Is it possible to develop a grasshopper plugin using processing sketch.
Directly porting your Processing sketch to a Grasshopper component is probably not possible.
However, translating the idea of the script to GH-compliant Python, C#, or VB, should be pretty straightforward, especially if you already have some programming knowledge from Processing.
What Processing offers the user straight out of the box, that Rhino/Grasshopper doesn’t, is an animation framework (e.g. void setup, void draw, camera controls) and a far easier display pipeline (e.g. colours, materials, line weights, etc.).
That being said, it is quite possible to achieve similar results though. It might just be more tedious.
Depending on what you want to achieve, you could also work with both. Simply do one part in Rhino/Grasshopper and export it to Processing to continue, or vis versa.
What is it that you are after exactly?
C# is pretty close to Processing. The bridging doesn’t make much sense now. Gh is way more powerful than earlier where it had limitations and people had to use UDP ports with other platforms to compensate.
If its converting to sounds, robotics,or webcam stuff checkout “Firefly”