From 49175fb533db030ca3d3dee8434ea3aa905b4172 Mon Sep 17 00:00:00 2001
From: core <core@coredoes.dev>
Date: Sun, 19 Apr 2026 18:50:40 -0400
Subject: [PATCH] feat: orbits

---
 crates/unified/assets/config/planets.pc.toml | 23 +++---
 crates/unified/src/client_plugins.rs         |  1 +
 crates/unified/src/config/planet.rs          | 26 ++++++-
 crates/unified/src/config/world.rs           |  2 +-
 crates/unified/src/server/mod.rs             |  3 +
 crates/unified/src/server/orbit/mod.rs       | 74 ++++++++++++++++++++
 crates/unified/src/server/planets.rs         | 59 ++++++++++++----
 crates/unified/src/shared_plugins.rs         |  4 +-
 crates/unified/src/world_config.rs           |  1 +
 9 files changed, 168 insertions(+), 25 deletions(-)
 create mode 100644 crates/unified/src/server/orbit/mod.rs

diff --git a/crates/unified/assets/config/planets.pc.toml b/crates/unified/assets/config/planets.pc.toml
index 217a961f8c63a1f4974156de48f74829272a418e..e730ade69317f3ff293e292b36a761a2589b2e37 100644
--- a/crates/unified/assets/config/planets.pc.toml
+++ b/crates/unified/assets/config/planets.pc.toml
@@ -1,3 +1,6 @@
+[orbit]
+planet_spring_compliance = 0
+
 [[planets]]
 name = "Sun"
 sprite = "textures/sun.png"
@@ -14,7 +17,7 @@ radius = 666.66 # m
 mass = 205_000_000.0 # kg
 default_transform = [116_129.4, 0.0, 0.0]
 planet_resource = { name = "Composite", color = { LinearRgba = { red = 0.7, green = 0.7, blue = 0.7, alpha = 1.0 } }, mining_speed = 5.0 }
-orbit = { orbiting = "Sun", eccentricity = 0.2056 }
+orbit = { orbiting = "Sun", eccentricity = 0.2056, period = 299.0 }
 
 [[planets]]
 name = "Venus"
@@ -23,7 +26,7 @@ radius = 1899.8 # m
 mass = 806_166_000.0 # kg
 default_transform = [216_999.6, 0.0, 0.0]
 planet_resource = { name = "Sulfur", color = { LinearRgba = { red = 0.7, green = 0.7, blue = 0.7, alpha = 1.0 } }, mining_speed = 5.0 }
-orbit = { orbiting = "Sun", eccentricity = 0.0068 }
+orbit = { orbiting = "Sun", eccentricity = 0.0068, period = 546.0 }
 
 [[planets]]
 name = "Earth"
@@ -33,7 +36,7 @@ radius = 2000.0 # m
 mass = 16_900_000_000.0 # kg
 planet_resource = { name = "Carbon", color = { LinearRgba = { red = 1.0, green = 0.7, blue = 0.7, alpha = 1.0 } }, mining_speed = 2.0 }
 default_transform = [300_000.0, 0.0, 0.0]
-orbit = { orbiting = "Sun", eccentricity = 0.0167 }
+orbit = { orbiting = "Sun", eccentricity = 0.0167, period = 900.0 }
 
 [[planets]]
 name = "Moon"
@@ -43,7 +46,7 @@ radius = 545.4 # m
 mass = 360_236_000.0 # kg
 default_transform = [312_700.0, 0.0, 0.0]
 planet_resource = { name = "Silicon", color = { LinearRgba = { red = 0.7, green = 0.7, blue = 0.7, alpha = 1.0 } }, mining_speed = 5.0 }
-orbit = { orbiting = "Earth", eccentricity = 0.0549 }
+orbit = { orbiting = "Earth", eccentricity = 0.0549, period = 256.0 }
 
 [[planets]]
 name = "Mars"
@@ -53,7 +56,7 @@ radius = 1062.0 # m
 mass = 525_857_000.0 # kg
 default_transform = [430_000.0, 0.0, 0.0]
 planet_resource = { name = "Iron", color = { LinearRgba = { red = 0.7, green = 0.7, blue = 0.7, alpha = 1.0 } }, mining_speed = 5.0 }
-orbit = { orbiting = "Sun", eccentricity = 0.0934 }
+orbit = { orbiting = "Sun", eccentricity = 0.0934, period = 1745.0 }
 
