QThread;
             renderer->moveToThread(renderThread);
             renderThreads.prepend(renderThread);
 
@@ -107,8 +110,7 @@ int main(int argc, char *argv[])
 
             QSize windowSize = screenGeometry.size() * 0.8;
 
-            HelloWindow *window = new HelloWindow(renderer);
-            window->setScreen(screen);
+            HelloWindow *window = new HelloWindow(renderer, screen);
             window->setGeometry(QRect(center, windowSize).translated(-windowSize.width() / 2, -windowSize.height() / 2));
 
             QChar id = QChar('B' + i);
@@ -123,10 +125,16 @@ int main(int argc, char *argv[])
         renderThreads.at(i)->start();
     }
 
+    // Quit after 10 seconds. For platforms that do not have windows that are closeable.
+    if (QCoreApplication::arguments().contains(QStringLiteral("--timeout")))
+        QTimer::singleShot(10000, qGuiApp, SLOT(quit()));
+
     const int exitValue = app.exec();
 
-    for (int i = 0; i < renderThreads.size(); ++i)
+    for (int i = 0; i < renderThreads.size(); ++i) {
+        renderThreads.at(i)->quit(); // some platforms may not have windows to close so ensure quit()
         renderThreads.at(i)->wait();
+    }
 
     qDeleteAll(windows);
     qDeleteAll(renderThreads);