Having read Tessendor's paper on ocean rendering, i am still a bit confused by the paper:
https://people.cs.clemson.edu/~jtessen/reports/papers_files/coursenotes2004.pdf

Is it a forward FFT or an inverse FFT ? It's not clear to me.

The exp function has positive coefficient making me think it's inverse but in the paper it does not divide by the bin count … 1/N like i typically see for the iFFT… can some one explain which one it is, i am a bit lost.

@CelticSir When I been making ocean water using this paper, I used nVidia Ocean example and nVidia FFT example of Butterfly method of FFT, it helped a lot.