confusing fullscreen mode problem - need help

I have recently been creating a 3D terrain engine, using heightmapping and multitexturing. It was all going fine, I managed to make the map loading and rendering code, and started the basis of a terrain texture generator. But now, when I tried to run the program on fullscreen, it looks as though the hills have been built out of layers -> see the screenshot to understand. It has never happened to me before, and I have made a small 3D engine. If someone has had this problem before, and fixed it, or knows what is I desperatly need some help. THe code is at the bottom. Screenshots: Windowed mode- Fullscreen - Executable + bitmaps (basically the program without code): here Code + DevCpp project file (but no program): here Source code files: camera.cpp - opengl camera glwindow.cpp - my own oo basecode hmap_load.cpp - heightmap loading code main.cpp - main program, contains render code bitmap.cpp - bitmap loading / saving code terrain_tex.cpp - half finished terrain texture generator -> currently takes heights and turns them into a color texture. Anyways, please help me! PS- by the way, the site i hosted the files on takes a long time download from -> and the bitmaps + program zip is quite large