Mercurial > gemma
view pkg/octree/builder.go @ 1234:1a5564655f2a
refac: Sidebar reorganized
In order to make context switches between administrative tasks
which are map related and those which are system related, we now have
a category "administration" and "systemadministration".
The Riverbedmorphology does nothing than display the map, so it is
renamed to that (map). In case the context of "systemadministration"
is chosen, the "map" brings you just back to the map.
author | Thomas Junk <thomas.junk@intevation.de> |
---|---|
date | Tue, 20 Nov 2018 09:54:53 +0100 |
parents | a244b18cb916 |
children | fbdd7c3cfeac |
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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 octree import ( "bytes" "encoding/binary" "io" "log" "github.com/golang/snappy" ) type Builder struct { t *Tin nodes int leaves int index []int32 } var cubes = [8][2]Vertex{ makeCube(0), makeCube(1), makeCube(2), makeCube(3), makeCube(4), makeCube(5), makeCube(6), makeCube(7), } func makeCube(i int) [2]Vertex { var d Vertex if i&1 == 1 { d.X = 0.5 } if i&2 == 2 { d.Y = 0.5 } if i&4 == 4 { d.Z = 0.5 } return [2]Vertex{ Vertex{0.0, 0.0, 0.0}.Add(d), Vertex{0.5, 0.5, 0.5}.Add(d), } } func NewBuilder(t *Tin) *Builder { return &Builder{t: t} } func (tb *Builder) Build() { triangles := make([]int32, len(tb.t.Triangles)) for i := range triangles { triangles[i] = int32(i) } tb.index = append(tb.index, 0) tb.buildRecursive(triangles, tb.t.Min, tb.t.Max, 0) tb.index[0] = int32(len(tb.index)) log.Printf("num nodes: %d\n", tb.index[0]) log.Printf("nodes: %d leaves: %d index %d\n", tb.nodes, tb.leaves, tb.index[0]) } func (tb *Builder) buildRecursive( triangles []int32, min, max Vertex, depth int, ) int32 { if len(triangles) <= 16 || depth > 8 { pos := len(tb.index) tb.index = append(tb.index, int32(len(triangles))) tb.index = append(tb.index, triangles...) //log.Printf("leaf entries: %d (%d)\n", len(triangles), depth) tb.leaves++ return int32(-(pos + 1)) } pos := len(tb.index) tb.index = append(tb.index, 0, 0, 0, 0, 0, 0, 0, 0) bbox := Interpolate(min, max) bboxes := make([][2]Vertex, len(cubes)) for i := range cubes { bboxes[i] = [2]Vertex{ bbox(cubes[i][0]), bbox(cubes[i][1]), } } var quandrants [8][]int32 for _, tri := range triangles { triangle := tb.t.Triangles[tri] v0 := tb.t.Vertices[triangle[0]] v1 := tb.t.Vertices[triangle[1]] v2 := tb.t.Vertices[triangle[2]] l := v0 l.Minimize(v1) l.Minimize(v2) h := v0 h.Maximize(v1) h.Maximize(v2) for i := range bboxes { if !(h.Less(bboxes[i][0]) || bboxes[i][1].Less(l)) { quandrants[i] = append(quandrants[i], tri) } } } for i := range quandrants { if len(quandrants[i]) > 0 { child := tb.buildRecursive( quandrants[i], bboxes[i][0], bboxes[i][1], depth+1) tb.index[pos+i] = child } } tb.nodes++ return int32(pos) } func (tb *Builder) Serialize(w io.Writer) error { var buf [binary.MaxVarintLen32]byte if err := binary.Write(w, binary.LittleEndian, tb.index[0]); err != nil { return err } var last int32 var written int for _, x := range tb.index[1:] { 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("compressed octree index in bytes: %d (%d)\n", written, 4*len(tb.index)) return nil } func (tb *Builder) WriteTo(w io.Writer) error { out := snappy.NewBufferedWriter(w) if err := tb.t.Serialize(out); err != nil { return err } if err := tb.Serialize(out); err != nil { return err } return out.Flush() } func (tb *Builder) Bytes() ([]byte, error) { var buf bytes.Buffer if err := tb.WriteTo(&buf); err != nil { return nil, err } return buf.Bytes(), nil } func (tb *Builder) Tree() *Tree { return &Tree{ EPSG: tb.t.EPSG, vertices: tb.t.Vertices, triangles: tb.t.Triangles, index: tb.index, Min: tb.t.Min, Max: tb.t.Max, } }