revamp/replace pointsinside

[jefferis]

Still having problems with pointsinside.

load("/GD/LMBD/Papers/2017FAFB/bocklab_public/temca2data/geometry_analysis/data/pns.RData")
lhr=as.mesh3d(subset(FAFB13NP.surf, 'LH_R'))
pns.lh=nlapply(pns, subset, function(x) pointsinside(x, lhr))

pns.lh includes a lot of stuff outside the LH for some reason – only things that are distant though.

One option, given below would be to use a bounding box check to speed up computation as well as rejecting distant points.

# pointsinside seems to be misbehaving for points a long way away
contains_points <- function(obj, points, ...) UseMethod("contains_points")

contains_points.boundingbox <- function(obj, points,  ...) {
  xyz=xyzmatrix(points)
  xyz[,1] >= obj[1,1] & xyz[,2] >= obj[1,2] & xyz[,3] >= obj[1,3] &
    xyz[,1] <= obj[2,1] & xyz[,2] <= obj[2,2] & xyz[,3] <= obj[2,3]
}

contains_points.mesh3d <- function(obj, points,  ...) {
  xyz=xyzmatrix(points)
  inbb=contains_points(boundingbox(obj), xyz, ...)
  iosurf=pointsinside(xyz[inbb,], surf = obj, ...)
  res=inbb
  res[inbb]=iosurf
  res
}

contains_points.hxsurf<-contains_points.mesh3d

[jefferis]

Just to note that the example above pns.lh works fine after Rvcg commit: zarquon42b/Rvcg@63329d0

[jefferis]

Could also add a method for ashape3d objects:

contains_points.ashape3d<-function(obj, points,  ...) {
  alphashape3d::inashape3d(obj, points=xyzmatrix(points), ...)
}

[jefferis]

contains_points.mesh3d <- function(obj, points,  ...) {
  xyz=xyzmatrix(points)
  inbb=contains_points(boundingbox(obj), xyz, ...)
  iosurf=pointsinside(xyz[inbb,,drop=F], surf = obj, ...)
  res=inbb
  res[inbb]=iosurf
  res
}

[jefferis]

Initial work on https://github.com/jefferis/nat/tree/feature/improve-pointsinside (see ac15aa9)

[jefferis]

@fmlove this issue will be of interest

[jefferis]

Have to decided to merge to master as is (i.e. 0cc65c0). This may not be the last word, but it does seem to solve the majority of issues in the wild including the issues faced by @fmlove.

[jefferis]

closed by 3362ad8