How is a game developed using a game engine?

[LiLo]

Hi,

I would like to know what are the general steps in producing a game using a game engine like Orgre, Panda3D, Irrlicht or Torque.

I have the impression that the developer uses the game editor to draw out the terrain, environments or the indoor scences and add the game's objects. Then a scripting language which the engine supports is used for scripting.

I have read the descriptions of the game engines on http://www.devmaster.net/engines/
and the engines has features like AI, collision detection, audio etc. How are these elements integrated into the game? Is it through clicking and selecting or do the developers have to script these features into the game?

And currently, I am using the Unreal editor to create unreal game levels. I'm also studying unreal script. Is this also called "developing a game using an engine" ?

[Grunt]

you are correct on all that. Some engines are just rendering engines like irrlicht where you have to add sound and physics from 3rd party libs. Basically to create a game they just create level from whatever level editor they use, and models from 3ds max or whatever.

[Jacob Roman]

Personally I prefer developing my own engine. You then would have total control on what you want out of it rather than relying on others. It takes a longer time to develope a game but it's usually worth it. If that thought alone was never done, we'd still be making games from the original Doom/Quake 1 engine.

[chemicalNova]

Technically its not scripting. Irrlicht I know, from experience, needs to be written in an actual programming language, not a scripting language. I doubt you'll find a 3D engine with actual scripting to complete every single task..

chem

[LiLo]

Thanks for the replies

So depending on the engine's capabilities, the developer has to either bring in 3rd party libraries into the game or modify the engine to build these capabilities into the engine using c++ or some lower level language?

And also, what is scripting in a game commonly used for?

[Merri]

Commonly to define what objects there are, to link graphics/3D models with objects, define object property values... generally depending on a game lots of customizability is moved from code to scripting to make modifying the game faster and easier so that one doesn't need to recompile the game executable just to change small things such as bullet shooting rate in the game.

[chemicalNova]

So depending on the engine's capabilities, the developer has to either bring in 3rd party libraries into the game or modify the engine to build these capabilities into the engine using c++ or some lower level language?

Engines don't have to be written in lower level languages (although that is the industry standard). Engines can be written in VB6 and Delphi also. The execution speed of these languages though, is what can make an engine seem luggish when you really get down to it. Engines don't have to use hardware either, they can be purely software through the use of the API (unlike DirectX/OpenGL). Many people find using a graphics library like DirectX or OpenGL to be easier though, since most of the work (when I say most, I don't mean its easier) is done for you. For example, writing an engine in DirectX will result in the framerate being sustained for you, whereas if you were to write an engine purely in a language of choice, you would have to handle the framerate cap yourself.

chem

[Spodi]

How fast the engine goes depends on how the programmer writes it, and not as much what language it is written in. You'll see more C++ engines since it is a more industrial language then VB or other higher-level languages. This does not mean, though, that the higher-level languages cant do the task.

[chemicalNova]

This argument has been made many times, by many different people . No matter how much you sugar coat it, if you were to undertake the huge task of writing a complete 3D engine, you would see a noticible difference in performance with VB. Sure, you can write a small 3D engine, consisting of nothing but a map loader and basic gameplay, and you would see no noticible difference between languages. Once you get into things like having a Sound Engine with alot of features, a full 3D engine, map loader, etc, you will end up seeing a big difference.

chem