3rdparty/ext_qt/0133-HACK-Force-glFinish-in-flushShared-for-ANGLE.patch

0001 From 90eed4735d704a5236741ef48e8d17d11906d40c Mon Sep 17 00:00:00 2001
0002 From: Alvin Wong <alvinhochun@gmail.com>
0003 Date: Tue, 5 Apr 2022 18:49:33 +0800
0004 Subject: [PATCH] HACK: Force glFinish in flushShared for ANGLE
0005
0006 ---
0007  src/gui/opengl/qopenglfunctions.cpp | 31 +++++++++++++++++++++++++++++
0008  1 file changed, 31 insertions(+)
0009
0010 diff --git a/src/gui/opengl/qopenglfunctions.cpp b/src/gui/opengl/qopenglfunctions.cpp
0011 index 92770cb55f..848e706d65 100644
0012 --- a/src/gui/opengl/qopenglfunctions.cpp
0013 +++ b/src/gui/opengl/qopenglfunctions.cpp
0014 @@ -5072,6 +5072,37 @@ void QOpenGLExtensions::flushShared()
0015  {
0016      Q_D(QOpenGLExtensions);
0017
0018 +    if (!d->flushVendorChecked) {
0019 +        static bool forceNoGlFinish = qEnvironmentVariableIntValue("KRITA_QT_NO_GL_FINISH_IN_FLUSH_SHARED") == 1;
0020 +        if (forceNoGlFinish) {
0021 +            d->flushVendorChecked = true;
0022 +            d->flushIsSufficientToSyncContexts = true;
0023 +        } else {
0024 +#ifdef Q_OS_WIN
0025 +            // HACK: Workaround QWidget composing too often and causing performance
0026 +            // drop when using ANGLE by forcing a glFinish. This can be disabled
0027 +            // by explicitly setting `KRITA_QT_NO_GL_FINISH_IN_FLUSH_SHARED=1`.
0028 +            //
0029 +            // FIXME: We ought to fix this issue with a more proper way...
0030 +            //
0031 +            // Note: GL_VENDOR on older ANGLE versions only contained "Google Inc.",
0032 +            // but newer versions also included the native graphics vendor, e.g.
0033 +            // "Google Inc. (Intel)". This changed the outcome of the check from
0034 +            // above. In any case, we should explicitly check for ANGLE and its
0035 +            // D3D backend.
0036 +            const char *renderer = (const char *) glGetString(GL_RENDERER);
0037 +            if (renderer && strstr(renderer, "ANGLE") && strstr(renderer, "Direct3D")) {
0038 +                d->flushVendorChecked = true;
0039 +                d->flushIsSufficientToSyncContexts = false;
0040 +                static bool _callOnce = []() {
0041 +                    qDebug() << "QOpenGLExtensions::flushShared() forcing glFinish for ANGLE";
0042 +                    return true;
0043 +                }();
0044 +                Q_UNUSED(_callOnce)
0045 +            }
0046 +#endif
0047 +        }
0048 +    }
0049      if (!d->flushVendorChecked) {
0050          d->flushVendorChecked = true;
0051          // It is not quite clear if glFlush() is sufficient to synchronize access to
0052 --
0053 2.24.1.windows.2
0054