Dear ImGui in Unreal Engine 5 with C++

Using the Dear ImGui free and open-source graphical user interface library within Unreal Engine. This tutorial is specific to Unreal Engine 5.0.1 with ImGui 1.8.7 using the plugin fork linked below.
Tutorial Project on Github: github.com/stungeye/UE5-With-...
ImGui: github.com/ocornut/imgui
UnrealImGui Plugin Fork: github.com/benui-dev/UnrealImGui
More complex example code: github.com/segross/UnrealImGu...
00:00:00 Video Intro
00:00:44 ImGui Library & Plugin
00:02:19 UE5 C++ Project
00:03:41 Installing & Building Plugin
00:06:04 Testing the Plugin
00:07:34 Configuring C++ Project
00:14:20 ImGui Input Toggle
00:16:00 Custom ImGui Window
00:19:59 Hook Actor to imGui Slider
00:24:16 Display FPS in ImGui

[@stungeye]

I made a short (4 minute) follow-up to this video with a fix that allows for multiple actors, each with their own ImGui window: kzbin.info/www/bejne/pYSUp39-dpiSoNk

[@robertmajewski4479]

Hello, thank you for the tutorial. About solution and projects files: those are only for visual studio to show the project structure. They are not used by unreal to build. Those project files need to be regenerated every time when a new file is added to the ue5 project or uproject/uplugin is changed. You don't have to close VS. Just run the script to regenerate VS files and VS will detect that and reload.

[@stungeye]

Thanks. This is great additional information on the build process and VS.

[@_svk_4339]

Hi Great tutorial, hoping to see many more. Can you share how would I be able to rotate an actor (cube) in x, y, z using imgui sliders?

[@stungeye]

The process would be very similar, however you'd need to floats to store the changes to the pitch, yaw, and roll. Rotation based on these could then be handled as shown here: unrealcpp.com/rotating-actor/

[@FQQQF]

I like it, but this option will scale any 3d object, how do you attach it to a specific 3d object ?

[@stungeye]

Currently the ImGui code I've added is attached a specific objects (instances of BP_ImGuiActor). That said, my use of a static variables (for Scale and ScaleOld) and a non-unique ImGui window name, means that multiple BP_ImGuiActor's in a scene won't work properly. I've updated the code in the associated github repo (github.com/stungeye/UE5-With-Dear-ImGui) to add support for multiple actors, each one being scaled by a different ImGui window. The one issue is that all these ImGui windows may spawn at the same position on the canvas and will have to be dragged around to separate positions.

[@stungeye]

I've created a short follow-up video with a fix that allows for individual control of each actor's scale: kzbin.info/www/bejne/pYSUp39-dpiSoNk

[@OCanalDeVideoGames]

my keyboard shortcut is not working, bro, cant toggle by the shortcut

[@andycunningham3634]

Wondering have you tried getting multiple imgui contexts to work. Basically to have imgui in another slate window instead of just the main gameviewport.

[@stungeye]

Haven't tried that yet. Have you had any success with multiple imgui contexts with Unreal?

[@TheSilverlost]

Is there any way to use the Docking version ?

[@stungeye]

I haven't experimented with the docking branch in the context of Unreal. Please let me know if you find a way.

[@TheSilverlost]

@@stungeye So I've made docking work, haven't test everything the docking branch has to offer tho but the docking feature work I downloaded the docking branch on Github, replaced files in "/Plugins/ImGui/Source/ThirdParty/ImGuiLibrary" with the one from the docking branch. Then went into the FImGuiContextProxy class constructor, and added those line. IO.ConfigFlags |= ImGuiConfigFlags_DockingEnable; IO.ConfigFlags |= ImGuiConfigFlags_ViewportsEnable; // MultiViewport dont work right now Didnt bother making multi-viewport work as it is not valuable to me. In case your asking the version is V1.89 WIP.

[@stungeye]

@@TheSilverlost Wow. AWESOME! Glad to hear it wasn't a battle to get it working.

[@johannharding8161]

Has anyone managed to make it work with 5.2? I get failure after clicking yes to rebuild. =(

[@stungeye]

There's a pull request on the repo with a compilation fix for 5.1: github.com/benui-dev/UnrealImGui/pull/1 The two commits on this request are super short, so you could likely just paste 'em into your copy of UnrealImGui.

[@johannharding8161]

​@@stungeye After copying the fix into the files, I still had to open the solution and fix a "bug" in SImGuiCanvasControl.cpp line 179. I changed it to: "const FVector2D DragDelta = static_cast(ScreenToWidget.TransformVector(DragDropEvent.GetScreenSpacePosition() - Operation->StartPosition)); Added " #include "Math/Vector2D.h" " also. now it works for me and I get to see the demo. I am not a pro at this so it might not be the best solution. Thanks for your reply =)

[@stungeye]

@@johannharding8161 Nice one. Glad you were able to get it working. You might want to flag the additional bug you had to fix as an issue on the repo.

[@lintan8071]

Why can't I load fonts？ In UE5