use std::iter;
use na::Point3;
pub fn remove_unused_points<V>(points: &mut Vec<V>, idx: &mut [Point3<u32>]) {
let mut used: Vec<bool> = iter::repeat(false).take(points.len()).collect();
let mut remap: Vec<usize> = (0..points.len()).map(|i| i).collect();
let used = &mut used[..];
let remap = &mut remap[..];
for i in idx.iter() {
used[i.x as usize] = true;
used[i.y as usize] = true;
used[i.z as usize] = true;
}
let mut i = 0;
while i != points.len() {
if !used[i] {
let _ = points.swap_remove(i);
remap[points.len()] = i;
used[i] = used[points.len()];
} else {
i = i + 1;
}
}
for id in idx.iter_mut() {
id.x = remap[id.x as usize] as u32;
id.y = remap[id.y as usize] as u32;
id.z = remap[id.z as usize] as u32;
}
}