File indexing completed on 2024-05-05 17:42:26

 /*
     SPDX-FileCopyrightText: 2016 David Edmundson <davidedmundson@kde.org>
     SPDX-FileCopyrightText: 2020 Piotr Henryk Dabrowski <phd@phd.re>
     SPDX-FileCopyrightText: 2021 David Redondo <kde@david-redondo.de>
 
     SPDX-License-Identifier: LGPL-2.0-or-later
 */
 
 #include "renderersettings.h"
 
 #include <QGuiApplication>
 #include <QLibraryInfo>
 #include <QOffscreenSurface>
 #include <QOpenGLContext>
 #include <QOpenGLFunctions>
 #include <QQuickWindow>
 #include <QSurfaceFormat>
 #include <QVersionNumber>
 
 /**
  * If QtQuick is configured (QQuickWindow::sceneGraphBackend()) to use the OpenGL backend,
  * check if it is supported or otherwise reconfigure QtQuick to fallback to software mode.
  * This function is called by init().
  *
  * @returns true if the selected backend is supported, false on fallback to software mode.
  */
 static bool checkBackend(QOpenGLContext &checkContext)
 {
     if (!QQuickWindow::sceneGraphBackend().isEmpty()) {
         return true; // QtQuick is not configured to use the OpenGL backend
     }
 
     // kwin wayland has it's own QPA, it is unable to create a GL context at this point.
     // KF6 TODO, drop this . The issue will be resolved in future kwin releases.
     QString platformName = qApp->platformName();
     if (platformName == QLatin1String("wayland-org.kde.kwin.qpa")) {
         return true;
     }
 
 #ifdef QT_NO_OPENGL
     bool ok = false;
 #else
     bool ok = checkContext.create();
 #endif
     if (!ok) {
         qWarning("Warning: fallback to QtQuick software backend.");
         QQuickWindow::setSceneGraphBackend(QStringLiteral("software"));
     }
     return ok;
 }
 
 void initializeRendererSessions()
 {
     // This is loaded via Q_COREAPP_STARTUP_FUNCTION
 
     // Due to a quirk this gets called twice, see QTBUG-54479
 
     // The order of events is:
     // Q*Application constructor starts
     // We load the QPA
     // We load the QPT (The first arguably incorrect invocation triggers)
     // QPA gets initalised
     // QCoreApplication constructor ends
     // Second (correct) invocation
     // it's important that we run after the QPA is initalised'
 
     static bool firstCall = true;
     if (firstCall) {
         firstCall = false;
         return;
     }
 
     PlasmaQtQuickSettings::RendererSettings s;
     QOpenGLContext checkContext;
     if (!s.sceneGraphBackend().isEmpty()) {
         QQuickWindow::setSceneGraphBackend(s.sceneGraphBackend());
     } else {
         QQuickWindow::setSceneGraphBackend(QStringLiteral(""));
         checkBackend(checkContext);
     }
 
     if (!qEnvironmentVariableIsSet("QSG_RENDER_LOOP")) {
         if (!s.renderLoop().isEmpty()) {
             qputenv("QSG_RENDER_LOOP", s.renderLoop().toLatin1());
         } else if (QGuiApplication::platformName() == QLatin1String("wayland")) {
 #if QT_CONFIG(opengl)
             // Workaround for Bug 432062 / QTBUG-95817
             QOffscreenSurface surface;
             surface.create();
             if (checkContext.makeCurrent(&surface)) {
                 const char *vendor = reinterpret_cast<const char *>(checkContext.functions()->glGetString(GL_VENDOR));
                 if (qstrcmp(vendor, "NVIDIA Corporation") == 0) {
                     // Otherwise Qt Quick Windows break when resized
                     qputenv("QSG_RENDER_LOOP", "basic");
                 }
             }
 #endif
         }
     }
 }
 
 // Because this file gets loaded in the platform plugin, the QGuiApplication already exists
 Q_COREAPP_STARTUP_FUNCTION(initializeRendererSessions)