thanks! this is almost the solution, i wonder though, in that box you use multiple lines with instanceStart and instanceEnd, whereas i have a single lineSegments ([0,0,0, 1,1,0, 2,0,0, 1,-1,0]). what does instanceStart and End mean exactly in my case, since my LineGeometry has four vectors?
AFAIK, FatLines in its core uses instancing. So each segment is an instance of a plane (I think), that has instanced values for its start and its end. When you create fat lines, it internally creates an instanced mesh or a mesh with InstancedBufferGeometry (not sure which one).
How it processed in shaders is something of the black magic for me in general, though I can figure out of how some parts of it work and create funny things, like this: FatLines + noise
or this (there is no forum post of it yet, but I’ve got it on a plan)
moving more than the first point seems to be really tricky. do you think it makes even sense to mess with internals or should i just call setPositions every frame, though i seems to me it would re-create buffers in that case, seems expensive and wasteful …