From db7ed40e1e0c566d4c6bed53c283327c9d55ce4c Mon Sep 17 00:00:00 2001
From: Georges Basile Stavracas Neto <georges.stavracas@gmail.com>
Date: Thu, 20 Aug 2020 11:58:45 -0300
Subject: [PATCH 20/20] UI: Check for Expose and PlatformSurface events to
 create display

This is a workaround for QWaylandWindow never becoming exposed, or
receiving the QEvent::Expose [1].

[1] https://bugreports.qt.io/browse/QTBUG-86176
---
 UI/qt-display.cpp | 58 +++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 58 insertions(+)

diff --git a/UI/qt-display.cpp b/UI/qt-display.cpp
index b230ab4e..4487d460 100644
--- a/UI/qt-display.cpp
+++ b/UI/qt-display.cpp
@@ -10,6 +10,58 @@
 
 #ifdef ENABLE_WAYLAND
 #include <obs-nix-platform.h>
+
+class SurfaceEventFilter : public QObject {
+	OBSQTDisplay *display;
+	int mTimerId;
+
+public:
+	SurfaceEventFilter(OBSQTDisplay *src) : display(src), mTimerId(0) {}
+
+protected:
+	bool eventFilter(QObject *obj, QEvent *event) override
+	{
+		bool result = QObject::eventFilter(obj, event);
+		QPlatformSurfaceEvent *surfaceEvent;
+
+		switch (event->type()) {
+#if QT_VERSION < QT_VERSION_CHECK(5, 15, 1)
+		case QEvent::PlatformSurface:
+			surfaceEvent =
+				static_cast<QPlatformSurfaceEvent *>(event);
+			if (surfaceEvent->surfaceEventType() !=
+			    QPlatformSurfaceEvent::SurfaceCreated)
+				return result;
+
+			if (display->windowHandle()->isExposed())
+				createOBSDisplay();
+			else
+				mTimerId = startTimer(67); // Arbitrary
+			break;
+#endif
+		case QEvent::Expose:
+			createOBSDisplay();
+			break;
+		default:
+			break;
+		}
+
+		return result;
+	}
+
+	void timerEvent(QTimerEvent *) { createOBSDisplay(true); }
+
+private:
+	void createOBSDisplay(bool force = false)
+	{
+		display->CreateDisplay(force);
+		if (mTimerId > 0) {
+			killTimer(mTimerId);
+			mTimerId = 0;
+		}
+	}
+};
+
 #endif
 
 static inline long long color_to_int(const QColor &color)
@@ -65,6 +117,12 @@ OBSQTDisplay::OBSQTDisplay(QWidget *parent, Qt::WindowFlags flags)
 
 	connect(windowHandle(), &QWindow::visibleChanged, windowVisible);
 	connect(windowHandle(), &QWindow::screenChanged, screenChanged);
+
+#ifdef ENABLE_WAYLAND
+	if (obs_get_nix_platform() == OBS_NIX_PLATFORM_WAYLAND)
+		windowHandle()->installEventFilter(
+			new SurfaceEventFilter(this));
+#endif
 }
 
 QColor OBSQTDisplay::GetDisplayBackgroundColor() const
-- 
2.28.0