There is an app named Funny Face Effects on play store.
I am trying to achieve the effect in which when a user moves the finger on image, pixels under the finger in certain radius shifts in that direction. It feels like moving a cloth with a finger or moving some thick paste with the finger. I could not find a proper name but I think it is called smudge.
After searching and trying I found that I can achieve this with GPUImage library.This library uses OpenGL fragment shader to apply some effect on image. I tried this but to get the continuous effect I have to save each finger position(each point on line) and apply filter for each point which is not feasible and it stuck after drawing more lines.
How to achieve this effect with OpenGL-ES? It will be good if code is provided but just the idea of implementation will also work. Thank you.
