globalCellOf function
Resolves a piece's relative track position (must be in 0..50, i.e. on
the shared path — see LudoPiece.isOnSharedPath) for playerIndex to an
absolute index into kPathCells.
Implementation
int globalCellOf(int playerIndex, int trackPosition) {
return (kStartIndices[playerIndex] + trackPosition) % kPathCells.length;
}