This demo is based on two shaders—one for visible scene, second for hidden pickingScene with ID colours
1: [0, 0, 1]
65: [0, 0, 65]
543: [0, 2, 31]
6356: [0, 24, 212]
So, the maximus ID’s you can have 16,777,215 + background colour.
While picking function looks through second hidden scene, you can use any colours in main scene, including ID tones.