1.1 What is Irrlicht? 

Irrlicht is an open source, cross platform, realtime 3D scene graph API written in C++. What does all this mean?

What's a scene graph?
(illustration of a scene graph)
explain nodes etc

What is an API?

An API, or application programming interface, is a collection of rules for communicating with a service. In our case, it's a collection of C++ header files that tell you how to use the Irrlicht library.

Irrlicht deals with the business of drawing 3D graphics, so it provides a rich set of interfaces that deal with loading, organising, saving and drawing them. Using it is as simple as saying "create a window (device), load some 3D objects (meshes), add them to the scene (as nodes), add a camera, then render the scene." [[http://irrlicht.sourceforge.net/tut001.html | [1] ]] It doesn't matter whether it runs on Windows, Linux or the PSP, or what file format the objects are in, the code is the same.

Cross platform and portable?

The IrrlichtDevice and IFileSystem interfaces provide all the things you'd normally ask the operating system for, so Irrlicht could be using a Windows or a MacOS IrrlichtDevice underneath and your code wouldn't change. If you wanted to port Irrlicht to a new platform, you'd just write a new subclass of IrrlichtDevice that deals with the platform's OS.

Explain video drivers.


What kind of open source?

The [[http://irrlicht.sf.net/license.html | Irrlicht Engine License]] is a liberal [[http://www.opensource.org | open source license]] based on the zlib license. Like the zlib license and unlike the (L)GPL it is not a copyleft license, so you are not forced to release your source code. You can't remove the license and copyright information from the source code, but you don't even need to credit Irrlicht in binary releases (you must still credit the JPEG group for the JPG loader if you use it).

Irrlicht is not a game engine.

If you want to use Irrlicht to make games you'll need some other libraries too, because Irrlicht only deals with graphics. There's no AI, audio or physics. You can find a list of useful libraries here (link)