do I give parts of my track a different appearance?
There are different ways to do this, but
one way is to use the built-in shader variable gl_PrimitiveID,
which is a unique number given to each primitive being rendered.
For example, maybe primitives 200 to 300
should be rendered differently in the fragment shader:
Can limit this effect to the
track only using a uniform
not render certain primitives, this can be done with calling glDrawElements