+
+ log.Infof("renumbering variants for tags %d-%d", tagstart, tagend)
+ variantRemap := make([][]tileVariantID, tagend-tagstart)
+ var wg sync.WaitGroup
+ for tag, variants := range seq {
+ tag, variants := tag, variants
+ wg.Add(1)
+ go func() {
+ defer wg.Done()
+ count := make([]tileVariantID, len(variants))
+ for _, cg := range cgs {
+ idx := (tag - tagstart) * 2
+ count[cg.Variants[idx]]++
+ count[cg.Variants[idx+1]]++
+ }
+ ranked := make([]tileVariantID, len(variants))
+ for i := range ranked {
+ ranked[i] = tileVariantID(i)
+ }
+ sort.Slice(ranked, func(i, j int) bool {
+ if i == 0 {
+ return true // leave ranked[0] at position 0, unused
+ } else if j == 0 {
+ return false // ditto
+ }
+ if cri, crj := count[ranked[i]], count[ranked[j]]; cri != crj {
+ return cri > crj
+ } else {
+ return bytes.Compare(variants[ranked[i]].Blake2b[:], variants[ranked[j]].Blake2b[:]) < 0
+ }
+ })
+ remap := make([]tileVariantID, len(ranked))
+ for i, r := range ranked {
+ remap[r] = tileVariantID(i)
+ }
+ variantRemap[tag-tagstart] = remap
+ }()
+ }
+ wg.Wait()