Coding Style

The conventions the code base actually follows, checked against the tree on 2026-11-10. There is no formatter: follow the surrounding file.

Language and layout

• C++23 (CMAKE_CXX_STANDARD 23, required). [[nodiscard]], constexpr, noexcept and enum class are used freely.
• There is no .clang-format or .editorconfig. Every header starts with #pragma once; indentation is four spaces.
• Brace style differs by area: src/GalaxyEggbert/Game/, Editor/ and the host (src/GalaxyEggbertCNA/) put braces on their own line; the voxel container in include/GalaxyEggbert/Worlds/ opens namespace GalaxyEggbert::Worlds { on the same line and documents its API with Doxygen /** @brief ... */ blocks.

Namespaces

Header-only helpers often get a nested namespace of their own: Game::CratePush, Game::BrickEdges, Game::TextMetrics, Editor::AutoTile.

Naming

• Types and member functions are PascalCase (BlupiController::SettleOnGround, WorldRuntime::TryActivateSwitch), except the voxel container, whose member functions are lower camel case (World::getBlock, saveToFile, blockChangesSince).
• Constants start with k: kMoveSpeed, kCheatsEnabled, kSolidBigDecorIcons.
• Data members come in two styles: a trailing underscore (phase_; the host, the editor, InputPad, SaveData, WorldRuntime, World) and an m_ prefix (m_yaw; BlupiController, TerrainRenderer, CameraShake, the shader and effect classes). Use the one the file uses.
• No GE prefix on game-owned or editor-owned names. The classes were renamed (GEWorldRuntime is WorldRuntime, GETerrainRenderer is TerrainRenderer, and so on). A few historic names keep it: the verifier executables VerifyGE..., the CMake variable GE_SHARED_SOURCES, the object library GEEditorVerifySupport and the function ge_add_editor_verify. Do not add new ones, and do not rename those without a reason.

Headers and dependencies

• Public engine-independent headers live in include/GalaxyEggbert/ and are included as <GalaxyEggbert/...>; sibling headers inside src/GalaxyEggbert/Game/ as "...".
• No CNA or cna-engine include in include/GalaxyEggbert/ or src/GalaxyEggbert/Worlds/. These use plain floats and standard types, so the world model can be tested without a graphics context.
• Many rules are header-only helpers: 45 of the 80 headers in src/GalaxyEggbert/Game/ have no .cpp (for example CratePush.hpp, TerrainLighting.hpp, TileCoverage.hpp, DebugOverlay.hpp, FocusNavigator.hpp, SceneEffectsLogic.hpp). Pure inline/constexpr functions with no GPU make a cheap Verify* test possible; prefer that shape for new logic.
• Per-type facts belong in the two registries (BlockDefinitionRegistry, ObjectDefinitionRegistry), not in switch statements spread over files.

Comments cite the original and the ledgers

Comments in this code base are long and carry dates and ids. When you copy behaviour from the original, cite the reference file and line; when you deviate, say so and point at the ledger row. A real example, from src/GalaxyEggbert/Game/CratePush.hpp:

namespace GalaxyEggbert::Game::CratePush
{
    // How Blupi moves a crate (ObjectType12), from Mobile Eggbert's Decor.cpp (2026-11-01, the
    // fidelity audit's GP-crate rows, plans/audit/behavior_differences.md BD-0001):
    //
    // - While pushing (action Push) he walks CaisseGetMove(5) pixels a 20 Hz tick
    //   (Decor.cpp:3388/3446); while pulling (Pop) he backs away CaisseGetMove(3) (:3410/3468).
    ...
    // The original's 64-pixel block is one Galaxy cell.
    inline constexpr float kPixelsPerCell = 64.0f;
    inline constexpr float kOriginalTicksPerSecond = 20.0f;
    ...
    // A 3D adaptation (M3D-0002): a crate that cannot go only because it lies off the lane of its
    // move by up to this much across ... first slides into the lane, at the same speed.

When you change behaviour that a comment documents, fix the comment. Some long comments (for example at the top of SaveData.hpp and GalaxyEggbertGame.hpp) describe earlier states; trust the code and the ledgers over them.

Determinism

The simulation runs on a fixed 1/60 s tick, and the golden trace, the autoplay playthroughs, the demo replays and the resume feature all depend on it replaying identically. No wall-clock time, unseeded randomness or frame-rate dependence in the simulation. Presentation-only work (the 3D effects, interpolated drawing above 60 frames a second) must leave the simulation untouched.

Generated files and stable IDs

Python

• Python 3, run from the repository root with python3 tools/...; paths are resolved from __file__; options via argparse.
• A module docstring says what the tool does, how to run it and which brief or ledger it serves (see tools/levelcheck.py or tools/worlds/world012.py). Some modules, such as tools/worldkit.py, start with from __future__ import annotations; most world generators do not.
• World generators import the kits with the sys.path.insert(...) + # noqa: E402 pattern and seed any randomness (random.Random(12) in world012.py), so the output is byte-for-byte reproducible.
• Third-party dependencies are limited to numpy and Pillow; Blender and ffmpeg are used as external programs by some asset tools.

Shell

bash with set -u (or set -euo pipefail), a header comment with the usage that the script prints when called without arguments (sed -n '2,12p' "$0"), paths derived from BASH_SOURCE, and scratch output in the git-ignored build-probe/ directory of the repository, never /tmp.

Related pages

• Development: rules, ledgers and commit messages
• Testing & QA: how to add a Verify* test
• Project Structure