index.js
function passId (trace, i, j) {
	let id = (trace.id != null ? trace.id : trace)
	let n = i
	let m = j
	let key = id << 16 | (n & 0xff) << 8 | m & 0xff

	return key
}
function passId (trace, i, j) {
	let id = (trace.id != null ? trace.id : trace)
	let n = i
	let m = j
	let key = id << 16 | (n & 0xff) << 8 | m & 0xff

	return key
}
function passId ( trace , i , j ) { let id = ( trace . id != null ? trace . id : trace ) let n = i let m = j let key = id << 16 | ( n & 0xff ) << 8 | m & 0xff return key }
return pass corresponding to trace i- j- square
return pass corresponding to trace i - j - square