Also detect debug build, clarified instructions

Source/ThirdParty/VtkLibrary/VtkLibrary.Build.cs

@@ -1,6 +1,7 @@
 // Fill out your copyright notice in the Description page of Project Settings.
 
 using System;
+using System.Diagnostics;
 using System.IO;
 using UnrealBuildTool;
 
@@ -12,6 +13,12 @@ public VtkLibrary(ReadOnlyTargetRules Target) : base(Target)
 
 		// If you want to load a debug build, specify here the Debug directory
 		var BuildDir = "Release";
+
+		if (!Directory.Exists(Path.Combine(ModuleDirectory, "Release")) && Directory.Exists(Path.Combine(ModuleDirectory, "Debug")))
+		{
+			Console.WriteLine("[VtkPlugin] Searched for Release folder but only found Debug, so chose Debug.");
+			BuildDir = "Debug";
+		}
 
 		// Load includes
 		PublicSystemIncludePaths.Add("$(ModuleDir)/Public");
@@ -23,7 +30,7 @@ public VtkLibrary(ReadOnlyTargetRules Target) : base(Target)
 			var dllSearchPath = Path.Combine(ModuleDirectory, BuildDir, "bin");
 
 			if (!Directory.Exists(libSearchPath) || !Directory.Exists(dllSearchPath))
-				Console.WriteLine("Did not find lib- or dll-path for VtkLibrary!");
+				Console.WriteLine("[VtkPlugin] Did not find lib- or dll-path for VtkLibrary!");
 
 			// Libs
 			foreach (var libPath in Directory.EnumerateFiles(libSearchPath, "*.lib"  , SearchOption.AllDirectories))
@@ -47,7 +54,24 @@ public VtkLibrary(ReadOnlyTargetRules Target) : base(Target)
 
 				// This adds a runtime dependency & copies the dll from source path to destination path on build
 				RuntimeDependencies.Add(destPath, srcPath);
+			}
+
+			// DLLs
+			foreach (var filePath in Directory.EnumerateFiles(dllSearchPath, "*.pdb"  , SearchOption.AllDirectories))
+			{
+				var dllName = Path.GetFileName(filePath);
+				var srcPath = Path.Combine("$(ModuleDir)", BuildDir, "bin", dllName);
+				var destPath = Path.Combine("$(BinaryOutputDir)", dllName);
+
+				// TODO: Investigate why we can't delayload VTK like this on Windows, uncomment if fix is found
+				// This prevents the dlls to be auto-loaded when the plugin is read
+				// and allows us to load them later in VtkPlugin.cpp during StartupModule.
+				// That allows us to load dlls from specific paths, which is not (easily) possible otherwise on Windows.
+				//PublicDelayLoadDLLs.Add(dllName);
+				//RuntimeDependencies.Add(srcPath);
 
+				// This adds a runtime dependency & copies the dll from source path to destination path on build
+				RuntimeDependencies.Add(destPath, srcPath);
 			}
 		}
 		else if (Target.Platform == UnrealTargetPlatform.Mac)

readme.md

@@ -1,7 +1,5 @@
 ## VTK Plugin for Unreal Engine 5+
 
-**This branch is fully cross-compatible between Windows and Unix (Linux/Mac).** See "How" in the [Remarks on Linux/Mac](#remarks-on-linuxmac) section.
-
 A plugin that links the [VTK Library](https://github.com/Kitware/VTK) to [Unreal Engine 5.3](https://docs.unrealengine.com/5.3/en-US/).
 
 Currently, this plugin does the following:
@@ -14,21 +12,17 @@ Currently, this plugin does the following:
 This plugin is quite verbose as it aims to be a foundation for implementing & testing VTK functionality in UE.
 Check the Unreal Log for `[VtkPlugin]` to see what's happening (also valid for the blueprint functions).
 
-### ✔️ Remarks on Windows
-
-Delay-loading (which would be better practice) is currently disabled for Windows and all VTK dlls are instantly loaded.
-This prevents module reloading.
+### ⚠️ Remarks on Windows
 
-### ✔️ Remarks on Linux/Mac
+- Delay-loading (which would be better practice) is currently disabled and all VTK dlls are instantly loaded.
+  - This prevents module reloading.
 
-Delay-loading is enabled on Unix-based systems and thus also module reloading (theoretically).
+### ⚠️ Remarks on Linux/Mac
 
-To achieve cross-compatibility of all VTK methods, the `VtkWrapper` module with [RTTI](https://en.wikipedia.org/wiki/Run-time_type_information) enabled was implemented to wrap all VTK-native code.
-Each VTK functionality needs to be wrapped explicitly before it is exposed (e.g., to `VtkPlugin` which implements the blueprints).  
-This is needed, as contrary to Windows Unreal Engine on Unix is by default compiled without RTTI support (thoroughly discussed [here](https://forums.unrealengine.com/t/rtti-failed-compiling-when-enabled-for-4-23-linux/455083/22)).
-Globally enabling RTTI on Unix is not (easily) done, so this approach orients the way the `OpenExrWrapper` is implemented as suggested [here](https://forums.unrealengine.com/t/rtti-failed-compiling-when-enabled-for-4-23-linux/455083/13).
-
-⚠️ The provided `VtkWrapper` implementation is just an example and better solutions exist.
+- Cross-compatibility only through an [RTTI](https://en.wikipedia.org/wiki/Run-time_type_information) enabled Wrapper module (`VtkWrapper`)
+  - Using PImpl pattern
+  - UE on Unix is per default compiled without RTTI and will clash with RTTI-functionality used in some VTK includes ([also discussed here](https://forums.unrealengine.com/t/rtti-failed-compiling-when-enabled-for-4-23-linux/455083/22))
+  - Wrapper modules also employed by Unreal, e.g., in the `OpenExrWrapper` ([see here](https://forums.unrealengine.com/t/rtti-failed-compiling-when-enabled-for-4-23-linux/455083/13))
 
 ## Installation
 
@@ -37,13 +31,13 @@ Globally enabling RTTI on Unix is not (easily) done, so this approach orients th
 You can use the `[*.bat|*.sh|*.command]` installation scripts to download and build VTK for UE automatically.
 
 By default it will do a `Release` build, but you can tell it to do a `Debug` build by starting it with `Debug` as a parameter.  
-**If you do a Debug build,** be aware to change the respective paths in your `VtkLibrary.Build.cs` and `VtkPlugin.cpp` to `Debug` as well.
+**If you do a Debug build,** don't delete your build folder (`./Temporary`) at the end of the script. The `*.dll` files store the path to its debug symbols which remain there.
 
 ```powershell 
 # Release build
 .\install_vtk_windows.bat
 
-# Debug build
+# Debug build (do not delete build folder at the end)
 .\install_vtk_windows.bat debug
 ```
 
@@ -67,9 +61,6 @@ Alternatively, download & build the VTK library yourself and copy the files to t
 
 For test data have a look at the VTKData repository (files here are referenced in the [official VTK examples](https://examples.vtk.org/site/Cxx)): https://github.com/open-cv/VTKData
 
-If you are using Linux or Mac the scripts or configuration may not be fully functional.
-Please consider a pull request if this is the case and you fix it. :-)
-
 If there are linking errors with the VTK library, have a look in the `Source/ThirdParty/VtkLibrary` folder:
 - Check if your VTK binaries are in the correct folder
 - Check if your VTK includes are present