macOS: Experimental Vulkan support via MoltenVK

Add support for QSurface::VulkanSurface and QVulkanWindow.

Usage:
  1) Build MoltenVK according to instructions
  2) Configure Qt: ./configure -I /path/to/MoltenVK/Package/Release/MoltenVK/include
  3) export QT_VULKAN_LIB=/path/to/MoltenVK/Package/Release/MoltenVK/macOS/libMoltenVK.

Implement support for QSurface::VulkanSurface by enabling
layer mode for QNSView and then creating a CAMetalLayer,
which the MoltenVK translation layer can run on.

MoltenVK provides an implementation of the Vulcan API,
which means that the platform integration is similar
to other platforms: implement a QCocoaVulkanInstance
where we pass the QNSView instance to the vkCreateMacOSSurfaceMVK
Vulkan surface constructor function.

Using Vulkan directly without QVulkanWindow is possible, but not
tested.

We currently load libMoltenVK at run-time and use the
existing QT_VULKAN_LIB environment variable to set its
path. For deployment purposes it would be better to
link against MoltenVK.frameworkm, but this

Task-number: QTBUG-66966
Change-Id: I04ec6289c40b199dca9fed32902b5d2ad4e9c030
Reviewed-by: Morten Johan Sørvig <morten.sorvig@qt.io>

1 files changed, 11 insertions, 0 deletions

diff --git a/src/plugins/platforms/cocoa/qcocoaintegration.h b/src/plugins/platforms/cocoa/qcocoaintegration.h
index 301771fd53..7de7e073de 100644
--- a/src/plugins/platforms/cocoa/qcocoaintegration.h
+++ b/src/plugins/platforms/cocoa/qcocoaintegration.h
@@ -51,6 +51,9 @@
 #include "qcocoadrag.h"
 #include "qcocoaservices.h"
 #include "qcocoakeymapper.h"
+#if QT_CONFIG(vulkan)
+#include "qcocoavulkaninstance.h"
+#endif
 
 #include <QtCore/QScopedPointer>
 #include <qpa/qplatformintegration.h>
@@ -86,6 +89,11 @@ public:
 
     QAbstractEventDispatcher *createEventDispatcher() const override;
 
+#if QT_CONFIG(vulkan)
+    QPlatformVulkanInstance *createPlatformVulkanInstance(QVulkanInstance *instance) const override;
+    QCocoaVulkanInstance *getCocoaVulkanInstance() const;
+#endif
+
     QCoreTextFontDatabase *fontDatabase() const override;
     QCocoaNativeInterface *nativeInterface() const override;
     QPlatformInputContext *inputContext() const override;
@@ -144,6 +152,9 @@ private:
     QScopedPointer<QCocoaServices> mServices;
     QScopedPointer<QCocoaKeyMapper> mKeyboardMapper;
 
+#if QT_CONFIG(vulkan)
+    mutable QCocoaVulkanInstance *mCocoaVulkanInstance = nullptr;
+#endif
     QHash<QWindow *, NSToolbar *> mToolbars;
     QList<QCocoaWindow *> m_popupWindowStack;
 };