Mercurial > gemma
view pkg/mesh/strtree.go @ 5342:08dc7e5de1f5 extented-report
fixing linting errors
author | Thomas Junk <thomas.junk@intevation.de> |
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date | Fri, 18 Jun 2021 12:05:57 +0200 |
parents | 01b593ea2311 |
children | 5f47eeea988d |
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// This is Free Software under GNU Affero General Public License v >= 3.0 // without warranty, see README.md and license for details. // // SPDX-License-Identifier: AGPL-3.0-or-later // License-Filename: LICENSES/AGPL-3.0.txt // // Copyright (C) 2018 by via donau // – Österreichische Wasserstraßen-Gesellschaft mbH // Software engineering by Intevation GmbH // // Author(s): // * Sascha L. Teichmann <sascha.teichmann@intevation.de> package mesh import ( "bytes" "compress/gzip" "encoding/binary" "io" "log" "math" "sort" ) // STRTreeDefaultEntries is the default number of children per node and leaf. const STRTreeDefaultEntries = 8 // STRTree is a Sort Tile Recurse tree. type STRTree struct { // Entries is the total number of entries. Entries int // tin is a reference to the TIN this tree is build from. tin *Tin // index is the internal tree representation. index []int32 // bboxes are the bounding boxes used in nodes and leaves. bboxes []Box2D } // Vertical does a vertical cross cut from (x1, y1) to (x2, y2). func (s *STRTree) Vertical(x1, y1, x2, y2 float64, fn func(*Triangle)) { box := Box2D{ X1: math.Min(x1, x2), Y1: math.Min(y1, y2), X2: math.Max(x1, x2), Y2: math.Max(y1, y2), } // out of bounding box if box.X2 < s.tin.Min.X || s.tin.Max.X < box.X1 || box.Y2 < s.tin.Min.Y || s.tin.Max.Y < box.Y1 { return } line := NewPlane2D(x1, y1, x2, y2) vertices := s.tin.Vertices stack := []int32{s.index[0]} for len(stack) > 0 { top := stack[len(stack)-1] stack = stack[:len(stack)-1] if top > 0 { // node if b := s.bbox(top); b.Intersects(box) && b.IntersectsPlane(line) { n := s.index[top+1] stack = append(stack, s.index[top+2:top+2+n]...) } } else { // leaf top = -top - 1 if b := s.bbox(top); !b.Intersects(box) || !b.IntersectsPlane(line) { continue } n := s.index[top+1] for _, idx := range s.index[top+2 : top+2+n] { ti := s.tin.Triangles[idx] t := Triangle{ vertices[ti[0]], vertices[ti[1]], vertices[ti[2]], } v0 := line.Eval(t[0].X, t[0].Y) v1 := line.Eval(t[1].X, t[1].Y) v2 := line.Eval(t[2].X, t[2].Y) if onPlane(v0) || onPlane(v1) || onPlane(v2) || sides(sides(sides(0, v0), v1), v2) == 3 { fn(&t) } } } } } // Min return the minimum vertex of the TIN this tree is build from. func (s *STRTree) Min() Vertex { return s.tin.Min } // Max return the maximum vertex of the TIN this tree is build from. func (s *STRTree) Max() Vertex { return s.tin.Max } // EPSG return the EPSF code of the TIN this tree is build from. func (s *STRTree) EPSG() uint32 { return s.tin.EPSG } // Value returns the Z Value for a given X/Y point. // Second return value is false if the point is out of bound. func (s *STRTree) Value(x, y float64) (float64, bool) { if len(s.index) == 0 { return 0, false } stack := []int32{s.index[0]} vertices := s.tin.Vertices for len(stack) > 0 { top := stack[len(stack)-1] stack = stack[:len(stack)-1] if top > 0 { // node if s.bbox(top).Contains(x, y) { n := s.index[top+1] stack = append(stack, s.index[top+2:top+2+n]...) } } else { // leaf top = -top - 1 if !s.bbox(top).Contains(x, y) { continue } n := s.index[top+1] for _, idx := range s.index[top+2 : top+2+n] { ti := s.tin.Triangles[idx] t := Triangle{ vertices[ti[0]], vertices[ti[1]], vertices[ti[2]], } if t.Contains(x, y) { return t.Plane3D().Z(x, y), true } } } } return 0, false } // Build builds a tree for a given TIN. func (s *STRTree) Build(t *Tin) { if s.Entries == 0 { s.Entries = STRTreeDefaultEntries } s.tin = t all := make([]int32, len(t.Triangles)) for i := range all { all[i] = int32(i) } s.index = append(s.index, 0) root := s.build(all) s.index[0] = root } // BuildWithout builds a tree for a given TIN ignoring the triangles // with the indices given in the remove map. func (s *STRTree) BuildWithout(t *Tin, remove map[int32]struct{}) { if s.Entries == 0 { s.Entries = STRTreeDefaultEntries } s.tin = t all := make([]int32, 0, len(t.Triangles)-len(remove)) for i := 0; i < len(t.Triangles); i++ { idx := int32(i) if _, found := remove[idx]; !found { all = append(all, idx) } } s.index = append(s.index, 0) root := s.build(all) s.index[0] = root } // Clip returns the indices of the triangles of the TIN // which are not fully covered by the given polygon. func (s *STRTree) Clip(p *Polygon) map[int32]struct{} { removed := make(map[int32]struct{}) stack := []int32{s.index[0]} vertices := s.tin.Vertices for len(stack) > 0 { top := stack[len(stack)-1] stack = stack[:len(stack)-1] if top > 0 { // node switch p.IntersectionBox2D(s.bbox(top)) { case IntersectionInside: // all triangles are inside polygon case IntersectionOutSide: // all triangles are outside polygon s.allTriangles(top, removed) default: // mixed bag n := s.index[top+1] stack = append(stack, s.index[top+2:top+2+n]...) } } else { // leaf top = -top - 1 switch p.IntersectionBox2D(s.bbox(top)) { case IntersectionInside: // all triangles are inside polygon case IntersectionOutSide: // all triangles are outside polygon n := s.index[top+1] for _, idx := range s.index[top+2 : top+2+n] { removed[idx] = struct{}{} } default: n := s.index[top+1] for _, idx := range s.index[top+2 : top+2+n] { ti := s.tin.Triangles[idx] t := Triangle{ vertices[ti[0]], vertices[ti[1]], vertices[ti[2]], } if p.IntersectionWithTriangle(&t) != IntersectionInside { removed[idx] = struct{}{} } } } } } return removed } func (s *STRTree) serializeIndex(w io.Writer) error { if err := binary.Write(w, binary.LittleEndian, int32(len(s.index))); err != nil { return err } var buf [binary.MaxVarintLen32]byte var last int32 var written int for _, x := range s.index { delta := x - last n := binary.PutVarint(buf[:], int64(delta)) for p := buf[:n]; len(p) > 0; p = p[n:] { var err error if n, err = w.Write(p); err != nil { return err } written += n } last = x } log.Printf("info: compressed index in bytes: %d %.2f (%d %.2f)\n", written, float64(written)/(1024*1024), 4*len(s.index), float64(4*len(s.index))/(1024*1024), ) return nil } func (s *STRTree) serializeBBoxes(w io.Writer) (rr error) { if err := binary.Write(w, binary.LittleEndian, int32(len(s.bboxes))); err != nil { return err } var err error write := func(v float64) { if err == nil { err = binary.Write(w, binary.LittleEndian, math.Float64bits(v)) } } for _, box := range s.bboxes { write(box.X1) write(box.Y1) write(box.X2) write(box.Y2) } return err } // Bytes serializes this tree to a byte slice. func (s *STRTree) Bytes() ([]byte, error) { var buf bytes.Buffer w, err := gzip.NewWriterLevel(&buf, gzip.BestSpeed) if err != nil { return nil, err } if err := s.tin.serialize(w); err != nil { return nil, err } if err := binary.Write(w, binary.LittleEndian, uint8(s.Entries)); err != nil { return nil, err } if err := s.serializeIndex(w); err != nil { return nil, err } if err := s.serializeBBoxes(w); err != nil { return nil, err } if err := w.Close(); err != nil { return nil, err } return buf.Bytes(), nil } func (s *STRTree) allTriangles(pos int32, tris map[int32]struct{}) { stack := []int32{pos} for len(stack) > 0 { top := stack[len(stack)-1] stack = stack[:len(stack)-1] if top > 0 { // node n := s.index[top+1] stack = append(stack, s.index[top+2:top+2+n]...) } else { // leaf top = -top - 1 n := s.index[top+1] for _, idx := range s.index[top+2 : top+2+n] { tris[idx] = struct{}{} } } } } func (s *STRTree) build(items []int32) int32 { sort.Slice(items, func(i, j int) bool { ti := s.tin.Triangles[items[i]] tj := s.tin.Triangles[items[j]] return s.tin.Vertices[ti[0]].X < s.tin.Vertices[tj[0]].X }) P := int(math.Ceil(float64(len(items)) / float64(s.Entries))) S := int(math.Ceil(math.Sqrt(float64(P)))) slices := s.strSplit(items, S) leaves := s.strJoin( slices, S, func(i, j int32) bool { ti := s.tin.Triangles[i] tj := s.tin.Triangles[j] return s.tin.Vertices[ti[0]].Y < s.tin.Vertices[tj[0]].Y }, s.allocLeaf, ) return s.buildNodes(leaves) } func (s *STRTree) buildNodes(items []int32) int32 { if len(items) <= s.Entries { return s.allocNode(items) } sort.Slice(items, func(i, j int) bool { return s.bbox(items[i]).X1 < s.bbox(items[j]).X1 }) P := int(math.Ceil(float64(len(items)) / float64(s.Entries))) S := int(math.Ceil(math.Sqrt(float64(P)))) slices := s.strSplit(items, S) nodes := s.strJoin( slices, S, func(i, j int32) bool { return s.bbox(i).Y1 < s.bbox(j).Y1 }, s.allocNode, ) return s.buildNodes(nodes) } func (s *STRTree) bbox(idx int32) Box2D { if idx < 0 { // Don't care if leaf or node. idx = -idx - 1 } return s.bboxes[s.index[idx]] } func (s *STRTree) strSplit(items []int32, S int) [][]int32 { sm := S * s.Entries slices := make([][]int32, S) for i := range slices { var n int if l := len(items); l < sm { n = l } else { n = sm } slices[i] = items[:n] items = items[n:] } return slices } func (s *STRTree) strJoin( slices [][]int32, S int, less func(int32, int32) bool, alloc func([]int32) int32, ) []int32 { nodes := make([]int32, 0, S*S) for _, slice := range slices { sort.Slice(slice, func(i, j int) bool { return less(slice[i], slice[j]) }) for len(slice) > 0 { var n int if l := len(slice); l >= s.Entries { n = s.Entries } else { n = l } nodes = append(nodes, alloc(slice[:n])) slice = slice[n:] } } return nodes } func (s *STRTree) allocNode(items []int32) int32 { pos := len(s.index) s.index = append(s.index, 0, int32(len(items))) s.index = append(s.index, items...) if len(items) > 0 { box := s.bbox(items[0]) for i := 1; i < len(items); i++ { box = box.Union(s.bbox(items[i])) } s.index[pos] = int32(s.allocBBox(box)) } return int32(pos) } func (s *STRTree) allocBBox(box Box2D) int { pos := len(s.bboxes) s.bboxes = append(s.bboxes, box) return pos } func (s *STRTree) allocLeaf(items []int32) int32 { pos := len(s.index) s.index = append(s.index, 0, int32(len(items))) s.index = append(s.index, items...) if len(items) > 0 { vertices := s.tin.Vertices ti := s.tin.Triangles[items[0]] t := Triangle{ vertices[ti[0]], vertices[ti[1]], vertices[ti[2]], } box := t.BBox() for i := 1; i < len(items); i++ { it := items[i] ti := s.tin.Triangles[it] t := Triangle{ vertices[ti[0]], vertices[ti[1]], vertices[ti[2]], } box = box.Union(t.BBox()) } s.index[pos] = int32(s.allocBBox(box)) } return int32(-(pos + 1)) }