Group Points by Camera Visibility

A point wrangle grouping points inside a camera's frustum with an extra check for visibility / occlusion.

string cam = chs('camera');
vector ndc = toNDC(cam, v@P);

int in_frustum = ndc[0]>=0.0 && ndc[0]<=1.0 && ndc[1]>=0.0 && ndc[1]<=1.0;

i@group_visible = 0;

if(in_frustum){
    vector pos_cam = ptransform( cam, "space:object", {0,0,0} );
    vector dir_cam = pos_cam - v@P;
    vector pos_ray = v@P + normalize(dir_cam) * 1e-3;
    int pr_hit = intersect(0, pos_ray, dir_cam, set(0), set(0));
    i@group_visible = pr_hit < 0;
}