Support for refresh rate and sync interval (#2989)

* Add support for querying the refresh rate and sync interval

Code/Framework/AzFramework/AzFramework/Windowing/NativeWindow.cpp

@@ -10,6 +10,17 @@
 
 #include <AzCore/Console/IConsole.h>
 
+void OnVsyncIntervalChanged(uint32_t const& interval)
+{
+    AzFramework::WindowNotificationBus::Broadcast(
+        &AzFramework::WindowNotificationBus::Events::OnVsyncIntervalChanged, AZ::GetClamp(interval, 0u, 4u));
+}
+
+// NOTE: On change, broadcasts the new requested vsync interval to all windows.
+// The value of the vsync interval is constrained between 0 and 4
+// Vsync intervals greater than 1 are not currently supported on the Vulkan RHI (see #2061 for discussion)
+AZ_CVAR(uint32_t, vsync_interval, 1, OnVsyncIntervalChanged, AZ::ConsoleFunctorFlags::Null, "Set swapchain vsync interval");
+
 namespace AzFramework
 {
     //////////////////////////////////////////////////////////////////////////
@@ -122,6 +133,16 @@ namespace AzFramework
         return m_pimpl->GetDpiScaleFactor();
     }
 
+    uint32_t NativeWindow::GetDisplayRefreshRate() const
+    {
+        return m_pimpl->GetDisplayRefreshRate();
+    }
+
+    uint32_t NativeWindow::GetSyncInterval() const
+    {
+        return vsync_interval;
+    }
+
     /*static*/ bool NativeWindow::GetFullScreenStateOfDefaultWindow()
     {
         NativeWindowHandle defaultWindowHandle = nullptr;
@@ -240,4 +261,10 @@ namespace AzFramework
         return 1.0f;
     }
 
+    uint32_t NativeWindow::Implementation::GetDisplayRefreshRate() const
+    {
+        // Default to 60
+        return 60;
+    }
+
 } // namespace AzFramework

Code/Framework/AzFramework/AzFramework/Windowing/NativeWindow.h

@@ -130,6 +130,8 @@ namespace AzFramework
         bool CanToggleFullScreenState() const override;
         void ToggleFullScreenState() override;
         float GetDpiScaleFactor() const override;
+        uint32_t GetSyncInterval() const override;
+        uint32_t GetDisplayRefreshRate() const override;
 
         //! Get the full screen state of the default window.
         //! \return True if the default window is currently in full screen, false otherwise.
@@ -172,6 +174,7 @@ namespace AzFramework
             virtual void SetFullScreenState(bool fullScreenState);
             virtual bool CanToggleFullScreenState() const;
             virtual float GetDpiScaleFactor() const;
+            virtual uint32_t GetDisplayRefreshRate() const;
 
         protected:
             uint32_t m_width = 0;

Code/Framework/AzFramework/AzFramework/Windowing/WindowBus.h

@@ -74,6 +74,12 @@ namespace AzFramework
         //! to a "standard" value of 96, the default for Windows in a DPI unaware setting. This can
         //! be used to scale user interface elements to ensure legibility on high density displays.
         virtual float GetDpiScaleFactor() const = 0;
+
+        //! Returns the sync interval which tells the drivers the number of v-blanks to synchronize with
+        virtual uint32_t GetSyncInterval() const = 0;
+
+        //! Returns the refresh rate of the main display
+        virtual uint32_t GetDisplayRefreshRate() const = 0;
     };
     using WindowRequestBus = AZ::EBus<WindowRequests>;
 
@@ -101,6 +107,9 @@ namespace AzFramework
 
         //! This is called when vsync interval is changed.
         virtual void OnVsyncIntervalChanged(uint32_t interval) { AZ_UNUSED(interval); };
+
+        //! This is called if the main display's refresh rate changes
+        virtual void OnRefreshRateChanged([[maybe_unused]] uint32_t refreshRate) {}
     };
     using WindowNotificationBus = AZ::EBus<WindowNotifications>;