Game engine

In short: A game engine is a software toolkit that takes over the recurring tasks of game development: graphics, physics, sound, input, animation, network and tools. Developers build their own game on it.

In more detail: Instead of programming graphics, collision and sound anew each time, you use an engine. It consists of a runtime (which executes the game) and usually an editor (for designing scenes, objects, materials).

In Depth

Components:

• Renderer: Draws 2D/3D with shaders, light, shadows, ray tracing.
• Physics engine: Collisions, gravity, vehicles, cloth.
• Audio: 3D sound, mixer.
• Input: Keyboard, gamepad, touch, VR controllers.
• Animation: Skeletons, state machines, transitions.
• Scenes/objects: Scene graph, component system (entity-component-system).
• Scripting: C# (Unity), C++/Blueprints (Unreal), GDScript (Godot).
• Network, AI (pathfinding), asset management, export tools.

Well-known engines:

Engine	Language	Strengths	License
Unity	C#	Mobile, indie, 2D and 3D, huge community	free up to a revenue limit, then paid
Unreal Engine	C++ / Blueprints	Top graphics, AAA games, film	royalty by revenue
Godot	GDScript, C#	Light, open source, strong 2D	MIT (free)
GameMaker, Construct	script / visual	Simple 2D games	commercial
Own engines	C/C++	Full control (Source, id Tech, Frostbite)	internal

Export targets: PC, consoles, iOS/Android, web (WebGL/WebGPU), VR/AR.

Pros and cons:

• Saves years of groundwork, proven tools, platform export.
• Disadvantages: License terms, fixed framework, overhead, learning curve.

Other fields: Architectural visualization, simulations, real-time film production, training, digital twins.

See also: Unity, Shaders, 3D modeling