three.js - Does it have indexed coloring for vertices?

Question

I've started using three.js, and I know there is coloring on vertices in three.js, but I'm investigating whether there is some way in three.js or generally in WebGL to have indexed colors for vertices? For example I would restrict coloring from blue, over yellow to red on a scale from minimum to maximum value, based on some values i give to the vertex, and the gradient between two vertices must use that scale of indexed colors. The practical example would be use in Finite Element Method visualisation.

So, do you know how one might hack this?

Answer 1

Store the indices with the vertex, and pass them on to the fragment shader. In the fragment shader, use the interpolated index to do a lookup in a 1d(*) texture containing the color gradiënt.

(*) Note that WebGL doesn't actually support true 1d textures, the common approach is to use an Nx1 2D texture.