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Version: 0.2.0

Systems

Systems are functions that run on matching sets of entities every frame (or on a schedule). Source: src/systems/.

Setup systems (setup.rs)​

These run once on OnEnter(UiScreen::Sim), chained in order.

setup_lighting​

Spawns a DirectionalLight for the sun and a second for the moon, both visible on SCENE_LAYER and MAP_LAYER. Sun uses AMBIENT_DAYLIGHT illuminance; moon uses CIVIL_TWILIGHT.

setup_celestial​

Spawns the Earth entity and registers it in Celestials. Also spawns a scaled-down Map_Earth for the map view. Both use the 8K KTX2 Earth texture.

Registers both with keys "Earth" and "Map_Earth" in the Celestials resource.

setup_tether​

Spawns the tether joint chain. Creates NUM_TETHER_JOINTS rigid body entities each separated by DIST_BETWEEN_JOINTS metres, links them with TetherNode, and registers the root in OrbitalCache::tethers.

setup_entities​

Spawns the atmosphere, skybox, orbit camera, and initial debris/capture target entities. Also configures auto-exposure compensation curves and HDR bloom.

Propagation systems (propagation.rs)​

load_dataset_entities​

Schedule: OnEnter(UiScreen::Sim) (chained after setup systems)

Loads all JSON orbital datasets from assets/datasets/. For each JsonOrbital entry, registers the object in SpaceObjectCatalog and uploads ECI state data to the GPU buffer used by GpuComputePlugin.

init_orbitals​

Schedule: First (via OrbitalMechanicsPlugin)

Processes newly-spawned Orbit components. Converts TLE or classical elements into a brahe::KeplerianPropagator and stores it in the entity's Orbital component. Removes the Orbit component after initialisation.

cache_eci_states​

Schedule: ManualPhysics::First (via OrbitalMechanicsPlugin)

Iterates all entities with an Orbital component and calls propagator.state_eci(epoch) using the current WorldTime::epoch. Writes the resulting Vector6<f64> into OrbitalCache::eci_states so that downstream physics and algorithm systems can read ECI state without querying the propagator directly.

physics_bubble_add_remove​

Schedule: ManualPhysics::Prepare

Enables or disables the Avian3D RigidBody on each orbital entity based on its distance from the tether root. Bodies within PHYSICS_ENABLE_RADIUS get an active RigidBody; bodies outside PHYSICS_DISABLE_RADIUS have it removed. This prevents the physics solver from integrating objects that are too far away to interact with the tether.

target_entity_reset_origin​

Schedule: ManualPhysics::Prepare

Shifts the CameraTarget entity back toward the world origin when its position exceeds MAX_ORIGIN_OFFSET. Applies the same offset uniformly to all other entity transforms to preserve relative positions (floating origin step for physics).

floating_origin_update_visuals​

Schedule: Update

Syncs Bevy Transform positions for all orbital entities from their Avian3D physics Position (or from OrbitalCache::eci_states for inactive bodies), accounting for the current floating origin offset.

Camera systems (orbit_camera.rs)​

orbit_camera_input​

Schedule: Update

Reads mouse delta (right-click drag) and scroll wheel input. Updates OrbitCamera yaw, pitch, and distance for the active view.

orbit_camera_switch_target​

Schedule: Update

On left-click, raycasts into the scene. If an Orbital entity is hit, transfers CameraTarget to that entity.

orbit_camera_control_target​

Schedule: Update

Updates OrbitCamera::focus to match the current CameraTarget's world position.

orbit_camera_track​

Schedule: PostUpdate (after floating_origin_update_visuals)

Computes and applies the final camera Transform from OrbitCamera yaw/pitch/distance/focus.

User input systems (user_input.rs)​

toggle_map_view​

Toggles the active camera between scene view (SCENE_LAYER) and map view (MAP_LAYER) on M key press.

toggle_origin​

Toggles the floating origin debug marker visibility on O key press.

toggle_capture_gizmos​

Toggles Settings::capture_gizmos on the assigned key press, enabling or disabling capture force vector visualisation.

change_time_warp​

Adjusts WorldTime::multiplier on , / . key press.

map_orbitals​

Repositions map-view entity transforms based on current OrbitalCache::eci_states, scaled by MAP_UNITS_TO_M.

Physics systems (physics.rs)​

fixed_physics_step​

Schedule: FixedUpdate

Manually runs the ManualPhysics schedule at a fixed frequency (FIXED_HZ). This decouples all physics and orbital capture calculations from the frame rate, ensuring deterministic timesteps regardless of rendering load.

Capture algorithm systems (capture_algorithms.rs)​

capture_state_machine_update​

Schedule: ManualPhysics::Last

Advances the capture state machine for any entity carrying CaptureComponent. Each tick it:

  1. Looks up the CompiledCapturePlan from CapturePlanLibrary::compiled_plans.
  2. Evaluates all CompiledCaptureTransition conditions for the current state (distance and relative velocity bounds against values in OrbitalCache::eci_states).
  3. On a matching transition, switches CaptureComponent::current_state and records state_enter_time_s.
  4. Applies max_velocity and max_force constraints from CompiledCaptureStateParameters as Avian3D forces on the tether root joint.
  5. If the state carries a shrink_rate, decrements the tether joint separations each tick.

Gizmo systems (gizmos.rs)​

dev_gizmos​

Schedule: Update

Draws developer debug gizmos when Settings::dev_gizmos is true: floating origin sphere and physics-bubble radius around the camera target.

capture_gizmos​

Schedule: Update

Draws force vector gizmos for the active capture sequence when Settings::capture_gizmos is true.

orbital_gizmos​

Schedule: Last

Draws orbital path gizmos for all active Orbital entities in the map view layer.