 [[planets]]
 name = "Jupiter"
@@ -62,7 +65,7 @@ radius = 21946.0 # m
 mass = 1_131_221_218_000.0 # kg
 default_transform = [1_561_140.0, 0.0, 0.0]
 planet_resource = { name = "Hydrogen", color = { LinearRgba = { red = 0.7, green = 0.7, blue = 0.7, alpha = 1.0 } }, mining_speed = 5.0 }
-orbit = { orbiting = "Sun", eccentricity = 0.0484 }
+orbit = { orbiting = "Sun", eccentricity = 0.0484, period = 11218.0 }
 
 [[planets]]
 name = "Saturn"
@@ -71,7 +74,7 @@ radius = 18_280.4 # m
 mass = 561_386_112_000.0 # kg
 default_transform = [2_874_780.0, 0.0, 0.0]
 planet_resource = { name = "Helium", color = { LinearRgba = { red = 0.7, green = 0.7, blue = 0.7, alpha = 1.0 } }, mining_speed = 5.0 }
-orbit = { orbiting = "Sun", eccentricity = 0.0541 }
+orbit = { orbiting = "Sun", eccentricity = 0.0541, period = 28297.0 }
 
 [[planets]]
 name = "Uranus"
@@ -80,7 +83,7 @@ radius = 8014.0 # m
 mass = 69_763_532_000.0 # kg
 default_transform = [4_050_000.0, 0.0, 0.0]
 planet_resource = { name = "Rubber", color = { LinearRgba = { red = 0.7, green = 0.7, blue = 0.7, alpha = 1.0 } }, mining_speed = 5.0 }
-orbit = { orbiting = "Sun", eccentricity = 0.0472 }
+orbit = { orbiting = "Sun", eccentricity = 0.0472, period = 46791.0 }
 
 [[planets]]
 name = "Neptune"
@@ -89,7 +92,7 @@ radius = 7_766.0 # m
 mass = 106_674_649_000.0 # kg
 default_transform = [5_000_000.0, 0.0, 0.0]
 planet_resource = { name = "Methane", color = { LinearRgba = { red = 0.7, green = 0.7, blue = 0.7, alpha = 1.0 } }, mining_speed = 5.0 }
-orbit = { orbiting = "Sun", eccentricity = 0.0086 }
+orbit = { orbiting = "Sun", eccentricity = 0.0086, period = 60454.0 }
 
 [[planets]]
 name = "Pluto"
@@ -98,4 +101,4 @@ radius = 373.6 # m
 mass = 10_817_000.0 # kg
 default_transform = [5_922_300.0, 0.0, 0.0]
 planet_resource = { name = "Ice", color = { LinearRgba = { red = 0.7, green = 0.7, blue = 0.7, alpha = 1.0 } }, mining_speed = 5.0 }
-orbit = { orbiting = "Sun", eccentricity = 0.2488 }
+orbit = { orbiting = "Sun", eccentricity = 0.2488, period = 118234.0 }
diff --git a/crates/unified/src/client_plugins.rs b/crates/unified/src/client_plugins.rs
index 74e7cadbb9b07e70e54cf02392603ce83a2e6783..235e3d72d31817e441ba3be2a88f78a020680601 100644
--- a/crates/unified/src/client_plugins.rs
+++ b/crates/unified/src/client_plugins.rs
@@ -25,6 +25,7 @@ impl PluginGroup for ClientPluginGroup {
             .add(UiPlugin)
             .add(InputDispatchPlugin)
             .add(InputManagerPlugin::<crate::client::input::ClientAction>::default())
+            .add(PhysicsDebugPlugin)
     }
 }
 
diff --git a/crates/unified/src/config/planet.rs b/crates/unified/src/config/planet.rs
index f617f38cf038137a546e62055592cd3669683556..c95a67c0c7f85fd90dacea6a0735fe13dfb90612 100644
--- a/crates/unified/src/config/planet.rs
+++ b/crates/unified/src/config/planet.rs
@@ -6,7 +6,7 @@ use serde::{Deserialize, Serialize};
 
 #[derive(Deserialize, Asset, TypePath, Component, Serialize, Clone, Debug)]
 #[require(
-    RigidBody::Static,
+    RigidBody::Dynamic,
     Replicated,
 )]
 pub struct Planet {
@@ -21,6 +21,23 @@ pub struct Planet {
     pub orbit: Option<OrbitData>
 }
 
