mirror of
https://github.com/superseriousbusiness/gotosocial.git
synced 2024-10-18 00:02:49 +02:00
98263a7de6
* start fixing up tests * fix up tests + automate with drone * fiddle with linting * messing about with drone.yml * some more fiddling * hmmm * add cache * add vendor directory * verbose * ci updates * update some little things * update sig
54 lines
1.9 KiB
Go
54 lines
1.9 KiB
Go
// Copyright 2018 Google Inc. All rights reserved.
|
|
//
|
|
// Licensed under the Apache License, Version 2.0 (the "License");
|
|
// you may not use this file except in compliance with the License.
|
|
// You may obtain a copy of the License at
|
|
//
|
|
// http://www.apache.org/licenses/LICENSE-2.0
|
|
//
|
|
// Unless required by applicable law or agreed to in writing, software
|
|
// distributed under the License is distributed on an "AS IS" BASIS,
|
|
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
|
|
// See the License for the specific language governing permissions and
|
|
// limitations under the License.
|
|
|
|
package s2
|
|
|
|
// This file defines various measures for polylines on the sphere. These are
|
|
// low-level methods that work directly with arrays of Points. They are used to
|
|
// implement the methods in various other measures files.
|
|
|
|
import (
|
|
"github.com/golang/geo/r3"
|
|
"github.com/golang/geo/s1"
|
|
)
|
|
|
|
// polylineLength returns the length of the given Polyline.
|
|
// It returns 0 for polylines with fewer than two vertices.
|
|
func polylineLength(p []Point) s1.Angle {
|
|
var length s1.Angle
|
|
|
|
for i := 1; i < len(p); i++ {
|
|
length += p[i-1].Distance(p[i])
|
|
}
|
|
return length
|
|
}
|
|
|
|
// polylineCentroid returns the true centroid of the polyline multiplied by the
|
|
// length of the polyline. The result is not unit length, so you may wish to
|
|
// normalize it.
|
|
//
|
|
// Scaling by the Polyline length makes it easy to compute the centroid
|
|
// of several Polylines (by simply adding up their centroids).
|
|
//
|
|
// Note that for degenerate Polylines (e.g., AA) this returns Point(0, 0, 0).
|
|
// (This answer is correct; the result of this function is a line integral over
|
|
// the polyline, whose value is always zero if the polyline is degenerate.)
|
|
func polylineCentroid(p []Point) Point {
|
|
var centroid r3.Vector
|
|
for i := 1; i < len(p); i++ {
|
|
centroid = centroid.Add(EdgeTrueCentroid(p[i-1], p[i]).Vector)
|
|
}
|
|
return Point{centroid}
|
|
}
|