Refactor two body state vector representations

crates/lox-space/examples/iss.rs

@@ -14,12 +14,9 @@ fn main() {
     let epoch = Epoch::from_date_and_time(TimeScale::TDB, date, time);
     let position = DVec3::new(6068279.27, -1692843.94, -2516619.18) * 1e-3;
     let velocity = DVec3::new(-660.415582, 5495.938726, -5303.093233) * 1e-3;
-    let iss = Cartesian::new(epoch, Earth, position, velocity);
+    let iss = Cartesian::new(epoch, Earth, Icrf, position, velocity);
 
-    println!(
-        "ISS Orbit for Julian Day {}",
-        iss.epoch().days_since_j2000(),
-    );
+    println!("ISS Orbit for Julian Day {}", iss.time().days_since_j2000(),);
     println!("=============================");
     println!("Semi-major axis: {:.3} km", iss.semi_major());
     println!("Eccentricity: {:.6}", iss.eccentricity());

crates/lox-space/src/prelude.rs

@@ -7,8 +7,7 @@
  */
 
 pub use lox_core::bodies::*;
-
+pub use lox_core::frames::*;
 pub use lox_core::time::dates::*;
 pub use lox_core::time::epochs::*;
-
 pub use lox_core::two_body::{Cartesian, DVec3, Keplerian, TwoBody};

crates/lox_core/src/bodies.rs

@@ -92,6 +92,28 @@ macro_rules! body {
             }
         }
 
+        impl Display for $i {
+            fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
+                write!(f, "{}", self.name())
+            }
+        }
+    };
+    ($i:ident, $t:ident, $name:literal, $naif_id:literal) => {
+        #[derive(Clone, Copy, Debug, Eq, PartialEq)]
+        pub struct $i;
+
+        impl $t for $i {}
+
+        impl Body for $i {
+            fn id(&self) -> NaifId {
+                NaifId($naif_id)
+            }
+
+            fn name(&self) -> &'static str {
+                $name
+            }
+        }
+
         impl Display for $i {
             fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
                 write!(f, "{}", self.name())
@@ -118,16 +140,19 @@ body! { Neptune, Planet, 899 }
 body! { Pluto, Planet, 999 }
 
 // Barycenters.
-body! { SolarSystemBarycenter, "Solar System Barycenter", 0 }
-body! { MercuryBarycenter, "Mercury Barycenter", 1 }
-body! { VenusBarycenter, "Venus Barycenter", 2 }
-body! { EarthBarycenter, "Earth Barycenter", 3 }
-body! { MarsBarycenter, "Mars Barycenter", 4 }
-body! { JupiterBarycenter, "Jupiter Barycenter", 5 }
-body! { SaturnBarycenter, "Saturn Barycenter", 6 }
-body! { UranusBarycenter, "Uranus Barycenter", 7 }
-body! { NeptuneBarycenter, "Neptune Barycenter", 8 }
-body! { PlutoBarycenter, "Pluto Barycenter", 9 }
+pub trait Barycenter: PointMass + DynClone {}
+clone_trait_object!(Barycenter);
+
+body! { SolarSystemBarycenter, Barycenter, "Solar System Barycenter", 0 }
+body! { MercuryBarycenter, Barycenter, "Mercury Barycenter", 1 }
+body! { VenusBarycenter, Barycenter, "Venus Barycenter", 2 }
+body! { EarthBarycenter, Barycenter, "Earth Barycenter", 3 }
+body! { MarsBarycenter, Barycenter, "Mars Barycenter", 4 }
+body! { JupiterBarycenter, Barycenter, "Jupiter Barycenter", 5 }
+body! { SaturnBarycenter, Barycenter, "Saturn Barycenter", 6 }
+body! { UranusBarycenter, Barycenter, "Uranus Barycenter", 7 }
+body! { NeptuneBarycenter, Barycenter, "Neptune Barycenter", 8 }
+body! { PlutoBarycenter, Barycenter, "Pluto Barycenter", 9 }
 
 impl PointMass for SolarSystemBarycenter {
     fn gravitational_parameter(&self) -> f64 {
@@ -545,12 +570,10 @@ pub trait TriAxial: Ellipsoid {
     fn along_orbit_radius(&self) -> f64;
 }
 
-pub trait PointMass: Body + DynClone {
+pub trait PointMass: Body {
     fn gravitational_parameter(&self) -> f64;
 }
 
-clone_trait_object!(PointMass);
-
 pub type PolynomialCoefficients = (f64, f64, f64, &'static [f64]);
 
 pub type NutationPrecessionCoefficients = (&'static [f64], &'static [f64]);

crates/lox_core/src/frames.rs

@@ -15,11 +15,25 @@ pub mod iau;
 // TODO: Replace with proper `Epoch` type
 type Epoch = f64;
 
-pub trait ReferenceFrame {
-    fn is_inertial(&self) -> bool;
+pub trait ReferenceFrame {}
+
+pub trait InertialFrame: ReferenceFrame {
+    fn is_inertial(&self) -> bool {
+        true
+    }
+
+    fn is_rotating(&self) -> bool {
+        false
+    }
+}
+
+pub trait RotatingFrame: ReferenceFrame {
+    fn is_inertial(&self) -> bool {
+        false
+    }
 
     fn is_rotating(&self) -> bool {
-        !self.is_inertial()
+        true
     }
 }
 
@@ -32,11 +46,8 @@ impl Display for Icrf {
     }
 }
 
-impl ReferenceFrame for Icrf {
-    fn is_inertial(&self) -> bool {
-        true
-    }
-}
+impl ReferenceFrame for Icrf {}
+impl InertialFrame for Icrf {}
 
 pub fn rotation_matrix_derivative(m: DMat3, v: DVec3) -> DMat3 {
     let sx = DVec3::new(0.0, v.z, v.y);

crates/lox_core/src/frames/iau.rs

@@ -6,22 +6,25 @@
  * file, you can obtain one at https://mozilla.org/MPL/2.0/.
  */
 
-use std::fmt::Debug;
+use std::fmt::{Debug, Display, Formatter};
 
 use glam::{DMat3, DVec3};
 
 use crate::bodies::RotationalElements;
-use crate::frames::{Epoch, FromFrame, Icrf, ReferenceFrame, Rotation};
+use crate::frames::{Epoch, FromFrame, Icrf, ReferenceFrame, RotatingFrame, Rotation};
 
 #[derive(Debug, Copy, Clone)]
 pub struct BodyFixed<T: RotationalElements>(pub T);
 
-impl<T: RotationalElements> ReferenceFrame for BodyFixed<T> {
-    fn is_inertial(&self) -> bool {
-        false
+impl<T: RotationalElements> Display for BodyFixed<T> {
+    fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
+        write!(f, "IAU_{}", &self.0.name().to_uppercase())
     }
 }
 
+impl<T: RotationalElements> ReferenceFrame for BodyFixed<T> {}
+impl<T: RotationalElements> RotatingFrame for BodyFixed<T> {}
+
 impl<T: RotationalElements> FromFrame<Icrf> for BodyFixed<T> {
     fn rotation_from(&self, _: Icrf, t: Epoch) -> Rotation {
         let (right_ascension, declination, prime_meridian) = T::rotational_elements(t);
@@ -49,6 +52,7 @@ mod tests {
     #[test]
     fn test_bodyfixed() {
         let iau_jupiter = BodyFixed(Jupiter);
+        assert_eq!(format!("{}", iau_jupiter), "IAU_JUPITER");
         assert!(!iau_jupiter.is_inertial());
         assert!(iau_jupiter.is_rotating());