From 63bd19127f66dda81007fcd0d8857e978740101f Mon Sep 17 00:00:00 2001
From: Jon Santmyer <jon@jonsantmyer.com>
Date: Mon, 30 Sep 2024 12:01:07 -0400
Subject: First commit

---
 src/orbital.rs | 164 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 164 insertions(+)
 create mode 100644 src/orbital.rs

(limited to 'src/orbital.rs')

diff --git a/src/orbital.rs b/src/orbital.rs
new file mode 100644
index 0000000..178273a
--- /dev/null
+++ b/src/orbital.rs
@@ -0,0 +1,164 @@
+use super::units::*;
+use super::system::System;
+use std::vec::Vec;
+use std::rc::Rc;
+use std::cell::RefCell;
+
+pub struct Orbital
+{
+    origin : Option<usize>,
+    
+    //Euler angles for a given time (T) relative to origin
+    rel_pos : Option<(Second, Meter, Rad, Rad, Rad)>,
+    //Position for a given time (T) in absolute system coordinates
+    abs_pos : Option<(Second, Meter, Meter, Meter)>,
+
+    name : String,
+
+    //Physical parameters
+    mass : Kilogram,
+    radius : Meter,
+
+    //Orbital parameters
+    semi_major_axis : Meter,
+    eccentricity : f64,
+    inclination : Rad,
+    longitude_asc_node : Rad,
+    argument_periapsis : Rad,
+    mean_anomaly_epoch : Rad,
+}
+
+pub struct OrbitalBuilder
+{
+    origin : Option<usize>,
+    name : String,
+    mass : Kilogram,
+    radius : Meter,
+    semi_major_axis : Meter,
+    eccentricity : f64,
+    inclination : Rad,
+    longitude_asc_node : Rad,
+    argument_periapsis : Rad,
+    mean_anomaly_epoch : Rad,
+}
+
+impl Orbital
+{
+    pub fn tick(&mut self,
+               origin : &mut Orbital,
+               t : Second)
+    {
+        match self.rel_pos {
+            None => {},
+            Some(rel_pos) => {
+                if rel_pos.0 == t { return; }
+            }
+        }
+
+        let origin_mass = origin.mass;
+
+        let std_grav_param = GRAVITATIONAL_CONSTANT * (origin_mass + self.mass);
+        let mean_angular_motion = f64::sqrt(std_grav_param / self.semi_major_axis.powi(3));
+        let mean_anomaly = self.mean_anomaly_epoch + (mean_angular_motion * t as f64);
+
+        let mut eccentric_anomaly = mean_anomaly;
+        loop {
+            let de = (eccentric_anomaly - 
+                      self.eccentricity * eccentric_anomaly.sin() -
+                      mean_anomaly) /
+                (1.0 - self.eccentricity * eccentric_anomaly.cos());
+            eccentric_anomaly -= de;
+            if de.abs() < 1e6 { break; }
+        }
+
+        //True anomaly
+        let beta = self.eccentricity /
+            (1.0 + f64::sqrt(1.0 - self.eccentricity.powi(2)));
+        let true_anomaly = eccentric_anomaly * 2.0 * 
+            f64::atan((beta * eccentric_anomaly.sin()) /
+                      (1.0 - beta * eccentric_anomaly.cos()));
+
+        let distance = self.semi_major_axis * 
+            (1.0 - self.eccentricity * eccentric_anomaly.cos());
+
+        self.rel_pos = Some((t, distance, self.longitude_asc_node, self.inclination, true_anomaly));
+        println!("{0:?}", self.rel_pos.unwrap());
+    }
+
+    pub fn pos(&mut self,
+               system : &System,
+               t : Second)
+    -> (Meter, Meter, Meter)
+    {
+        (0.0, 0.0, 0.0)
+    }
+
+    pub fn name(&self) -> &String { &self.name }
+
+    pub fn origin(&self) -> Option<usize> { self.origin }
+}
+
+impl OrbitalBuilder
+{
+    pub fn new() -> OrbitalBuilder {
+        OrbitalBuilder {
+            origin : None,
+            name : "".to_string(),
+            mass : 0.0,
+            radius : 0.0,
+            semi_major_axis : 0.0,
+            eccentricity : 0.0,
+            inclination : 0.0,
+            longitude_asc_node : 0.0,
+            argument_periapsis : 0.0,
+            mean_anomaly_epoch : 0.0,
+        }
+    }
+    pub fn orbits(mut self, parent : usize) -> OrbitalBuilder
+    { self.origin = Some(parent); self }
+
+    pub fn name(mut self, name : String) -> OrbitalBuilder
+    { self.name = name; self }
+
+    pub fn mass(mut self, mass : Kilogram) -> OrbitalBuilder
+    { self.mass = mass; self }
+
+    pub fn radius(mut self, radius : Meter) -> OrbitalBuilder
+    { self.radius = radius; self }
+
+    pub fn semi_major_axis(mut self, sma : Meter) -> OrbitalBuilder
+    { self.semi_major_axis = sma; self }
+
+    pub fn eccentricity(mut self, e : Rad) -> OrbitalBuilder
+    { self.eccentricity = e; self }
+
+    pub fn inclination(mut self, i : Rad) -> OrbitalBuilder
+    { self.inclination = i; self }
+
+    pub fn long_asc_node(mut self, omega : Rad) -> OrbitalBuilder
+    { self.longitude_asc_node = omega; self }
+
+    pub fn argument_periapsis(mut self, w : Rad) -> OrbitalBuilder
+    { self.argument_periapsis = w; self }
+
+    pub fn mean_anomaly_epoch(mut self, mean_anomaly : Rad) -> OrbitalBuilder
+    { self.mean_anomaly_epoch = mean_anomaly; self }
+
+    pub fn build(self) -> Orbital
+    {
+        Orbital {
+            origin : self.origin,
+            rel_pos : None,
+            abs_pos : None,
+            name : self.name,
+            mass : self.mass,
+            radius : self.radius,
+            semi_major_axis : self.semi_major_axis,
+            eccentricity : self.eccentricity,
+            inclination : self.inclination,
+            longitude_asc_node : self.longitude_asc_node,
+            argument_periapsis : self.argument_periapsis,
+            mean_anomaly_epoch : self.mean_anomaly_epoch
+        }
+    }
+}
-- 
cgit v1.2.1