func NumSharpTurns(points [][2]float64) int {
arrLens := len(points) - 2
// dists := make([]float64, arrLens)
angles := make([]float64, arrLens)
for idx := 0; idx < arrLens; idx++ {
var p1, p2, p3, v1, v2 mgl64.Vec2
p1 = points[idx]
p2 = points[idx+1]
p3 = points[idx+2]
v1 = p2.Sub(p1)
v2 = p3.Sub(p2)
// dists[idx] := v1.Len()
angles[idx] = AngleBetween(v1, v2) // (radians)
}
const maxAngleChange = .4 * math.Pi
const maxDistChange = 4
numSharpTurns := 0 // sharp turn is whenn the angles add up to maxAngleChange for 4 consecutive points
for idx := 0; idx < arrLens; idx++ {
dAngle := 0.0
for count := 0; count < maxDistChange && idx < arrLens; count++ {
dAngle += angles[idx]
idx++
}
if dAngle > maxAngleChange {
numSharpTurns++
}
}
return numSharpTurns
}
func (w *Widget) ParentToLocal(ParentPosition mgl64.Vec2) (LocalPosition mgl64.Vec2) {
return ParentPosition.Sub(w.pos)
}
