Creating Editor Visualization for Move Component in Unreal Engine 5 C++

Previous Video Recap

• Topics Covered: Move component, actors, and components
• Move Component: Moved an object around the scene with an FVector move offset (3D vector) and a speed parameter to control movement.
• Drawbacks: No visualization of where the object was moving, making it frustrating to set up correctly.

Today's Objective

• Goal: Add editor visualization for the move component using Unreal Engine's editor modules and interfaces.
• Steps: Understanding Unreal Engine core concepts and modules, followed by creating and registering the editor module.

Core Concepts of Unreal Engine

• Modules: Containers with headers and source code serving specific purposes (engine, editor, game, plugins).
• Example (Visual Studio structure):
  • Runtime directory (contains modules like D3D12RHI for DirectX 12).
  • Source directory (contains the project-specific modules like newCPPTutorial).

Creating an Editor Module

Step 1: Modify Project File

• Project File: Add a new module entry in the .uproject file.

  {
      "Name": "newCPPTutorialEditor",
      "Type": "Editor",
      "LoadingPhase": "PostEngineInit"
  }
  

• Reason: Separate game code from editor-specific code for clear distinction and shipping purposes.

Step 2: Modify Target File

• Target File: Add the new module in newCPPTutorialEditor.Target.cs.

  ExtraModuleNames.AddRange(new string[] { "newCPPTutorial", "newCPPTutorialEditor" });
  

• Create Module Folder: In Source directory, add newCPPTutorialEditor folder and create necessary files (.Build.cs, source files).

Step 3: Implementing Editor Module

Editor Module Header (.h file)

• Create File: newCPPTutorialEditor.h

  class FNewCPPTutorialEditorModule : public IModuleInterface
  {
      public:
          virtual void StartupModule() override;
          virtual void ShutdownModule() override;
  };
  

Editor Module Source (.cpp file)

• Create File: newCPPTutorialEditor.cpp

  #include "newCPPTutorialEditor.h"
  IMPLEMENT_MODULE(FNewCPPTutorialEditorModule, newCPPTutorialEditor)
  

• Build File: Add dependencies.

  PublicDependencyModuleNames.AddRange(new string[] { "newCPPTutorial", "UnrealEd" });
  

Step 4: Register Component Visualizer

• Create Visualizer Files: newCPPTutorialEditor/MoveComponentVisualizer.h and .cpp

  class FMoveComponentVisualizer : public FComponentVisualizer {
      // Define methods here
  }
  

• Register Visualizer in StartupModule

  void FNewCPPTutorialEditorModule::StartupModule() {
      if (GUnrealEd) {
          TSharedPtr<FMoveComponentVisualizer> Visualizer = MakeShareable(new FMoveComponentVisualizer);
          GUnrealEd->RegisterComponentVisualizer(UMoveComponent::StaticClass()->GetFName(), Visualizer);
          Visualizer->OnRegister();
      }
  }
  

• Unregister in ShutdownModule

  void FNewCPPTutorialEditorModule::ShutdownModule() {
      if (GUnrealEd) {
          GUnrealEd->UnregisterComponentVisualizer(UMoveComponent::StaticClass()->GetFName());
      }
  }
  

Implementing Draw Visualization Function

• Header File: MoveComponentVisualizer.h

  virtual void DrawVisualization(const UActorComponent* Component, const FSceneView* View, FPrimitiveDrawInterface* PDI) override;
  

• Source File: MoveComponentVisualizer.cpp

  void FMoveComponentVisualizer::DrawVisualization(const UActorComponent* Component, const FSceneView*, FPrimitiveDrawInterface* PDI) {
      // Implement draw logic
  }
  

• Draw Line Example:

  PDI->DrawLine(StartVector, EndVector, FLinearColor::Red, SDPG_World);
  

Final Steps

• Build and Test: Ensure Unreal Engine compiles successfully and the editor visualizations appear as intended.
• Debugging: Use the Module panel in Unreal Engine to check if modules load correctly.

Conclusion

• Outcome: Successfully added in-editor visualization for Move Component.
• Next Steps: Improve move functionality, allowing interactions with Blueprints, dynamic pausing, and resetting movements.

Stay tuned for more tutorials!