C++ in Unreal Engine: Extending Blueprints for Performance 🎯

Unreal Engine’s visual scripting system, Blueprints, is incredibly powerful and allows for rapid prototyping. However, when performance bottlenecks appear or you need to implement complex logic, C++ extending Blueprints Unreal Engine becomes essential. This post will guide you through the process of seamlessly integrating C++ code with your Blueprints, unlocking optimal performance and advanced features for your games. It’s a game-changer, trust us! 📈

Executive Summary

This article dives into how C++ can significantly boost the performance of your Unreal Engine projects by extending the capabilities of Blueprints. While Blueprints are excellent for quick iteration and visual scripting, C++ offers the raw power and control needed for computationally intensive tasks and complex systems. We’ll explore how to create C++ classes that are accessible within Blueprints, allowing designers and programmers to collaborate efficiently. Learn about creating custom Blueprint nodes, handling data efficiently, and optimizing performance-critical sections of your game. Unlock the full potential of Unreal Engine by bridging the gap between visual scripting and compiled code. This strategy improves both development speed and runtime performance, allowing you to ship smoother and more polished experiences.

Improving Game Logic with C++ Classes

Blueprints are fantastic for creating game logic, but sometimes you need the speed and control that C++ provides. Creating C++ classes that Blueprints can interact with is a crucial skill. This allows you to move performance-critical logic to C++, while still allowing designers to easily tweak parameters and behaviors in Blueprints.

• Creating a C++ Class: Start by creating a new C++ class in the Unreal Editor. Choose a parent class like `Actor` or `ActorComponent` based on your needs.
• UCLASS Macro: Use the `UCLASS()` macro to expose your C++ class to the Unreal Engine reflection system, making it accessible from Blueprints.
• UPROPERTY Macro: Use the `UPROPERTY()` macro to expose variables to Blueprints. You can control how these variables are exposed (e.g., editable in the editor, visible only in Blueprints).
• UFUNCTION Macro: Use the `UFUNCTION()` macro to expose C++ functions to Blueprints. Specify the `BlueprintCallable` specifier to make the function callable from a Blueprint graph.
• Compile and Refresh: After making changes to your C++ code, compile the project and refresh the Blueprint editor to see the changes.

Here’s a simple example:

#pragma once

#include "CoreMinimal.h"
#include "GameFramework/Actor.h"
#include "MyActor.generated.h"

UCLASS()
class MYPROJECT_API AMyActor : public AActor
{
	GENERATED_BODY()

public:	
	// Sets default values for this actor's properties
	AMyActor();

protected:
	// Called when the game starts or when spawned
	virtual void BeginPlay() override;

public:	
	// Called every frame
	virtual void Tick(float DeltaTime) override;

	// Expose a variable to Blueprints
	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = "MyCategory")
	float MyFloatValue;

	// Expose a function to Blueprints
	UFUNCTION(BlueprintCallable, Category = "MyCategory")
	void MyBlueprintFunction();
};
  

#include "MyActor.h"

AMyActor::AMyActor()
{
	// Set this actor to call Tick() every frame.  You can turn this off to improve performance if you don't need it.
	PrimaryActorTick.bCanEverTick = true;
	MyFloatValue = 0.0f;
}

void AMyActor::BeginPlay()
{
	Super::BeginPlay();
	
}

void AMyActor::Tick(float DeltaTime)
{
	Super::Tick(DeltaTime);

}

void AMyActor::MyBlueprintFunction()
{
	// Do something interesting here!
	UE_LOG(LogTemp, Warning, TEXT("MyBlueprintFunction called from Blueprint!"));
}
  

Creating Custom Blueprint Nodes for Efficiency ✨

Sometimes, you need more than just simple function calls. Creating custom Blueprint nodes allows you to encapsulate complex C++ logic into reusable nodes within the Blueprint editor, improving the visual clarity and reusability of your game logic.

• Define the Node’s Functionality: Create a C++ function that performs the desired operation. Make sure to use the `BlueprintPure` or `BlueprintCallable` specifiers in the `UFUNCTION` macro, depending on whether the node should have execution pins.
• Specifying Node Appearance: Use the `DisplayName` and `Category` specifiers in the `UFUNCTION` macro to control how the node appears in the Blueprint editor.
• Using `UKismetCompilerContext`: For more advanced nodes that need to manipulate the Blueprint graph, you can use the `UKismetCompilerContext` class.
• Custom Node Implementation: You can also create custom node implementations by inheriting from `UKismetNodeInfo`.

Example of a Blueprint Pure function:

UFUNCTION(BlueprintPure, Category = "MyCategory", DisplayName = "Add Floats")
static float AddFloats(float A, float B);
  

float AMyActor::AddFloats(float A, float B)
{
	return A + B;
}
  

Optimizing Data Handling for Performance 📈

Efficient data handling is crucial for game performance. When passing data between C++ and Blueprints, consider the performance implications of different data types and how data is copied.

