[quote name='Bacterius' timestamp='1350348048' post='4990568']
Heya, it's been forever since I worked with Tessendorf waves but I recommend [url="http://www.keithlantz.net/2011/10/ocean-simulation-part-one-using-the-discrete-fourier-transform/"]this website[/url], it shows how to generate the waves along with the normals using the FFT, code included. Note there are two parts! Or if you are not using the FFT method, there is a - admittedly rather arcane - description of the normal for Gerstner waves in this [url="http://http.developer.nvidia.com/GPUGems/gpugems_ch01.html"]GPU Gems[/url] article, have you looked at it?
If everything fails, you can always use good old finite difference approximation to evaluate the normal, which is a bit more expensive since you have to sample the wave multiple times, but at least is general-purpose.
Thanks, but... im a beginner. I got the gpu gems example working right. That sample is a bit more easy. Mine has a difference, the [b](K/k)[/b] * wave, and the movement both in XY and Z, not just the vertical (z for me). Its just a math thing.