I've been making some simple programs with opengl and I think I have enought experienced with it. So recently I tried to make my own game engine. But it seems to be something very complex.

I've heard that irrlicht provides everything that a game engine should have and there's an editor for it too. So I wanna know where to start learning it and dig into it's source code to add some of my custom functions. Is there any tutorials that talks about these things?

Check this out: http://fabiensanglard.net/

He goes into detail examining game engine source code. If you do the same stuff you're on the right track.

Download the irrlicht sdk, it is full of examples showing every basic (and not) aspect of the engine.

Download the irrlicht sdk, it is full of examples showing every basic (and not) aspect of the engine.

I can only find examples about how to use it but nothing about something that gets me in its source code or architecture

Download the irrlicht sdk, it is full of examples showing every basic (and not) aspect of the engine.

I can only find examples about how to use it but nothing about something that gets me in its source code or architecture

http://irrlicht.sourceforge.net/downloads/

Downloads

This page contains links to all recent downloadable files of Irrlicht.

Irrlicht SDK 1.8.1

Software development kit required to develop applications with the Irrlicht engine. Included is the documentation, the source code and a precompiled version of the engine, tutorials, tools, exporters and a cool interactive demo.

irrlicht-1.8.1.zip (23MB)

or: https://sourceforge.net/projects/irrlicht/files/Irrlicht%20SDK/1.8/1.8.1/irrlicht-1.8.1.zip/download

The download says it contains the source code. Did you look for it in the latest download?

Download the irrlicht sdk, it is full of examples showing every basic (and not) aspect of the engine.

I can only find examples about how to use it but nothing about something that gets me in its source code or architecture

So you want some paper explaining how irrlicht is built? I don't know of any, but sdk contains source code and the doxygen doc is pretty good. You can easily start from there and open the .h and .cpp files to look inside on how things have been done.

Download the irrlicht sdk, it is full of examples showing every basic (and not) aspect of the engine.

I can only find examples about how to use it but nothing about something that gets me in its source code or architecture

So you want some paper explaining how irrlicht is built? I don't know of any, but sdk contains source code and the doxygen doc is pretty good. You can easily start from there and open the .h and .cpp files to look inside on how things have been done.

i don't want to get into such a huge project without any guidance

There is also a good book for Irrlicht gameplay programming : http://www.amazon.com/Irrlicht-Realtime-Engine-Beginners-Guide/dp/1849513988