Using Blueprints and C++ for Game Logic

Tutorial 2 of 5

1. Introduction

This tutorial is designed to guide you on how to effectively use Blueprints and C++ to create game logic in Unreal Engine. By the end of this tutorial, you'll be able to create and manipulate game objects using both Blueprints and C++, and understand how they integrate together.

Goals

  • Understand Blueprints and C++ integration in Unreal Engine
  • Create game logic using Blueprints and C++
  • Learn best practices for using Blueprints and C++

Prerequisites

  • Basic understanding of Unreal Engine
  • Basic knowledge of C++

2. Step-by-Step Guide

Unreal Engine provides two primary methods for creating game logic: C++ and Blueprint Visual Scripting system. Blueprints are node-based systems that are great for creating game-play elements, whereas C++ is more robust and allows for more control and flexibility.

Using Blueprints

Blueprints are a form of visual scripting that are used in Unreal Engine. They include a variety of uses such as AI scripting, basic game logic, and more.

  1. Open Unreal Engine and create a new Blueprint class.
  2. Select the type of class you want to create (e.g., Actor, Character, etc.)
  3. Once the Blueprint is open, you can start creating game logic by dragging nodes onto the graph and connecting them.

Using C++

To use C++ in Unreal, you need to create a new C++ class.

  1. In Unreal Engine, navigate to File >> New C++ Class.
  2. Choose the class type and give it a name.
  3. Once the class is created, you can open it in your code editor and start writing C++ code.

Integrating Blueprints and C++

You can call C++ functions from Blueprints. To do this, you need to create a C++ function and mark it as a UFUNCTION(). Then, you can call this function in your Blueprint.

3. Code Examples

Blueprint Example

In this example, we'll create a simple Blueprint that prints a message when the game starts.

  1. Create a new Blueprint class and make it an Actor.
  2. Open the Blueprint and create a new node in the Event Graph.
  3. Search for "Event Begin Play", connect it to a "Print String" node and type your message.

C++ Example

In this example, we'll create a C++ function and call it from a Blueprint.

// This is your .h file
UCLASS()
class YOURGAME_API AYourClass : public AActor
{
    GENERATED_BODY()

public:
    // This function will be callable in Blueprints
    UFUNCTION(BlueprintCallable, Category = "My Functions")
    void MyFunction();
};

// This is your .cpp file
void AYourClass::MyFunction()
{
    UE_LOG(LogTemp, Warning, TEXT("MyFunction was called!"));
}

4. Summary

  • Unreal Engine provides two methods for creating game logic: Blueprints and C++.
  • Blueprints are great for quickly creating game logic, while C++ allows for more control and flexibility.
  • C++ functions can be called from Blueprints by marking them with UFUNCTION().

5. Practice Exercises

  1. Create a Blueprint that moves an object when the game starts.
  2. Create a C++ function that changes the color of an object, and call it from a Blueprint.
  3. Create a C++ function that takes input from the player, and use it in a Blueprint to move an object.

Remember to experiment with what you've learned and try to create your own game logic. This is the best way to learn and improve your skills. Happy coding!