How to Make a Game Engine

How to Make a Game Engine

Creating a game engine is an extensive task requiring in-depth knowledge in various areas like computer graphics, physics simulation, audio processing, and programming. This guide will provide a broad overview of the process involved in creating a game engine.

Understanding Game Engines

Game engines are software frameworks designed to facilitate video game development and creation. They manage and handle several tasks, such as rendering graphics, simulating physics, handling input, and managing memory. Some popular examples include Unreal Engine, Unity, and Godot.

Creating a game engine can be an enlightening and educational experience that can help you gain a deeper understanding of how games function at a fundamental level. However, it’s also a massive undertaking. Here is a simplified breakdown of the main components of a game engine and how they can be created.

Programming Language

First, you must choose the programming language to write your game engine. C++ is a popular choice due to its performance and control. However, languages like C# and Python can also be used.


Graphics are a crucial part of a game engine. You’ll need to understand computer graphics principles and work with a Graphics API such as OpenGL, DirectX, or Vulkan. These APIs enable the game to communicate with the GPU.

Rendering is a primary task of the graphics component, and you’ll need to build systems for drawing 2D or 3D objects. This involves understanding vector mathematics, matrices, transformations, and lighting models.


Game engines often include a physics engine for simulating realistic motion and collisions. You’ll need to implement physics concepts like gravity, collision detection, and response algorithms. This aspect often involves mathematics, specifically calculus and linear algebra.


Sound is an important part of the gaming experience. Your game engine should be able to play back audio files and adjust their properties like volume and pitch. You might use audio APIs like OpenAL for this purpose.


Your game engine should be able to process input from the user. This could be keyboard, mouse, or gamepad input. You need to design the system such that the game objects respond appropriately to these inputs.


All these components must be brought together in a cohesive and efficient manner. You must design the architecture of your game engine. This might include aspects like game object management, scene management, resource loading and unloading, and more.

Building Your Game Engine

Now that we’ve explored the components of a game engine let’s delve into the steps involved in creating one.

Education and Preparation: Game engine development requires a strong background in programming and mathematics. You’ll need to understand data structures, algorithms, and object-oriented programming. Knowledge of computer graphics and physics is also vital. Before beginning the project, familiarize yourself with these topics.

Design Your Engine: Plan your game engine. Decide which features you want to include and create an architecture that brings all these components together. You might choose to follow the entity-component-system architecture that is popular in game engines.

Graphics and Rendering: Learn to use a Graphics API to draw objects on the screen. Start by rendering simple 2D shapes and gradually move to more complex 3D objects.

Physics: Implement a system to simulate motion and collisions. For a simple engine, basic rectangle or sphere-based collisions might be sufficient.

Audio: Add the ability to play back audio files. This could be background music or sound effects triggered by specific events in the game.

Input: Develop a system for handling user input. This system should be flexible and adaptable for various types of games.

Testing: Ensure to test your game engine regularly. Every component should be tested individually, and the engine as a whole should be tested by creating small games with it Testing is a crucial phase in game engine development. It involves verifying and validating that the engine and its components function as expected, identifying any bugs or issues, and fixing them.

Unit Testing

Begin by testing the smallest units of your game engine – the individual components. This is known as unit testing. Here are a few examples of what unit tests may look like:

Graphics: You could test your rendering system by attempting to render a simple object and checking if it appears correctly on the screen. You might also test your shaders by applying different shaders to an object and verifying the output.

Physics: For your physics engine, you might test the collision detection system by simulating two objects colliding and checking if the system accurately detects the collision.

Audio: You could test your audio system by playing an audio file and checking if the sound is played correctly, with proper controls for volume and pitch.

Input: Test your input system by simulating key presses or mouse movements and verifying if the input is correctly recognized and processed.

Unit tests should cover every method and function in your code to ensure that all parts of your game engine are functioning as expected.

Integration Testing

Once you have verified that the individual components work correctly, you need to ensure they work well together. This is known as integration testing. For example, when an object collides with another in your game, the physics engine should detect the collision, and an appropriate sound effect should be played by the audio system. Similarly, user input should cause corresponding changes in the game state.

System Testing

System testing involves testing the game engine as a whole. This is usually done by creating a small game using the engine. The game should use most, if not all, of the engine’s features. If the game runs smoothly, it’s a good indication that your engine is functioning well.

Keep in mind that testing is not a one-time process but rather an ongoing one. You should continually test your game engine during development, particularly after making changes or additions to the code.

Debugging and Issue Resolution

During testing, you’ll likely encounter bugs or issues. Debugging involves identifying the cause of these problems and fixing them. For this, a good understanding of your code and debugging tools is crucial.

Remember to not only fix issues but also understand why they occurred in the first place. This will help prevent similar problems in the future and improve your skills as a game engine developer.

Performance Testing

Performance is critical for a game engine. Your engine should be able to run games smoothly without consuming excessive resources. Performance testing involves evaluating the speed, responsiveness, and stability of your game engine.

You might also need to carry out stress testing, which involves testing the engine under heavy loads, such as complex scenes with many game objects.

In conclusion, building a game engine involves much more than just writing code. It requires an understanding of various domains, careful planning, and rigorous testing. However, the knowledge and experience gained from building a game engine from scratch can be invaluable, and it’s an excellent project for anyone looking to deepen their understanding of game development.