+#[derive(Component, Serialize, Deserialize)]
+#[require(
+    RigidBody::Static,
+    Replicated,
+)]
+pub struct PlanetSpring {
+    pub name: String
+}
+
+#[derive(Component, Serialize, Deserialize)]
+#[require(
+    Replicated,
+)]
+pub struct PlanetSpringJoint {
+    pub name: String
+}
+
 #[derive(Deserialize, TypePath, Serialize, Clone, Debug)]
 pub struct PlanetResource {
     pub name: String,
@@ -32,6 +49,7 @@ pub struct PlanetResource {
 pub struct OrbitData {
     pub orbiting: String,
     pub eccentricity: f32,
+    pub period: f32
 }
 
 #[derive(Deserialize, TypePath, Serialize, Clone, Debug)]
@@ -50,4 +68,10 @@ pub struct PlanetBundle {
 #[derive(Deserialize, Asset, TypePath)]
 pub struct PlanetConfigCollection {
     pub planets: Vec<Planet>,
+    pub orbit: OrbitConfig
+}
+
+#[derive(Deserialize, Asset, TypePath, Clone, Debug)]
+pub struct OrbitConfig {
+    pub planet_spring_compliance: f32
 }
diff --git a/crates/unified/src/config/world.rs b/crates/unified/src/config/world.rs
index e890089832df793d47639d443c18e4f5865f9ba5..45cbb02f2ee82b790ebc9143b02610b8d0c045e6 100644
--- a/crates/unified/src/config/world.rs
+++ b/crates/unified/src/config/world.rs
@@ -6,7 +6,7 @@ use serde::Deserialize;
 pub struct GlobalWorldConfig {
     pub world: WorldConfig,
     pub part: WPartConfig,
-    pub hearty: HeartyConfig,
+    pub hearty: HeartyConfig
 }
 
 #[derive(Deserialize, Asset, TypePath, Clone)]
diff --git a/crates/unified/src/server/mod.rs b/crates/unified/src/server/mod.rs
index d5a2ebdea4e4ce88913981407eb2d1383df957ab..d5f8de9b3e7fbc199400513fadf0b380b872e420 100644
--- a/crates/unified/src/server/mod.rs
+++ b/crates/unified/src/server/mod.rs
@@ -8,6 +8,7 @@ mod damping;
 pub mod planets;
 pub mod player;
 mod system_sets;
+pub mod orbit;
 
 use crate::server::craft::craft_plugin;
 use crate::server::damping::damping_plugin;
@@ -29,6 +30,7 @@ use aeronet_websocket::server::WebSocketServer;
 use crate::prelude::*;
 use bevy_replicon::prelude::Replicated;
 use std::net::SocketAddr;
+use crate::server::orbit::OrbitPlugin;
 use crate::server::player::thrust::server_thrust_plugin;
 