• Use Primitive Types: Use primitive data types (e.g., `int`, `float`, `bool`) whenever possible, as they are generally more efficient to pass between C++ and Blueprints than complex objects.
• Pass by Reference: For large data structures, consider passing them by reference (using `&`) to avoid unnecessary copying. However, be careful when modifying data passed by reference, as it can have unintended side effects.
• Use Structures: Create custom structures (`USTRUCT`) to group related data together. This can improve the organization and readability of your code, and can also improve performance by reducing the number of individual parameters passed between C++ and Blueprints.
• Avoid String Conversions: String conversions can be expensive. Try to minimize the number of string conversions between C++ and Blueprints.

Example of passing by reference:

UFUNCTION(BlueprintCallable, Category = "MyCategory")
void UpdateArray(TArray& MyArray);
  

Leveraging C++ for AI and Pathfinding 💡

Artificial intelligence (AI) and pathfinding algorithms often require significant computational power. Implementing these systems in C++ can dramatically improve performance compared to implementing them entirely in Blueprints.

• Navigation Mesh Generation: Use C++ to generate and manage navigation meshes. The Unreal Engine provides a powerful navigation system that can be accessed and extended from C++.
• AI Behavior Trees: Create custom AI behavior tree tasks in C++ to handle complex AI logic. This can significantly improve the performance of your AI characters.
• Pathfinding Algorithms: Implement custom pathfinding algorithms in C++ to optimize pathfinding for specific scenarios. For example, you might implement an A* search algorithm that is tailored to the specific requirements of your game.
• Parallel Processing: Use multi-threading in C++ to perform AI and pathfinding calculations in parallel, further improving performance.

Example AI task:

#pragma once

#include "CoreMinimal.h"
#include "BehaviorTree/BTTaskNode.h"
#include "BTTask_FindRandomLocation.generated.h"

/**
 * 
 */
UCLASS()
class MYPROJECT_API UBTTask_FindRandomLocation : public UBTTaskNode
{
	GENERATED_BODY()
	
public:
	UBTTask_FindRandomLocation();

protected:

	virtual EBTNodeResult::Type ExecuteTask(UBehaviorTreeComponent& OwnerComp, uint8* NodeMemory) override;
};
  

Debugging and Profiling C++ Code in Unreal Engine ✅

Debugging and profiling are essential for identifying and resolving performance issues in your C++ code. Unreal Engine provides a variety of tools for debugging and profiling, including the Visual Studio debugger and the Unreal Insights tool.

• Visual Studio Debugger: Use the Visual Studio debugger to step through your C++ code, inspect variables, and set breakpoints.
• Unreal Insights: Use Unreal Insights to profile your game’s performance and identify bottlenecks. Unreal Insights provides detailed information about CPU and GPU usage, memory allocation, and other performance metrics.
• UE_LOG: Use the `UE_LOG` macro to print debug messages to the output log. This can be helpful for tracking the execution of your code and identifying errors.
• Assertions: Use assertions to check for unexpected conditions in your code. Assertions can help you catch errors early in the development process.

Example UE_LOG:

UE_LOG(LogTemp, Warning, TEXT("Value of MyFloatValue: %f"), MyFloatValue);
  

FAQ ❓

Why should I use C++ instead of Blueprints?

While Blueprints are great for visual scripting and rapid prototyping, C++ offers better performance and more control over low-level details. When you need to optimize performance-critical sections of your game or implement complex algorithms, C++ is the way to go. In some cases you will be able to reduce the overhead of Blueprint logic by 50 – 70%.

How do I call a C++ function from a Blueprint?

To call a C++ function from a Blueprint, you need to use the `UFUNCTION` macro with the `BlueprintCallable` specifier. This tells the Unreal Engine that the function can be called from a Blueprint graph. You also may want to declare the function static if you are calling it from a utility class.

What are some common performance bottlenecks in Unreal Engine games?

Common performance bottlenecks include excessive draw calls, inefficient data structures, and complex calculations performed every frame. Using C++ to optimize these areas can significantly improve your game’s performance. Also, consider using DoHost https://dohost.us hosting services for your server backend.

Conclusion

Integrating C++ with Blueprints is a powerful technique for unlocking the full potential of Unreal Engine. By moving performance-critical logic to C++, you can optimize your game’s performance and create more complex and engaging experiences. Embrace the power of C++ extending Blueprints Unreal Engine to create games that run smoothly and look stunning. Experiment, iterate, and continuously refine your approach to find the best balance between visual scripting and compiled code. With practice, you’ll be able to write code with ease, and improve your game’s performance. ✅

Tags

C++, Unreal Engine, Blueprints, Performance, Game Development

Meta Description

Supercharge your Unreal Engine projects! Learn how C++ extending Blueprints Unreal Engine boosts performance and unlocks advanced gameplay features. Dive in now!