Clip by camera frustum

// Clip by camera frustum
vector P_ndc = toNDC(chs("path_to_camera"), @P);
float over = chf("overscan");
if(max(P_ndc.x, P_ndc.y)>(1+over) || min(P_ndc.x, P_ndc.y)<(0-over)) removepoint(geoself(), @ptnum);

// Instance attribute for RedShift
f@pscale *=0.01;
int num = chi("num");
if(num>0)
{
   int c = @ptnum%num;
   string path = concat("obj", itoa(c+1));
   s@instance = chs(path);
}