Processing.js is going to be the easiest way to make an opengl-based Processing app run with WebGL. It will involve the least amount of modifications.  Here is an example of one I've done, however if your sketch is fairly complex you may find out that you aren't getting the performance you want. For instance, on that same sketch of mine, push 'w' and it will start filling the triangles of the mesh, and slow to a crawl. At that point it will become a more involved process to port over and I personally would recommend checking out  Three.js

thank you!
...when i open it in FF nothing shows up, exept white and the text around it....?
anyway i checked the links and read the refference, but its not yet clear to me how to use that .js with my processing sketches...?

lumicon, what version of Firefox are you using? It works fine for me with FF5, I doubt it will work for lower versions, as the introduction of WebGL is quite recent in FF. You can also try and see the page with Chrome.

yep. after restart works here in FF fine, ..sorry

WebGL, ah! i see, it's directly within the html page code! cool!
thank you!