From b4e959ccd3f46d7d924f0800525cd28517858702 Mon Sep 17 00:00:00 2001
From: Sebastian <sebastian.e.gross@gmail.com>
Date: Wed, 17 Oct 2018 23:16:28 +0100
Subject: [PATCH] Changed module type to allow stripping it from selected
 builds: - Changed module type to 'Developer'. - Added runtime loader that
 handles automatic module loading in runtime builds (feature can be
 selectively enabled).

---
 ImGui.uplugin                        |  2 +-
 Source/ImGui/ImGui.Build.cs          | 12 +++++++
 Source/ImGui/Private/ImGuiModule.cpp | 52 ++++++++++++++++++++++++++++
 3 files changed, 65 insertions(+), 1 deletion(-)

diff --git a/ImGui.uplugin b/ImGui.uplugin
index 5c515ae..586d533 100644
--- a/ImGui.uplugin
+++ b/ImGui.uplugin
@@ -16,7 +16,7 @@
 	"Modules": [
 		{
 			"Name": "ImGui",
-			"Type": "RuntimeNoCommandlet",
+			"Type": "Developer",
 			"LoadingPhase": "PreDefault"
 		}
 	]
diff --git a/Source/ImGui/ImGui.Build.cs b/Source/ImGui/ImGui.Build.cs
index bc92c60..2ac7ce8 100644
--- a/Source/ImGui/ImGui.Build.cs
+++ b/Source/ImGui/ImGui.Build.cs
@@ -1,5 +1,6 @@
 // Distributed under the MIT License (MIT) (see accompanying LICENSE file)
 
+using System.Collections.Generic;
 using System.IO;
 using UnrealBuildTool;
 
@@ -18,6 +19,11 @@ public class ImGui : ModuleRules
 		bool bBuildEditor = (Target.Type == TargetRules.TargetType.Editor);
 #endif
 
+		// Developer modules are automatically loaded only in editor builds but can be stripped out from other builds.
+		// Enable runtime loader, if you want this module to be automatically loaded in runtime builds (monolithic).
+		bool bEnableRuntimeLoader = true;
+
+
 		PublicIncludePaths.AddRange(
 			new string[] {
 				Path.Combine(ModuleDirectory, "../ThirdParty/ImGuiLibrary/Include"),
@@ -78,5 +84,11 @@ public class ImGui : ModuleRules
 				// ... add any modules that your module loads dynamically here ...
 			}
 			);
+
+
+#if !UE_4_19_OR_LATER
+		List<string> PrivateDefinitions = Definitions;
+#endif
+		PrivateDefinitions.Add(string.Format("RUNTIME_LOADER_ENABLED = {0}", bEnableRuntimeLoader ? 1 : 0));
 	}
 }
diff --git a/Source/ImGui/Private/ImGuiModule.cpp b/Source/ImGui/Private/ImGuiModule.cpp
index 90efc75..b77b6f2 100644
--- a/Source/ImGui/Private/ImGuiModule.cpp
+++ b/Source/ImGui/Private/ImGuiModule.cpp
@@ -221,6 +221,58 @@ void FImGuiModule::ToggleShowDemo()
 	SetShowDemo(!IsShowingDemo());
 }
 
+
+//----------------------------------------------------------------------------------------------------
+// Runtime loader
+//----------------------------------------------------------------------------------------------------
+
+#if !WITH_EDITOR && RUNTIME_LOADER_ENABLED
+
+class FImGuiModuleLoader
+{
+	FImGuiModuleLoader()
+	{
+		if (!Load())
+		{
+			FModuleManager::Get().OnModulesChanged().AddRaw(this, &FImGuiModuleLoader::LoadAndRelease);
+		}
+	}
+
+	// For different engine versions.
+	static FORCEINLINE bool IsValid(const TSharedPtr<IModuleInterface>& Ptr) { return Ptr.IsValid(); }
+	static FORCEINLINE bool IsValid(const IModuleInterface* const Ptr) { return Ptr != nullptr; }
+
+	bool Load()
+	{
+		return IsValid(FModuleManager::Get().LoadModule(ModuleName));
+	}
+
+	void LoadAndRelease(FName Name, EModuleChangeReason Reason)
+	{
+		// Avoid handling own load event.
+		if (Name != ModuleName)
+		{
+			// Try loading until success and then release.
+			if (Load())
+			{
+				FModuleManager::Get().OnModulesChanged().RemoveAll(this);
+			}
+		}
+	}
+
+	static FName ModuleName;
+
+	static FImGuiModuleLoader Instance;
+};
+
+FName FImGuiModuleLoader::ModuleName = "ImGui";
+
+// In monolithic builds this will start loading process.
+FImGuiModuleLoader FImGuiModuleLoader::Instance;
+
+#endif // !WITH_EDITOR && RUNTIME_LOADER_ENABLED
+
+
 //----------------------------------------------------------------------------------------------------
 // Partial implementations of other classes that needs access to ImGuiModuleManager
 //----------------------------------------------------------------------------------------------------