I am developing a little game. I need an A star path-finding algorithm for enemies who follow the player. I have already learned and tested a path-finding algorithm, but it works with fixed-size array.

How can I turn an open world into a fixed-size array? I am developing with Irrlicht engine 1.6 version. I know that it is a quite old, but it is the only engine which works for me in Windows XP.

Here is my A star path-finding code that works in a 2D grid.

Additionally ,if it is needed, Here there is a link to the work I have done with Irrlicht: Just a walking person.

Please put media folder in your C:\ drive. Thanks.