Hi all! I''ve got the textured heightfield terrain example from "openGL Game Programming" book (chapter 8) in which there is a small bitmap 32x32 heightmap. My problem is that I can not understand why the whole terrain shape changes when I modify (Adobe Photoshop) the small bitmap 32x32. I changed only one pixel colour in the whole bitmap and the whole terrain got very messy. Actually there was almost no terrain at all, just on the edges there was a few square blocks from the whole terrain left. Why a small change makes a huge difference?????? Does anyone know what is going on? THX!!

make sure the image is in the same format as it was originally.

yes! I was saving in a wrong file format ! Now I know what was going on!! Silly misatke!! Sorry!
Thanks all!!!!!