A system that contains everything you need to create a game without *needing* to write any more code. So things that are often missing from 'engines' are :
- Skinning support combined with skeletal/weighted model format support with a minimum of exporters for 3DS and Blender.
- Path finding and steering algorithms for 3D environments with full physics integration.
- Abstracted game mechanics IE concepts such as projectiles, vehicles, pickups being implemented and customizable.
- An event structure separate from scripting that allows the chaining of events, IE collide, particles, noise, decrement variable (Ie health)
- programmable particle systems tied into events / scripting.
- Abstracted input and focus schemes for controller input. IE the ability to have a mouse cursor style RPG and a mouse controlled FPS from the same sub-system.
- Full support for variable digital controllers (IE analogue sticks) tied into input mechanism to allow for touch/mouse/stick control of the same input channel.
- Templated and scriptable finite state machines and decision trees tied into every relevant part of the engine.
Unreal is a game engine, ID Tech etc. You can pick them up, create some resources and have a playable game without writing any code.
You may want or need to add extra code to a game engine, IE the many custom versions of the Quake engine. But if you can't make a game with a system without writing extra code then it's not a 'game engine'.
It's middleware, graphics engines, whole frameworks, but not a game engine.
Another way of putting it would be to say that game engines are whole games that are setup to be customizable. The more customizable, the more the engine is used in the industry.
(not strictly accurate, unity isn't quite like this for example but as already stated, you can make games in unity using nothing but a mouse. You don't have to write anything substantial, just plug things together)
Reply With Quote
Bookmarks