Function closestPointOnTri

closestPointOnTri(
    p: [number, number, number],
    a: [number, number, number],
    b: [number, number, number],
    c: [number, number, number],
): ClosestPoint
Closest point on triangle (a,b,c) to query point p, with squared distance.

Direct TS port of the WGSL routine in sdf_bake.wgsl (Ericson "Real-Time Collision Detection" §5.1.5). Kept in lockstep with the shader so the CPU helper can act as an oracle in tests.
Parameters
- p: [number, number, number]
- a: [number, number, number]
- b: [number, number, number]
- c: [number, number, number]
Returns ClosestPoint
- Defined in src/sdf/sdf_math.ts:63