Cocoa: Add support for triple-buffered GL contexts

As usual, the requested format may not be available, so clients should
check the actual format to confirm triple-buffering.

Change-Id: Icf073cc9ddf2c912eb5c3ce0ac80d1694d1c56d7
Reviewed-by: Jake Petroules <jake.petroules@qt.io>
Reviewed-by: Laszlo Agocs <laszlo.agocs@qt.io>

1 files changed, 9 insertions, 1 deletions

diff --git a/src/plugins/platforms/cocoa/qcocoaglcontext.mm b/src/plugins/platforms/cocoa/qcocoaglcontext.mm
index 0f9b8b900d..b77ca07141 100644
--- a/src/plugins/platforms/cocoa/qcocoaglcontext.mm
+++ b/src/plugins/platforms/cocoa/qcocoaglcontext.mm
@@ -305,8 +305,16 @@ void QCocoaGLContext::updateSurfaceFormat()
         m_format.setSamples(samples);
 
     int doubleBuffered = -1;
+    int tripleBuffered = -1;
     [pixelFormat getValues:&doubleBuffered forAttribute:NSOpenGLPFADoubleBuffer forVirtualScreen:0];
-    m_format.setSwapBehavior(doubleBuffered == 1 ? QSurfaceFormat::DoubleBuffer : QSurfaceFormat::SingleBuffer);
+    [pixelFormat getValues:&tripleBuffered forAttribute:NSOpenGLPFATripleBuffer forVirtualScreen:0];
+
+    if (tripleBuffered == 1)
+        m_format.setSwapBehavior(QSurfaceFormat::TripleBuffer);
+    else if (doubleBuffered == 1)
+        m_format.setSwapBehavior(QSurfaceFormat::DoubleBuffer);
+    else
+        m_format.setSwapBehavior(QSurfaceFormat::SingleBuffer);
 
     int steroBuffers = -1;
     [pixelFormat getValues:&steroBuffers forAttribute:NSOpenGLPFAStereo forVirtualScreen:0];