Function getNextSplatSourceId

src/utils/splatFileSourcePolicy.ts:13–22

(
  sources: readonly SplatFileSource[],
  activeId: string | null
)

 * already in memory.
 */
export function getNextSplatSourceId(
  sources: readonly SplatFileSource[],
  activeId: string | null
): string | null {
  if (sources.length <= 1) {
    return null;
  }
  const activeIndex = activeId ? sources.findIndex((source) => source.id === activeId) : -1;
  return sources[(activeIndex + 1) % sources.length].id;
}

/** Find a splat source by id, path, or downloaded file name. */
export function findSplatSourceById(