VIDEOGAMES ENGINES

WHAT IS A GAME ENGINE?

A game engine, also known as a game architecture, game framework or gameframe, is a software-development environment designed for people to build video games. Developers use game engines to construct games for consoles, mobile devices, and personal computers. The core functionality typically provided by a game engine includes a rendering engine ("renderer") for 2D or 3D graphics, a physics engine or collision detection (and collision response), sound, scripting, animation, artificial intelligence, networking, streaming, memory management, threading, localization support, scene graph, and may include video support for cinematics. Implementers often economize on the process of game development by reusing/adapting, in large part, the same game engine to produce different games or to aid in porting games to multiple platforms.

WHY ARE THEY IMPORTANT?

Game engines are reusable components developers use to build the framework of the game. This gives them more time to focus on the unique elements like character models, textures, how objects interact, etc. If everyone made their games from scratch without the help of excellent game engines, games would take longer and be more difficult to make.

VIDEO HOW GAME ENGINES WORK

COMPONENTS

Main game program
The actual game logic has to be implemented by some algorithms.

Rendering engine
The rendering engine generates animated 3D graphics by any of a number of methods. 

Instead of being programmed and compiled to be executed on the CPU or GPU directly, most often rendering engines are built upon one or multiple rendering application programming interfaces (APIs), such as Direct3D, OpenGL, or Vulkan which provide a software abstraction of the graphics processing unit (GPU). Low-level libraries such as DirectX, Simple DirectMedia Layer (SDL), and OpenGL are also commonly used in games as they provide hardware-independent access to other computer hardware such as input devices (mouse, keyboard, and joystick), network cards, and sound cards. Before hardware-accelerated 3D graphics, software renderers had been used. Software rendering is still used in some modeling tools or for still-rendered images when visual accuracy is valued over real-time performance (frames-per-second) or when the computer hardware does not meet needs such as shader support.

With the advent of hardware accelerated physics processing, various physics APIs such as PAL and the physics extensions of COLLADA became available to provide a software abstraction of the physics processing unit of different middleware providers and console platforms.

Game engines can be written in any programming language like C++, C or Java, though each language is structurally different and may provide different levels of access to specific functions. Often a Scripting Language like Javascript / ECMAScript gets added as the second layer to speed up the development.

Audio engine
The audio engine is the component which consists of algorithms related to the loading, modifying and output of sound through the client's speaker system. At a minimum it must be able to load, decompress and play sound files. More advanced audio engines can calculate and produce such things as Doppler effects, echoes, pitch/amplitude adjustments, oscillation, etc. It can perform calculations on the CPU, or on a dedicated ASIC. Abstraction APIs, such as OpenAL, SDL audio, XAudio 2, Web Audio, etc. are available.

Physics engine
The physics engine is responsible for emulating the laws of physics realistically within the application. Specifically, it provides a set of functions for simulating physical forces and collisions, acting on the various objects within the game at run time.

Artificial intelligence
The AI is usually outsourced from the main game program into a special module to be designed and written by software engineers with specialist knowledge. Most games will implement very different AI systems, and thus, AI is considered to be specific to the particular game for which it is created. Many modern game engines come packaged with search algorithms such as A-star and subroutines for baking level geometry into a Navmesh which can help speed up the process of scripting AI behavior.

VIDEOGAMES ENGINES

MOBILE GAMES ENGINES

OPEN SOURCE GAME ENGINES