From 787c99b949b93e7263c53f483ff556dbd9684869 Mon Sep 17 00:00:00 2001
From: Vicki Pfau <vi@endrift.com>
Date: Tue, 21 May 2019 22:32:24 -0700
Subject: [PATCH] Qt: Improve GL syncing

---
 src/platform/qt/CoreController.h | 3 +++
 src/platform/qt/Display.cpp      | 2 +-
 src/platform/qt/DisplayGL.cpp    | 5 +++--
 3 files changed, 7 insertions(+), 3 deletions(-)

diff --git a/src/platform/qt/CoreController.h b/src/platform/qt/CoreController.h
index 59fd37ee5..978421249 100644
--- a/src/platform/qt/CoreController.h
+++ b/src/platform/qt/CoreController.h
@@ -98,6 +98,9 @@ public:
 	void setInputController(InputController*);
 	void setLogger(LogController*);
 
+	bool audioSync() const { return m_audioSync; }
+	bool videoSync() const { return m_videoSync; }
+
 public slots:
 	void start();
 	void stop();
diff --git a/src/platform/qt/Display.cpp b/src/platform/qt/Display.cpp
index ee754c4f0..ed7c1fd38 100644
--- a/src/platform/qt/Display.cpp
+++ b/src/platform/qt/Display.cpp
@@ -20,7 +20,7 @@ Display* Display::create(QWidget* parent) {
 #if defined(BUILD_GL) || defined(BUILD_GLES2) || defined(USE_EPOXY)
 	QSurfaceFormat format;
 	format.setSwapInterval(1);
-	format.setSwapBehavior(QSurfaceFormat::TripleBuffer);
+	format.setSwapBehavior(QSurfaceFormat::SingleBuffer);
 #endif
 
 	switch (s_driver) {
diff --git a/src/platform/qt/DisplayGL.cpp b/src/platform/qt/DisplayGL.cpp
index e0cf146a9..77439874a 100644
--- a/src/platform/qt/DisplayGL.cpp
+++ b/src/platform/qt/DisplayGL.cpp
@@ -264,11 +264,12 @@ PainterGL::PainterGL(VideoProxy* proxy, QWindow* surface, QOpenGLContext* parent
 		if (!painter->m_gl->isValid()) {
 			return;
 		}
+		painter->m_gl->doneCurrent();
+		painter->m_gl->swapBuffers(painter->m_surface);
 		painter->m_gl->makeCurrent(painter->m_surface);
 #if defined(_WIN32) && defined(USE_EPOXY)
 		epoxy_handle_external_wglMakeCurrent();
 #endif
-		painter->m_gl->swapBuffers(painter->m_gl->surface());
 	};
 
 	m_backend->init(m_backend, 0);
@@ -383,7 +384,7 @@ void PainterGL::draw() {
 		m_backend->swap(m_backend);
 		if (!m_delayTimer.isValid()) {
 			m_delayTimer.start();
-		} else if (m_gl->format().swapInterval()) {
+		} else if (m_gl->format().swapInterval() && m_context->videoSync()) {
 			while (m_delayTimer.elapsed() < 15) {
 				QThread::usleep(100);
 			}