In processing there is a function that creates directional light in 3D. But i wanna create the same effect in 2D. I think i need a vector and color info so i can create a shadow effect on a image.
Like this: 
The mouse becomes a point of light and when it moves around it changes the image creating a shadow effect on it.
I can't use function that are 3D like pointLight or directionalLight so any ideas where should i start?