Merge branch 'dev/FixBackbufferSwapchain' of https://github.com/ifromstone/FlaxEngine into ifromstone-dev/FixBackbufferSwapchain

# Conflicts:
#	Source/Engine/GraphicsDevice/Vulkan/GPUSwapChainVulkan.cpp

Source/Engine/GraphicsDevice/Vulkan/GPUSwapChainVulkan.cpp

@@ -25,16 +25,23 @@ void BackBufferVulkan::Setup(GPUSwapChainVulkan* window, VkImage backbuffer, Pix
     ImageAcquiredSemaphore = New<SemaphoreVulkan>(Device);
 }
 
+void BackBufferVulkan::WaitForSubmit()
+{
+    if (SubmitCmdBuffer)
+    {
+        if (SubmitCmdBufferFenceCounter == SubmitCmdBuffer->GetFenceSignaledCounter())
+            SubmitCmdBuffer->Wait();
+        SubmitCmdBuffer = nullptr;
+        SubmitCmdBufferFenceCounter = 0;
+    }
+}
+
 void BackBufferVulkan::Release()
 {
+    WaitForSubmit();
     Handle.Release();
     Delete(RenderingDoneSemaphore);
     Delete(ImageAcquiredSemaphore);
-    if (SubmitCmdBuffer)
-    {
-        SubmitCmdBuffer->Wait();
-        SubmitCmdBuffer = nullptr;
-    }
     Device = nullptr;
 }
 
@@ -138,6 +145,14 @@ GPUTextureView* GPUSwapChainVulkan::GetBackBufferView()
         }
         ASSERT(_acquiredImageIndex != -1);
 
+        auto context = _device->MainContext;
+
+        // Wait for prior GPU work that used this acquired image before recording
+        // commands against it again. Waiting before acquire can target a different image
+        // and unnecessarily serialize frames when the swapchain has multiple images.
+        auto& acquiredBackBuffer = _backBuffers[_acquiredImageIndex];
+        acquiredBackBuffer.WaitForSubmit();
+
         const auto backBuffer = &_backBuffers[_acquiredImageIndex].Handle;
 
         auto cmdBuffer = cmdBufferManager->GetCmdBuffer();
@@ -158,17 +173,6 @@ GPUTextureView* GPUSwapChainVulkan::GetBackBufferView()
 void GPUSwapChainVulkan::Begin(RenderTask* task)
 {
     GPUSwapChain::Begin(task);
-
-    // Wait for the backbuffer to be available
-    if (_currentImageIndex != -1)
-    {
-        auto& backBuffer = _backBuffers[_currentImageIndex];
-        if (backBuffer.SubmitCmdBuffer)
-        {
-            backBuffer.SubmitCmdBuffer->Wait();
-            backBuffer.SubmitCmdBuffer = nullptr;
-        }
-    }
 }
 
 bool GPUSwapChainVulkan::Resize(int32 width, int32 height)
@@ -616,6 +620,7 @@ void GPUSwapChainVulkan::Present(bool vsync)
     acquiredBackBuffer.SubmitCmdBuffer = context->GetCmdBufferManager()->GetActiveCmdBuffer();
 
     context->GetCmdBufferManager()->SubmitActiveCmdBuffer(_backBuffers[_acquiredImageIndex].RenderingDoneSemaphore);
+    acquiredBackBuffer.SubmitCmdBufferFenceCounter = acquiredBackBuffer.SubmitCmdBuffer->GetSubmittedFenceCounter();
 
     // Present the back buffer to the viewport window
     const auto result = TryPresent(DoPresent, _device->PresentQueue, true);

Source/Engine/GraphicsDevice/Vulkan/GPUSwapChainVulkan.h

@@ -34,6 +34,11 @@ public:
     /// </summary>
     CmdBufferVulkan* SubmitCmdBuffer = nullptr;
 
+    /// <summary>
+    /// The fence counter value for SubmitCmdBuffer at the time it was submitted.
+    /// </summary>
+    uint64 SubmitCmdBufferFenceCounter = 0;
+
     /// <summary>
     /// The render target surface handle.
     /// </summary>
@@ -41,6 +46,7 @@ public:
 
 public:
     void Setup(GPUSwapChainVulkan* window, VkImage backbuffer, PixelFormat format, VkExtent3D extent);
+    void WaitForSubmit();
     void Release();
 
 public:

Source/Engine/Platform/iOS/iOSPlatform.cpp

@@ -350,7 +350,13 @@ MessagePipeline MainThreadPipeline;
 
     // Create UI thread update callback
     self.displayLink = [CADisplayLink displayLinkWithTarget:self selector:@selector(UIThreadMain)];
-    self.displayLink.preferredFramesPerSecond = 60;
+    const int32 targetFrameRate = 60;
+#if __IPHONE_OS_VERSION_MAX_ALLOWED >= 150000
+    if (@available(iOS 15.0, *))
+        self.displayLink.preferredFrameRateRange = CAFrameRateRangeMake(targetFrameRate, targetFrameRate, targetFrameRate);
+    else
+#endif
+        self.displayLink.preferredFramesPerSecond = targetFrameRate;
     [self.displayLink addToRunLoop:[NSRunLoop currentRunLoop] forMode:NSRunLoopCommonModes];
 
     // Run engine on a separate main thread

Source/Platforms/iOS/Binaries/Project/FlaxGame.xcodeproj/project.pbxproj

@@ -295,6 +295,7 @@ ${PBXResourcesGroup}
 				GENERATE_INFOPLIST_FILE = YES;
 				INFOPLIST_FILE = FlaxGame/Info.plist;
 				INFOPLIST_KEY_CFBundleDisplayName = "${ProjectName}";
+				INFOPLIST_KEY_CADisableMinimumFrameDurationOnPhone = YES;
 				INFOPLIST_KEY_LSApplicationCategoryType = "public.app-category.games";
 				INFOPLIST_KEY_UIApplicationSupportsIndirectInputEvents = YES;
 				INFOPLIST_KEY_UILaunchStoryboardName = LaunchScreen;
@@ -336,6 +337,7 @@ ${PBXResourcesGroup}
 				GENERATE_INFOPLIST_FILE = YES;
 				INFOPLIST_FILE = FlaxGame/Info.plist;
 				INFOPLIST_KEY_CFBundleDisplayName = "${ProjectName}";
+				INFOPLIST_KEY_CADisableMinimumFrameDurationOnPhone = YES;
 				INFOPLIST_KEY_LSApplicationCategoryType = "public.app-category.games";
 				INFOPLIST_KEY_UIApplicationSupportsIndirectInputEvents = YES;
 				INFOPLIST_KEY_UILaunchStoryboardName = LaunchScreen;

Source/Platforms/iOS/Binaries/Project/FlaxGame/Info.plist

@@ -2,6 +2,8 @@
 <!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
 <plist version="1.0">
 <dict>
+	<key>CADisableMinimumFrameDurationOnPhone</key>
+	<true/>
 	<key>UIApplicationSceneManifest</key>
 	<dict>
 		<key>UIApplicationSupportsMultipleScenes</key>