Implement vkGetRefreshCycleDurationGOOGLE() for macOS.
So far it always returned a 60 Hz refresh on macOS. Now we query the
actual refresh interval for the NSScreen on which our swapChain is likely
displaying.
Tested on a MacBookPro dual-display setup with builtin 60 Hz Retina panel
and external 100 Hz monitor, showing proper reporting depending on which
monitor the window was displaying on. Tested on macOS 10.15.7 only.
diff --git a/MoltenVK/MoltenVK/GPUObjects/MVKSwapchain.mm b/MoltenVK/MoltenVK/GPUObjects/MVKSwapchain.mm
index 7eb2702..6929853 100644
--- a/MoltenVK/MoltenVK/GPUObjects/MVKSwapchain.mm
+++ b/MoltenVK/MoltenVK/GPUObjects/MVKSwapchain.mm
@@ -29,10 +29,17 @@
#import "CAMetalLayer+MoltenVK.h"
#import "MVKBlockObserver.h"
-#if MVK_IOS_OR_TVOS
+#if MVK_IOS_OR_TVOS || MVK_MACCAT
# include <UIKit/UIScreen.h>
#endif
+#if MVK_MACOS && !MVK_MACCAT
+# include <AppKit/NSApplication.h>
+# include <AppKit/NSScreen.h>
+# include <AppKit/NSWindow.h>
+# include <AppKit/NSView.h>
+#endif
+
#include <libkern/OSByteOrder.h>
using namespace std;
@@ -408,15 +415,33 @@
VkResult MVKSwapchain::getRefreshCycleDuration(VkRefreshCycleDurationGOOGLE *pRefreshCycleDuration) {
if (_device->getConfigurationResult() != VK_SUCCESS) { return _device->getConfigurationResult(); }
+#if MVK_IOS_OR_TVOS || MVK_MACCAT
NSInteger framesPerSecond = 60;
-#if MVK_IOS_OR_TVOS
UIScreen* screen = [UIScreen mainScreen];
if ([screen respondsToSelector: @selector(maximumFramesPerSecond)]) {
framesPerSecond = screen.maximumFramesPerSecond;
}
#endif
-#if MVK_MACOS
- // TODO: hook this up for macOS, probably need to use CGDisplayModeGetRefeshRate
+
+#if MVK_MACOS && !MVK_MACCAT
+ // Find the screen for the window whose content view is backed by the swapchains CAMetalLayer.
+ // Default to the mainScreen if no such window can be found.
+ NSScreen *screen = [NSScreen mainScreen];
+ for (NSWindow* window in [[NSApplication sharedApplication] windows]) {
+ NSView *view = [window contentView];
+ if (view && ([view layer] == _mtlLayer)) {
+ screen = [window screen];
+ }
+ }
+
+ CGDirectDisplayID displayId = [[[screen deviceDescription] objectForKey:@"NSScreenNumber"] unsignedIntValue];
+ CGDisplayModeRef mode = CGDisplayCopyDisplayMode(displayId);
+ double framesPerSecond = CGDisplayModeGetRefreshRate(mode);
+ CGDisplayModeRelease(mode);
+
+ // Builtin panels, e.g., on MacBook, report a zero refresh rate.
+ if (framesPerSecond == 0)
+ framesPerSecond = 60.0;
#endif
pRefreshCycleDuration->refreshDuration = (uint64_t)1e9 / framesPerSecond;
