Fixes to get compiling with Unreal 5.0 Preview 1

ImGui.uplugin

@@ -16,8 +16,14 @@
 	"Modules": [
 		{
 			"Name": "ImGui",
-			"Type": "Developer",
+			"Type": "DeveloperTool",
 			"LoadingPhase": "PreDefault"
 		}
+	],
+	"Plugins": [
+		{
+			"Name": "EnhancedInput",
+			"Enabled": true
+		}
 	]
 }

Source/ImGui/ImGui.Build.cs

@@ -33,7 +33,7 @@ public ImGui(TargetInfo Target)
 
 		PublicIncludePaths.AddRange(
 			new string[] {
-				Path.Combine(ModuleDirectory, "../ThirdParty/ImGuiLibrary/Include")
+				Path.Combine(ModuleDirectory, "../ThirdParty/ImGuiLibrary/Include"),
 				// ... add public include paths required here ...
 			}
 			);
@@ -42,7 +42,7 @@ public ImGui(TargetInfo Target)
 		PrivateIncludePaths.AddRange(
 			new string[] {
 				"ImGui/Private",
-				"ThirdParty/ImGuiLibrary/Private"
+				"ThirdParty/ImGuiLibrary/Private",
 				// ... add other private include paths required here ...
 			}
 			);
@@ -62,6 +62,7 @@ public ImGui(TargetInfo Target)
 			new string[]
 			{
 				"CoreUObject",
+				"EnhancedInput",
 				"Engine",
 				"InputCore",
 				"Slate",

Source/ImGui/Private/ImGuiContextManager.cpp

@@ -5,6 +5,7 @@
 #include "ImGuiDelegatesContainer.h"
 #include "ImGuiImplementation.h"
 #include "ImGuiModuleSettings.h"
+#include "ImGuiModule.h"
 #include "Utilities/WorldContext.h"
 #include "Utilities/WorldContextIndex.h"
 
@@ -254,14 +255,29 @@ void FImGuiContextManager::SetDPIScale(const FImGuiDPIScaleInfo& ScaleInfo)
 	}
 }
 
-void FImGuiContextManager::BuildFontAtlas()
+void FImGuiContextManager::BuildFontAtlas(const TMap<FName, TSharedPtr<ImFontConfig>>& CustomFontConfigs)
 {
 	if (!FontAtlas.IsBuilt())
 	{
 		ImFontConfig FontConfig = {};
 		FontConfig.SizePixels = FMath::RoundFromZero(13.f * DPIScale);
 		FontAtlas.AddFontDefault(&FontConfig);
 
+		// Build custom fonts
+		for (const TPair<FName, TSharedPtr<ImFontConfig>>& CustomFontPair : CustomFontConfigs)
+		{
+			FName CustomFontName = CustomFontPair.Key;
+			TSharedPtr<ImFontConfig> CustomFontConfig = CustomFontPair.Value;
+
+			// Set font name for debugging
+			if (CustomFontConfig.IsValid())
+			{
+				strcpy_s(CustomFontConfig->Name, 40, TCHAR_TO_ANSI(*CustomFontName.ToString()));
+			}
+
+			FontAtlas.AddFont(CustomFontConfig.Get());
+		}
+
 		unsigned char* Pixels;
 		int Width, Height, Bpp;
 		FontAtlas.GetTexDataAsRGBA32(&Pixels, &Width, &Height, &Bpp);
@@ -283,5 +299,5 @@ void FImGuiContextManager::RebuildFontAtlas()
 		FontResourcesReleaseCountdown = 3;
 	}
 
-	BuildFontAtlas();
+	BuildFontAtlas(FImGuiModule::Get().GetProperties().GetCustomFonts());
 }

Source/ImGui/Private/ImGuiContextManager.h

@@ -66,6 +66,8 @@ class FImGuiContextManager
 
 	void Tick(float DeltaSeconds);
 
