vector $p = particle.position;

vector $t = camera.translate;

vector $r = camera.rotate;
$p = rot(rot(rot($p,«-1,0,0»,deg_to_rad($r.z),),«0,-1,0»,deg_to_rad($r.y)),«0,0,-1»,deg_to_rad($r.x))-$t;
$p = $p/$p.z*cameraShape.focalLength;
$p.x = $p.x/cameraShape.horizontalFilmAperture/25.4+0.5;
$p.y = $p.y/cameraShape.verticalFilmAperture/25.4+0.5;