MTSatellite_old/common/coverage.go
2018-12-13 21:09:02 +01:00

87 lines
1.5 KiB
Go

// Copyright 2014, 2015 by Sascha L. Teichmann
// Use of this source code is governed by the MIT license
// that can be found in the LICENSE file.
package common
import "sync"
type zRange struct {
y1 int16
y2 int16
xRange *Span
}
type Coverage3D struct {
pool *SpanPool
zRanges map[int16]*zRange
mu sync.RWMutex
}
type Range struct {
Z int16
Y1 int16
Y2 int16
X1 int16
X2 int16
}
func NewCoverage3D() *Coverage3D {
return &Coverage3D{
pool: NewSpanPool(),
zRanges: map[int16]*zRange{}}
}
func (c3d *Coverage3D) Insert(c Coord) {
c3d.mu.Lock()
defer c3d.mu.Unlock()
zr := c3d.zRanges[c.Z]
if zr == nil {
xr := c3d.pool.Alloc()
xr.From = int32(c.X)
xr.To = int32(c.X)
xr.Next = nil
c3d.zRanges[c.Z] = &zRange{
y1: c.Y,
y2: c.Y,
xRange: xr}
return
}
zr.xRange = c3d.pool.Insert(zr.xRange, int32(c.X), 0)
if c.Y < zr.y1 {
zr.y1 = c.Y
}
if c.Y > zr.y2 {
zr.y2 = c.Y
}
}
func (c3d *Coverage3D) Query(c1, c2 Coord) []Range {
c1, c2 = MinCoord(c1, c2), MaxCoord(c1, c2)
c3d.mu.RLock()
defer c3d.mu.RUnlock()
r := make([]Range, 0, 32)
for z := c1.Z; z <= c2.Z; z++ {
zr := c3d.zRanges[z]
if zr == nil || c1.Y > zr.y2 || c2.Y < zr.y1 {
continue
}
y1, y2 := max16(c1.Y, zr.y1), min16(c2.Y, zr.y2)
for xr := zr.xRange; xr != nil && xr.From <= int32(c2.X); xr = xr.Next {
if xr.To < int32(c1.X) {
continue
}
r = append(r, Range{
Z: z,
Y1: y1,
Y2: y2,
X1: max16(c1.X, int16(xr.From)),
X2: min16(c2.X, int16(xr.To))})
}
}
return r
}