+	void RebuildFontAtlas();
+
 private:
 
 	struct FContextData
@@ -102,8 +104,7 @@ class FImGuiContextManager
 	FContextData& GetWorldContextData(const UWorld& World, int32* OutContextIndex = nullptr);
 
 	void SetDPIScale(const FImGuiDPIScaleInfo& ScaleInfo);
-	void BuildFontAtlas();
-	void RebuildFontAtlas();
+	void BuildFontAtlas(const TMap<FName, TSharedPtr<ImFontConfig>>& CustomFontConfigs = {});
 
 	TMap<int32, FContextData> Contexts;
 

Source/ImGui/Private/ImGuiContextProxy.cpp

@@ -92,7 +92,7 @@ FImGuiContextProxy::FImGuiContextProxy(const FString& InName, int32 InContextInd
 
 	// Start with the default canvas size.
 	ResetDisplaySize();
-	IO.DisplaySize = { DisplaySize.X, DisplaySize.Y };
+	IO.DisplaySize = {(float)DisplaySize.X, (float)DisplaySize.Y};
 
 	// Set the initial DPI scale.
 	SetDPIScale(InDPIScale);
@@ -211,7 +211,7 @@ void FImGuiContextProxy::BeginFrame(float DeltaTime)
 		ImGuiInterops::CopyInput(IO, InputState);
 		InputState.ClearUpdateState();
 
-		IO.DisplaySize = { DisplaySize.X, DisplaySize.Y };
+		IO.DisplaySize = { (float)DisplaySize.X, (float)DisplaySize.Y };
 
 		ImGui::NewFrame();
 

Source/ImGui/Private/ImGuiDrawData.cpp

@@ -29,7 +29,11 @@ void FImGuiDrawList::CopyVertexData(TArray<FSlateVertex>& OutVertexBuffer, const
 		SlateVertex.Position[1] = VertexPosition.Y;
 		SlateVertex.ClipRect = VertexClippingRect;
 #else
+#if ENGINE_COMPATIBILITY_LEGACY_VECTOR2F
 		SlateVertex.Position = Transform.TransformPoint(ImGuiInterops::ToVector2D(ImGuiVertex.pos));
+#else
+		SlateVertex.Position = (FVector2f)Transform.TransformPoint(ImGuiInterops::ToVector2D(ImGuiVertex.pos));
+#endif // ENGINE_COMPATIBILITY_LEGACY_VECTOR2F
 #endif // ENGINE_COMPATIBILITY_LEGACY_CLIPPING_API
 
 		// Unpack ImU32 color.
@@ -56,8 +60,4 @@ void FImGuiDrawList::TransferDrawData(ImDrawList& Src)
 	Src.CmdBuffer.swap(ImGuiCommandBuffer);
 	Src.IdxBuffer.swap(ImGuiIndexBuffer);
 	Src.VtxBuffer.swap(ImGuiVertexBuffer);
-
-	// ImGui seems to clear draw lists in every frame, but since source list can contain pointers to buffers that
-	// we just swapped, it is better to clear explicitly here.
-	Src.Clear();
 }

Source/ImGui/Private/ImGuiImplementation.cpp

@@ -6,7 +6,10 @@
 
 // For convenience and easy access to the ImGui source code, we build it as part of this module.
 // We don't need to define IMGUI_API manually because it is already done for this module.
-
+// UE 5.1 stopped defining PLATFORM_XBOXONE, so be safe if not defined
+#if !defined(PLATFORM_XBOXONE)
+	#define PLATFORM_XBOXONE 0
+#endif
 #if PLATFORM_XBOXONE
 // Disable Win32 functions used in ImGui and not supported on XBox.
 #define IMGUI_DISABLE_WIN32_DEFAULT_CLIPBOARD_FUNCTIONS
@@ -47,6 +50,8 @@ static FImGuiContextHandle ImGuiContextPtrHandle(ImGuiContextPtr);
 #include "imgui_draw.cpp"
 #include "imgui_widgets.cpp"
 
