From aaeb4b1b8d00a08ae09bb6d6552a5614ec46cbd2 Mon Sep 17 00:00:00 2001 From: cinnaboot Date: Sat, 24 Jan 2026 14:45:12 -0500 Subject: [PATCH] add session summary --- ...-24-unified-orbital-elements-phases-1-3.md | 90 +++++++++++++++++++ 1 file changed, 90 insertions(+) create mode 100644 docs/session_summaries/2026-01-24-unified-orbital-elements-phases-1-3.md diff --git a/docs/session_summaries/2026-01-24-unified-orbital-elements-phases-1-3.md b/docs/session_summaries/2026-01-24-unified-orbital-elements-phases-1-3.md new file mode 100644 index 0000000..5206b3e --- /dev/null +++ b/docs/session_summaries/2026-01-24-unified-orbital-elements-phases-1-3.md @@ -0,0 +1,90 @@ +# Session Summary - 2026-01-24 + +## Overview +Implemented Phases 1-3 of unified orbital elements configuration system. + +## Changes Made + +### Phase 1: Create Orbital Mechanics Module +- **Created** `src/orbital_mechanics.h` - Defines `OrbitalElements` struct with Keplerian elements +- **Created** `src/orbital_mechanics.cpp` - Implements `orbital_elements_to_cartesian()` conversion function +- Supports all orbit types: circular (e=0), elliptical (01) +- Planar orbits only (inclination=0), 3D orientation deferred to future work + +### Phase 2: Update Data Structures +- **Modified** `CelestialBody` struct (simulation.h): + - Added `OrbitalElements orbit` field + - Renamed `position` → `global_position` + - Renamed `velocity` → `global_velocity` + - Reorganized field order for clarity + +- **Modified** `Spacecraft` struct (spacecraft.h): + - Added `OrbitalElements orbit` field + - Renamed `position` → `global_position` + - Renamed `velocity` → `global_velocity` + +- **Renamed** `OrbitalElements` → `OrbitalMetrics` in simulation.h (output/analysis use case) + - Updated all references in `simulation.cpp`, `config_loader.cpp`, `renderer.cpp`, `ui_renderer.cpp` + +### Phase 3: Update Config Parser +- **Modified** `parse_toml_body()` (config_loader.cpp): + - Replaced old `position` field requirement with `orbit` table parsing + - Removed old `eccentricity` and `semi_major_axis` top-level fields + - Parses all orbital element fields with defaults + - Supports `altitude` convenience field for LEO/GEO orbits + - Required: `semi_major_axis` or `altitude` in orbit table + - Optional: `eccentricity` (default 0.0), `true_anomaly` (default 0.0), 3D orientation elements (default 0.0) + - Position/velocity initialized to zero (calculated from orbital elements later) + +- **Modified** `parse_toml_spacecraft()` (config_loader.cpp): + - Replaced `position` + `velocity` fields with `orbit` table parsing + - Uses same orbital element parsing logic as bodies + - Position/velocity initialized to zero (calculated from orbital elements later) + +- **Added** validation for orbital elements: + - `semi_major_axis` must not be zero + - `eccentricity` must be >= 0 + - For elliptical orbits (e < 1): `semi_major_axis > 0` + - Validates both bodies and spacecraft + +- **Modified** `load_spacecraft_from_toml()`: + - Removed manual position/velocity calculation from parent + - Now initializes both bodies and spacecraft in `initialize_orbital_objects()` + +## Commits +1. **dc1f9f4** - Phase 1: Create orbital mechanics module +2. **121f1b9** - Phase 2: Update data structures with global_position/global_velocity +3. **ec1d115** - Phase 3: Update config parser to use orbital elements + +## Net Line Count +- **+172 lines added** (orbital_mechanics module, updated structs, config parsing, validation) +- **-93 lines deleted** (removed manual velocity calculations, old config format support) + +## Remaining Issues +1. **Phase 4 incomplete**: Need to update initialization to use `orbital_elements_to_cartesian()` function + - Current state: `add_body_to_simulation()` calls old `calc_orbital_velocity()` (removed) + - Old `initialize_bodies()` function still references removed function + - Need to replace with `initialize_orbital_objects()` that calls `orbital_elements_to_cartesian()` + +2. **Function name typo**: File has `orbital_mechanics.h` but code uses `calc_orbital_velocity` (should be `orbital` not `orbi`) + +3. **Config format**: All existing test configs need to be updated to new `orbit` table format (13 config files) + +4. **Renderer references**: Need to verify all `render_orbit()` calls are correct after struct changes + +## Next Steps (Phase 4) +1. Remove old `calc_orbital_velocity()` function from simulation.cpp +2. Implement `initialize_orbital_objects()` using `orbital_elements_to_cartesian()`: + - Bodies: Convert orbital elements to local position/velocity, compute global coordinates + - Spacecraft: Handle altitude convenience, add parent radius, convert to local/global coordinates + - Calculate SOI radii for bodies +3. Update `load_system_config()` to call `initialize_orbital_objects()` instead of `initialize_bodies()` +4. Update all 13 test configs to new format with `orbit` tables +5. Verify renderer displays orbits correctly +6. Run full test suite to ensure all changes work correctly + +## Notes +- All orbital calculations use planar orbits (inclination=0), 3D orientation deferred +- `OrbitalElements` struct in separate module to enable clean separation of concerns +- Config parser now validates orbital elements at load time (better error messages) +- Altitude convenience simplifies LEO/GEO orbit specification (e.g., altitude=400km instead of semi_major_axis calculation)