So, I bought 2 books about Opengl terrain programming. I understand most of the basic and advanced concepts there with the help of the book and their codes.
I used it on my engine and planning to put my engine in sourceforge. I didn't use most of the codes used by the book because it uses immediate mode which is really slow. So, I rewrite most of the codes and algorithm for building the vertices and drawing it with the use of vertex buffer array and buffers and managed to optimized the code and get a great performance.
Now, I'm just worried that they ( the author of that book ), sue me. lol.