+#include "imgui_tables.cpp"
+
 #if PLATFORM_WINDOWS
 #include <Windows/HideWindowsPlatformTypes.h>
 #endif // PLATFORM_WINDOWS

Source/ImGui/Private/ImGuiInputHandler.cpp

@@ -79,12 +79,16 @@ FReply UImGuiInputHandler::OnKeyDown(const FKeyEvent& KeyEvent)
 		InputState->SetKeyDown(KeyEvent, true);
 		CopyModifierKeys(KeyEvent);
 
+		InputState->KeyDownEvents.Add(KeyEvent.GetKeyCode(), KeyEvent);
+
 		return ToReply(bConsume);
 	}
 }
 
 FReply UImGuiInputHandler::OnKeyUp(const FKeyEvent& KeyEvent)
 {
+	InputState->KeyUpEvents.Add(KeyEvent.GetKeyCode(), KeyEvent);
+
 	if (KeyEvent.GetKey().IsGamepadKey())
 	{
 		bool bConsume = false;
@@ -126,6 +130,15 @@ FReply UImGuiInputHandler::OnMouseButtonDown(const FPointerEvent& MouseEvent)
 	}
 
 	InputState->SetMouseDown(MouseEvent, true);
+	if (ModuleManager)
+	{
+		FImGuiContextProxy* Proxy = ModuleManager->GetContextManager().GetContextProxy(0);
+		if (Proxy)
+		{
+			//GEngine->AddOnScreenDebugMessage(15, 10, Proxy->WantsMouseCapture() ? FColor::Green : FColor::Red, TEXT("Handler Down"));
+			return ToReply(Proxy->WantsMouseCapture());
+		}
+	}
 	return ToReply(true);
 }
 

Source/ImGui/Private/ImGuiInputHandlerFactory.cpp

@@ -9,7 +9,7 @@
 #include <InputCoreTypes.h>
 
 
-UImGuiInputHandler* FImGuiInputHandlerFactory::NewHandler(const FStringClassReference& HandlerClassReference, FImGuiModuleManager* ModuleManager, UGameViewportClient* GameViewport, int32 ContextIndex)
+UImGuiInputHandler* FImGuiInputHandlerFactory::NewHandler(const FSoftClassPath& HandlerClassReference, FImGuiModuleManager* ModuleManager, UGameViewportClient* GameViewport, int32 ContextIndex)
 {
 	UClass* HandlerClass = nullptr;
 	if (HandlerClassReference.IsValid())

Source/ImGui/Private/ImGuiInputHandlerFactory.h

@@ -13,7 +13,7 @@ class FImGuiInputHandlerFactory
 {
 public:
 
-	static UImGuiInputHandler* NewHandler(const FStringClassReference& HandlerClassReference, FImGuiModuleManager* ModuleManager, UGameViewportClient* GameViewport, int32 ContextIndex);
+	static UImGuiInputHandler* NewHandler(const FSoftClassPath& HandlerClassReference, FImGuiModuleManager* ModuleManager, UGameViewportClient* GameViewport, int32 ContextIndex);
 
 	static void ReleaseHandler(UImGuiInputHandler* Handler);
 };

Source/ImGui/Private/ImGuiInputState.cpp

@@ -45,6 +45,9 @@ void FImGuiInputState::ClearUpdateState()
 {
 	ClearCharacters();
 
+	KeyDownEvents.Reset();
+	KeyUpEvents.Reset();
+
 	KeysUpdateRange.SetEmpty();
 	MouseButtonsUpdateRange.SetEmpty();
 

Source/ImGui/Private/ImGuiInputState.h

@@ -201,6 +201,9 @@ class FImGuiInputState
 	// and information about dirty parts of keys or mouse buttons arrays.
 	void ClearUpdateState();
 
+	TMap<uint32, FKeyEvent> KeyDownEvents;
+	TMap<uint32, FKeyEvent> KeyUpEvents;
+
 private:
 
 	void SetKeyDown(uint32 KeyIndex, bool bIsDown);