 pub struct ServerPlugin {
@@ -63,6 +65,7 @@ impl Plugin for ServerPlugin {
         .add_plugins(heat_conduction_plugin)*/
         .add_plugins(drill_plugin)
         .add_plugins(craft_plugin)
+        .add_plugins(OrbitPlugin)
         .add_plugins(damping_plugin)
         .configure_sets(Update, WorldUpdateSet.before(PlayerInputSet));
         //.configure_sets(Update, PlayerInputSet.before(PhysicsSet::SyncBackend));
diff --git a/crates/unified/src/server/orbit/mod.rs b/crates/unified/src/server/orbit/mod.rs
new file mode 100644
index 0000000000000000000000000000000000000000..e8b4c0c89b64a57f06f2512def7a5e4f9c5ec16b
--- /dev/null
+++ b/crates/unified/src/server/orbit/mod.rs
@@ -0,0 +1,74 @@
+use std::collections::HashMap;
+use avian2d::math::TAU;
+use avian2d::prelude::LinearVelocity;
+use bevy::log::debug;
+use bevy::math::ops::atan2;
+use bevy::prelude::{Component, Plugin, Transform};
+use bevy::time::Time;
+use serde::{Deserialize, Serialize};
+use crate::config::planet::{Planet, PlanetSpring, PlanetSpringJoint};
+use crate::prelude::{App, Query, Res, Update, Without};
+
+pub struct OrbitPlugin;
+impl Plugin for OrbitPlugin {
+    fn build(&self, app: &mut App) {
+        app.add_systems(Update, update_orbits);
+    }
+}
+
+fn update_orbits(
+    mut planets: Query<(&Planet, &Transform, &mut LinearVelocity), Without<PlanetSpring>>,
+    planets_2: Query<(&Planet, &Transform), Without<PlanetSpring>>,
+    mut planet_springs: Query<(&PlanetSpring, &mut Transform), Without<Planet>>,
+    time: Res<Time>
+) {
+    let parent_velocities = planets.iter().map(|u| (u.0.name.clone(), u.2.clone())).collect::<HashMap<String, LinearVelocity>>();
+    for (planet, _, mut vel) in planets.iter_mut() {
+        let Some(orbit_data) = &planet.orbit else { continue; };
+        // find parent
+        let Some(parent) = planets_2.iter().find(|u| u.0.name == orbit_data.orbiting) else { continue; };
+
+        let a = (planet.default_transform[0] - parent.0.default_transform[0]) / (1.0 - orbit_data.eccentricity);
+        let e = orbit_data.eccentricity;
+        let t = orbit_data.period;
+
+        let time = time.elapsed_secs();
+
+        // calculate position of the planet
+        let m = (TAU / t) * time;
+        let e_k = iterative_kepler(m, e);
+        let nu = 2.0 * atan2(
+            (1.0 + e).sqrt() * (e_k / 2.0).sin(),
+            (1.0 - e).sqrt() * (e_k / 2.0).cos(),
+        );
+        let r = a * (1.0 - e * e_k.cos());
+
+        let x = r * nu.cos();
+        let y = r * nu.sin();
+
+        // find the spring
+        let Some(mut planet_spring) = planet_springs.iter_mut().find(|u| u.0.name == planet.name) else { continue; };
+        planet_spring.1.translation.x = x + parent.1.translation.x;
+        planet_spring.1.translation.y = y + parent.1.translation.y;
+
+        let Some(parent_velocity) = parent_velocities.get(&orbit_data.orbiting) else { continue; };
+        let de_dt = (TAU / t) / (1.0 - e * e_k.cos());
+        let b_factor = (1.0 - e * e).sqrt();
+        let vx = -a * e_k.sin() * de_dt;
+        let vy = a * b_factor * e_k.cos() * de_dt;
+        vel.x = vx + parent_velocity.x;
+        vel.y = vy + parent_velocity.y;
+    }
+}
+
+fn iterative_kepler(m: f32, e: f32) -> f32 {
+    let mut output = m;
+    for _ in 0..100 {
+        let d = (m - output + e * output.sin()) / (1.0 - e * output.cos());
+        output += d;
+        if d.abs() < 1e-10 {
+            break;
+        }
+    }
+    output
+}
\ No newline at end of file
diff --git a/crates/unified/src/server/planets.rs b/crates/unified/src/server/planets.rs
index e510adc603e8c04080da1b1a47ffe92ecc915f02..45f92cdca116b4198b71c01979e24982cbd96453 100644
--- a/crates/unified/src/server/planets.rs
+++ b/crates/unified/src/server/planets.rs
@@ -2,6 +2,7 @@ use crate::{config::planet::{Planet, PlanetBundle, PlanetConfigCollection}, ecs:
 use bevy::asset::Handle;
 use crate::prelude::*;
 use bevy_replicon::prelude::Replicated;
+use crate::config::planet::{PlanetSpring, PlanetSpringJoint};
 
 pub fn planets_plugin(app: &mut App) {
     app.init_resource::<PlanetConfigResource>()
@@ -29,6 +30,7 @@ pub fn update_planets(
         &mut Transform,
         &mut Mass,
     )>,
+    mut planet_joint_springs: Query<(&PlanetSpringJoint, &mut FixedJoint)>
 ) {
     let Some(handle) = planets.handle.as_ref() else {
         return;
@@ -43,7 +45,7 @@ pub fn update_planets(
                     debug!("planet config loaded - creating planets");
                     let planet_config = assets.get(*id).unwrap();
                     for planet in &planet_config.planets {
-                        commands
+                        let mut planet_entity = commands
                             .spawn(PlanetBundle {
                                 planet: planet.clone(),
                                 transform: Transform::from_xyz(
@@ -53,14 +55,31 @@ pub fn update_planets(
                                 ),
                                 collider: Collider::circle(planet.radius),
                                 mass: Mass(planet.mass)
-                            })
-                            .insert(Replicated)
-                            .with_child((
+                            }).with_child((
                                 Collider::circle(planet.radius+2.0),
                                 Sensor,
                                 PlanetSensor(planet.name.clone()),
                                 CollisionEventsEnabled,
+                            )).id();
+                        if planet.orbit.is_some() {
+                            let spring =commands.spawn((
+                                PlanetSpring {
+                                    name: planet.name.clone()
+                                },
+                                Transform::from_xyz(
+                                    planet.default_transform[0],
+                                    planet.default_transform[1],
+                                    planet.default_transform[2],
+                                )
+                            )).id();
+                            commands.spawn((
+                                PlanetSpringJoint {
+                                    name: planet.name.clone()
+                                },
+                                FixedJoint::new(planet_entity, spring).with_point_compliance(planet_config.orbit.planet_spring_compliance)
                             ));
+                        }
+
                         trace!(?planet, "new planet spawned");
                     }
                 }
@@ -70,6 +89,9 @@ pub fn update_planets(
                     trace!("planet config modified - reloading planets");
                     let planet_config = assets.get(*id).unwrap();
 
