Cull by Camera

string camera = chs("camera");
vector campos = toNDC(camera,@P);

if (campos.x<(0-ch("x_pad"))|| campos.x>1+ch("x_pad") || campos.y<0-ch("y_pad") || campos.y>1+ch("y_pad") || campos.z>0){@group_blast = 1; f@blast=1;}