Hello,

  You could certainly follow that approach. However, if you are just starting this now, it might be worth developing an atlas to work with NiiVue rather than MRIcroGL. As NiiVue has been adopted by many teams (AFNI, FSL, FreeSurfer, OpenNeuro), this can ease sharing. 

The relevant description of the NiiVue labels is here:

https://github.com/niivue/niivue/blob/main/docs/development-notes/colormaps.md#atlases-and-labeled-images

The live demo lets you apply your own colormap by inserting it into the text entry on the web page:

https://niivue.github.io/niivue/features/segment.html

A nice feature of NiiVue, is that it supports both voxels and labels, so your solution will work for both representations.