Elevators (white) between Earth and a Tethered Ring
I'm developing a Three.js model of the Tethered Ring, which is a space access and transportation infrastructure project. I would like to add elevator cables (white) between the Tethered Ring and Earth only where there is land. I'd like to do this by:
- Retrieving the color of the Earth's texture where the elevator cable's "ray" intersects the front face of the Earth's texture,
- Comparing that color to blue, and
- Adding the cable object only where the color is "not blue".
I would be very appreciative if someone could provide sample code for step 1!
(Note: This earlier post from 6 years ago gives clues but doesn't go into sufficient detail. ref: ThreeJS How to pick the intersection point color of an object)