How to do parallax mapping Realbasic OpenGL

I’ve been studying bump mapping techniques and have learned about displacement mapping, normal mapping and parallax mapping. I really like the depth of feel that parallax mapping provides.

My understanding is that it does not change the geometry but gives the illusion of depth on the surface that will be good enough for the game I’m designing.

Does anyone have any sample code at all or instructions showing the parallax technique and how it works. I’m having a very hard time understanding what it’s really doing?

I understand normal mapping adjusts the normals on the texture to make it appear darker in areas to create the illusion of depth, but I’m not sure what parallax is doing? I think it’s something similar with the normals as well but I need help to understand.

Thank you