VertexColor shader

Hi guys,

I’ve have a really specific issue. Using vertex color I can paint meshes with any colors I want, and here is an example: pixel colors between vertices are interpolated and the result of the interpolation looks like this:
The question is next, can I write my own shader which will change an algorithm that calculates color for pixels in these triangles of three vertices taking their color as input parameters? For example, instead of linear interpolations I would like to use cubic or some other functional dependency in order to get different color results.

P.S.: In order not to get confused, I am talking not about the base color which you pass to the material, but I am talking about the exact Vertex Coloring which you can see while painting meshes using the RGB view, so in the material when you use “Vertex Color” function, you could get different values using different shaders.

Did you ever find a solution?