File indexing completed on 2025-04-27 11:33:01

 /*
     SPDX-FileCopyrightText: 2020 Vlad Zahorodnii <vlad.zahorodnii@kde.org>
 
     SPDX-License-Identifier: GPL-2.0-or-later
 */
 
 #include "x11_standalone_sgivideosyncvsyncmonitor.h"
 #include "x11_standalone_glxconvenience.h"
 #include "x11_standalone_logging.h"
 
 #if QT_VERSION >= QT_VERSION_CHECK(6, 0, 0)
 #include <private/qtx11extras_p.h>
 #else
 #include <QX11Info>
 #endif
 
 namespace KWin
 {
 
 std::unique_ptr<SGIVideoSyncVsyncMonitor> SGIVideoSyncVsyncMonitor::create()
 {
     const char *extensions = glXQueryExtensionsString(QX11Info::display(),
                                                       QX11Info::appScreen());
     if (!strstr(extensions, "GLX_SGI_video_sync")) {
         return nullptr; // GLX_SGI_video_sync is unsupported.
     }
 
     std::unique_ptr<SGIVideoSyncVsyncMonitor> monitor{new SGIVideoSyncVsyncMonitor()};
     if (monitor->isValid()) {
         return monitor;
     } else {
         return nullptr;
     }
 }
 
 SGIVideoSyncVsyncMonitorHelper::SGIVideoSyncVsyncMonitorHelper()
 {
     // Establish a new X11 connection to avoid locking up the main X11 connection.
     m_display = XOpenDisplay(DisplayString(QX11Info::display()));
     if (!m_display) {
         qCDebug(KWIN_X11STANDALONE) << "Failed to establish vsync monitor X11 connection";
         return;
     }
 
     ::Window rootWindow = DefaultRootWindow(m_display);
 
     const int attribs[] = {
         GLX_RENDER_TYPE, GLX_RGBA_BIT,
         GLX_DRAWABLE_TYPE, GLX_WINDOW_BIT,
         0};
 
     GLXFBConfig config = chooseGlxFbConfig(m_display, attribs);
     if (!config) {
         qCDebug(KWIN_X11STANDALONE) << "Couldn't find any suitable FBConfig for vsync monitor";
         return;
     }
 
     XVisualInfo *visualInfo = glXGetVisualFromFBConfig(m_display, config);
     if (!visualInfo) {
         return;
     }
 
     Visual *visual = visualInfo->visual;
     const int depth = visualInfo->depth;
     XFree(visualInfo);
 
     Colormap colormap = XCreateColormap(m_display, rootWindow, visual, AllocNone);
     XSetWindowAttributes attributes;
     attributes.colormap = colormap;
 
     m_dummyWindow = XCreateWindow(m_display, rootWindow, 0, 0, 1, 1, 0, depth,
                                   InputOutput, visual, CWColormap, &attributes);
     XFreeColormap(m_display, colormap);
     if (!m_dummyWindow) {
         qCDebug(KWIN_X11STANDALONE) << "Failed to create a dummy window for vsync monitor";
         return;
     }
 
     m_drawable = glXCreateWindow(m_display, config, m_dummyWindow, nullptr);
     if (!m_drawable) {
         qCDebug(KWIN_X11STANDALONE) << "Failed to create GLXWindow for dummy window";
         return;
     }
 
     m_localContext = glXCreateNewContext(m_display, config, GLX_RGBA_TYPE, 0, true);
     if (!m_localContext) {
         qCDebug(KWIN_X11STANDALONE) << "Failed to create opengl context for vsync monitor";
         return;
     }
 }
 
 SGIVideoSyncVsyncMonitorHelper::~SGIVideoSyncVsyncMonitorHelper()
 {
     if (m_localContext) {
         glXDestroyContext(m_display, m_localContext);
     }
     if (m_drawable) {
         glXDestroyWindow(m_display, m_drawable);
     }
     if (m_dummyWindow) {
         XDestroyWindow(m_display, m_dummyWindow);
     }
     if (m_display) {
         XCloseDisplay(m_display);
     }
 }
 
 bool SGIVideoSyncVsyncMonitorHelper::isValid() const
 {
     return m_display && m_localContext && m_drawable;
 }
 
 void SGIVideoSyncVsyncMonitorHelper::poll()
 {
     if (!glXMakeCurrent(m_display, m_drawable, m_localContext)) {
         qCDebug(KWIN_X11STANDALONE) << "Failed to make vsync monitor OpenGL context current";
         Q_EMIT errorOccurred();
         return;
     }
 
     uint count;
 
     glXGetVideoSyncSGI(&count);
     glXWaitVideoSyncSGI(2, (count + 1) % 2, &count);
 
     // Using monotonic clock is inaccurate, but it's still a pretty good estimate.
     Q_EMIT vblankOccurred(std::chrono::steady_clock::now().time_since_epoch());
 }
 
 SGIVideoSyncVsyncMonitor::SGIVideoSyncVsyncMonitor()
 {
     m_helper.moveToThread(&m_thread);
 
     connect(&m_helper, &SGIVideoSyncVsyncMonitorHelper::errorOccurred,
             this, &SGIVideoSyncVsyncMonitor::errorOccurred);
     connect(&m_helper, &SGIVideoSyncVsyncMonitorHelper::vblankOccurred,
             this, &SGIVideoSyncVsyncMonitor::vblankOccurred);
 
     m_thread.setObjectName(QStringLiteral("vsync event monitor"));
     m_thread.start();
 }
 
 SGIVideoSyncVsyncMonitor::~SGIVideoSyncVsyncMonitor()
 {
     m_thread.quit();
     m_thread.wait();
 }
 
 bool SGIVideoSyncVsyncMonitor::isValid() const
 {
     return m_helper.isValid();
 }
 
 void SGIVideoSyncVsyncMonitor::arm()
 {
     QMetaObject::invokeMethod(&m_helper, &SGIVideoSyncVsyncMonitorHelper::poll);
 }
 
 } // namespace KWin