Hey everyone — MrPhil here with a major development update for Stellar Throne, my sci-fi 4X strategy game.

This week I finished implementing all 21 simulation phases in Zig and brought the parity testing framework online to compare Zig vs. Godot turn-by-turn. The Zig engine is feature-complete at the phase level, but there are still parity differences to resolve before it becomes the default runtime.

🧠 Dual-Engine Architecture (Why Two Engines?)

• Godot handles the UI, visualization, and input.

• Zig runs the high-performance simulation of empires, colonies, economies, and galactic systems.

The goal is to keep Godot flexible while Zig delivers raw simulation speed — both verified through automated parity testing.

⚙️ Track Two Wrap-Up: 21 Phases Implemented

At the start of the week, only a few phases were functional. By the end, all 21 simulation phases were implemented and validated at the unit level.

Highlights:

• Population growth, colony development, infrastructure maintenance

• Resource extraction and production chains

• Fleet movement and logistics

• Natural disasters and random events

• Quest system and narrative progression

• Diplomacy drift, relationship updates, and victory conditions

• Military combat resolution and research progression

• Final integration phase that ties everything together

Each phase includes validation tests to ensure predictable behavior.

🧩 Real Data via TOML (No More Magic Numbers)

I ported the TOML configuration system so the simulation now loads real game data:

• load_gameplay() — balance parameters and constants

• load_resources() — economy definitions and production chains

• load_content() — events, quests, and narrative triggers

This added 800 + lines of Zig, replacing thousands of hard-coded values.
On the Godot side, the Research Manager migrated from JSON to TOML for consistency.

🧪 Test Suite Rehab + Fixes

The Zig test suite had bit-rotted (wrong layout, 91 compile errors).
I:

• Reorganized tests under src/tests

• Wrote a test health monitor script

• Fixed 11 failing tests (RNG distribution, TOML table arrays, event weighting, colony growth, diplomacy drift)

✅ All Zig tests now pass.

🌉 Godot ↔ Zig Bridge + Parity Harness

Built the Turn Simulation Service in Godot:

1. Serialize state to JSON

2. Run a turn in Zig

3. Deserialize results back into Godot

Added:

• Runtime engine toggle (Godot ↔ Zig A/B testing)

• Parity testing framework that runs identical turns in both engines and compares every field across 10–100 empires and 10–250 systems

🔎 What Parity Testing Found (Work in Progress)

• Godot and Zig diverge slightly on population growth and stability formulas.

• Some mismatches come from floating-point drift and minor logic differences.

So, while Zig has feature parity at the phase level, behavioral parity is not yet complete.

⚡ Performance Snapshot

In large galaxy tests, the Zig simulation ran ≈ 52.7× faster than Godot.

📈 Commits at a Glance

✅ Current Status

• ✅ All 21 phases implemented in Zig

• ✅ All Zig tests passing

• ✅ TOML data loader integrated

• ✅ Parity testing framework online

• 🚧 Parity differences remain to be resolved

• 🚧 Zig engine not default yet

🔭 Next Steps

• Fix remaining parity gaps (population, stability, diplomacy)

• Reduce floating-point variance

• Once identical outputs are confirmed, switch to Zig as default for full performance gain

That’s this week’s devlog — thanks for reading!
Follow progress and upcoming milestones at mrphilgames.com.

— MrPhil