+                    info!("updating compliance on all planet spring joints");
+                    planet_joint_springs.iter_mut().for_each(|mut u| u.1.point_compliance = planet_config.orbit.planet_spring_compliance);
+
                     for planet in &planet_config.planets {
                         let existing_planet = q_planets
                             .iter_mut()
@@ -83,15 +105,10 @@ pub fn update_planets(
                                 .remove::<Collider>()
                                 .insert(Collider::circle(planet.radius));
                             *e_planet = planet.clone();
-                            e_transform.translation = Vec3::new(
-                                planet.default_transform[0],
-                                planet.default_transform[1],
-                                planet.default_transform[2],
-                            );
                             *e_mass = Mass(planet.mass);
                             trace!(?planet, "planet hot-reloaded");
                         } else {
-                            commands
+                            let planet_entity = commands
                                 .spawn(PlanetBundle {
                                     planet: planet.clone(),
                                     transform: Transform::from_xyz(
@@ -103,8 +120,26 @@ pub fn update_planets(
                                     mass: Mass(
                                         planet.mass,
                                     ),
-                                })
-                                .insert(Replicated);
+                                }).id();
+
+                            if planet.orbit.is_some() {
+                                let spring =commands.spawn((
+                                    PlanetSpring {
+                                        name: planet.name.clone()
+                                    },
+                                    Transform::from_xyz(
+                                        planet.default_transform[0],
+                                        planet.default_transform[1],
+                                        planet.default_transform[2],
+                                    )
+                                )).id();
+                                commands.spawn((
+                                    PlanetSpringJoint {
+                                        name: planet.name.clone()
+                                    },
+                                    FixedJoint::new(planet_entity, spring).with_point_compliance(planet_config.orbit.planet_spring_compliance)
+                                ));
+                            }
                             trace!(?planet, "new planet spawned");
                         }
                     }
diff --git a/crates/unified/src/shared_plugins.rs b/crates/unified/src/shared_plugins.rs
index e536a9aeb63a87d8fa9bfbbaecc037051067a697..2caa9c77d1716ab9f15d4f5afa2b0058d480df06 100644
--- a/crates/unified/src/shared_plugins.rs
+++ b/crates/unified/src/shared_plugins.rs
@@ -1,5 +1,5 @@
 use crate::attachment::{Joint, JointOf, PartInShip, Peer, Ship, SnapOf, SnapOfJoint};
-use crate::config::planet::{Planet, PlanetConfigCollection};
+use crate::config::planet::{Planet, PlanetConfigCollection, PlanetSpring, PlanetSpringJoint};
 use crate::config::recipe::RecipesConfig;
 use crate::ecs::{CanCraft, CraftPartRequest, DragRequestEvent, Drill, Hi, Part, Particles, Player, PlayerStorage, SingleStorage, Temperature, ToggleDrillEvent};
 use bevy::app::{App, PluginGroup, PluginGroupBuilder};
@@ -60,6 +60,8 @@ pub fn register_everything(app: &mut App) {
     app.replicate::<Temperature>();
     app.replicate::<Drill>();
     app.replicate::<SingleStorage>();
+    app.replicate::<PlanetSpring>();
+    app.replicate::<PlanetSpringJoint>();
 }
 
 fn physics_setup_plugin(app: &mut App) {
diff --git a/crates/unified/src/world_config.rs b/crates/unified/src/world_config.rs
index 721e5dbb314f4ade3885d9e457a1841ab893da67..6ab4d3e21a22bdd9c5c5153f98b6e410bfcbf3a0 100644
--- a/crates/unified/src/world_config.rs
+++ b/crates/unified/src/world_config.rs
@@ -1,5 +1,6 @@
 use crate::config::world::GlobalWorldConfig;
 use bevy::asset::Handle;
+use crate::config::planet::PlanetSpringJoint;
 use crate::prelude::*;
 
 pub fn world_config_plugin(app: &mut App) {