First I would like to congratulate the author of the Document "Realtime Synthesis of Eroded Fractal Terrain for Use in Computer Games". I learnt very much things.
So I started to generate my own heightmaps using technics presented on the document. Actually I'm generating heightmaps with the diamond square method, voronoi diagrams, pertubation filter and then thermal erosion. Generated heightmaps look good but when i render them in 3D, I have a huge "visual" problem.
It's look like stairs...
I'm using double for heightmap's height value between 0..1. When I generate bitmaps, I multiply theses values per 255 to get the final color in greyscale so I cast my double as int. Maybe that's the problem.. If someone can help me, that would be great because I'm a bit lost this time