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, 13 insertions, 0 deletions

diff --git a/src/plugins/platforms/cocoa/qcocoaintegration.mm b/src/plugins/platforms/cocoa/qcocoaintegration.mm
index a4658271bb..ce3a1304b2 100644
--- a/src/plugins/platforms/cocoa/qcocoaintegration.mm
+++ b/src/plugins/platforms/cocoa/qcocoaintegration.mm
@@ -379,6 +379,19 @@ QAbstractEventDispatcher *QCocoaIntegration::createEventDispatcher() const
     return new QCocoaEventDispatcher;
 }
 
+#if QT_CONFIG(vulkan)
+QPlatformVulkanInstance *QCocoaIntegration::createPlatformVulkanInstance(QVulkanInstance *instance) const
+{
+    mCocoaVulkanInstance = new QCocoaVulkanInstance(instance);
+    return mCocoaVulkanInstance;
+}
+
+QCocoaVulkanInstance *QCocoaIntegration::getCocoaVulkanInstance() const
+{
+    return mCocoaVulkanInstance;
+}
+#endif
+
 QCoreTextFontDatabase *QCocoaIntegration::fontDatabase() const
 {
     return mFontDb.data();