Glossary

Glossary

Authoritative version: docs/14-glossary.md. Where a term is load-bearing, the canonical definition lives in the doc named below — link target is docs/.

Terms

Term	Definition	Doc
ActionTx	A signed action intent broadcast to peers: ⟨SequenceID, ActorID, Kind, Target, Payload, TickEpoch, Signature⟩. The unit of multiplayer traffic. Target is the address half, Payload the value half, and for a slab mutation the two together are exactly one delta record (A-03).	10
assetc	The asset compiler: parses authoring text, validates against schema, lowers to FlatBuffers/WASM data. Watch mode in dev, pack mode for release.	09
BVH	Bounding volume hierarchy over active SDFs, so a ray skips an entity in O(log N) unless it actually hits its coarse bounds.	04
Camera anchor	The integer world position local (f32) space is measured from this frame: P_local = P_global − C_global.	02
Causal order	The Lamport/HLC ordering of transactions inside an epoch; not wall-clock order.	10
Closed form	A rule whose state at any tick is computed directly, without stepping through intermediate ticks. What makes fast-forward legal.	05
Compaction	The epoch-commit step: bake outstanding deltas into a new genesis state, recompute roots, reset slab bump pointers. The LSM-tree analogy.	03
Circuit graph	The compiled topology of a connected wire network: nodes, zero-latency edges, transfer function f(I₁…Iₙ, t).	06
Delta mask (M_local)	The sparse set of player-authored differences from base state. The world's only memory of what the player did.	03
Delta record	The one u64 a slab appends: |16 region slot|36 intra-region (3×12 bits)|12 payload| — ADR-029's layout, drafted as contracts/delta.rs (A-03). It is the whole memory of an edit, and the only thing a replay needs to find the voxel it changed.	03
Determinism boundary	Simulation state is computed in Rust/WASM and never by a shader. ADR-017.	03
Domain deformation	Animation by warping the space an SDF is evaluated in, instead of moving vertices.	07
Epoch	One committed world state, identified by a root hash. The ledger is a sequence of epochs.	03
Event tag	A named, versioned macro-causal fact in the ledger (e.g. FlowBlocker{region, magnitude}). The canonical form of macro causality.	05
Field (macro)	A per-region scalar/vector (water table, fertility, population density) evolved by a rule with a declared jump method.	05
FlexBuffers	FlatBuffers' schema-free variant, for genuinely dynamic payloads.	09
Epoch root	The 32-byte BLAKE3 digest of one epoch's whole commitment: genesis ‖ slot table ‖ regions ‖ events, in that order, over the ADR-030 tree shape. What a peer sends a peer, and the only thing a desync check can compare. Published as a vector: EPOCH_0 91b97a52… agrees byte-for-byte on x86-64 Linux, x86-64 Windows and ARM64 macOS.	03
Fuel metering	WASM instruction budget per call; without it a mod's infinite loop freezes the client.	08
HDCS	64-bit Hierarchical Double-Origin Coordinate System — integer global space, float camera-relative space. ADR-016.	02
Hot reload	Edit a text asset or shader, see it in the running game without a restart.	09
Intensional commitment	Hashing the rule that generates a thing instead of its output. How ADR-030's tree shape handles base terrain: seed ‖ base_rule_id ‖ rule_version goes into the root, not the region's 2³⁶ unedited voxels. The cost is that a rule change invalidates every root — which is exactly the visibility the design wants.	03
Jump method	How a macro rule advances by Δt: closed_form, matrix_exp, integral, or iterative {cap}. Every rule must declare one.	05
Lazy evaluation	Nothing is computed until something needs it. The engine's answer to unloaded chunks.	01
Ledger	The append-only record of epochs, transactions and event tags. Holds roots and deltas — never block arrays.	03
Macro / micro	Macro = region-level fields evolved per epoch (cheap, simulated). Micro = voxels, entities, fluids in view (expensive, rendered).	05
Material function	A color/surface definition as a function of (p, n, t). No texture files exist in this project.	04
Mempool	Transactions committed but not yet compacted into an epoch.	03
Morton code	Z-order curve key for region traversal and octree indexing. Computed on RegionKey, never on raw voxel coordinates.	02
Node grammar	The declarative shape/material vocabulary (RoundedBox, SmoothUnion, Repeat, Voronoi…) interpreted by the master shader. ADR-012.	04
Octree root	A region's Merkle root derived from its children. Local, so edits don't re-hash the world.	03
Prompt-to-mod	In-game LLM authoring that emits RON + WGSL + WASM, then runs the same validation path as a hand-written mod.	08
Region	4096³ voxels, addressed by RegionKey (3×i64). The unit of the Merkle tree and of slab keying.	02
Region slot	One epoch's temporary 16-bit index for a region, assigned in first-touch order, held in the epoch header and rebuilt deterministically at replay — what a delta record carries so the 3×i64 region key itself never has to be packed. At most 65,536 distinct regions per epoch record stream.	02
RON	Rusty Object Notation — the canonical in-repo authoring format (comments, trailing commas, maps 1:1 to structs).	09
Rollback	Reverting an optimistic local edit by storing its previous u64 back into its slab slot.	10
SDF	Signed distance function: negative inside, zero at surface, positive outside. The only geometry primitive.	04
Sector	16³ regions; the granularity of named event tags.	02
Slab	Per-region append-only record buffer (since ADR-029), pre-allocated and contiguous. Writes are O(1) appends; resets are bump-pointer → 0. Its geometry and capacity are unsettled (SPEC-06, measured by spike S2), its addressing is not.	03
Sphere tracing	Raymarching where each step equals the SDF value — a guaranteed-empty distance.	04
Tree shape	The arity, child order, empty-node rules and integer byte order that turn a digest into a root. ADR-028 chose the hash and deliberately did not choose this; ADR-030 and A-10 (contracts/tree.rs, frozen 2026-10-12) do, and crates/ledger executes it. Two peers agreeing on BLAKE3 but disagreeing on the shape compute different roots and neither errors.	03
Watch-list	A region's registered interest in another region's field, for continuous drain/refill relationships.	10
WIT	WASM Interface Types — the typed contract between the host engine and mods.	08

Symbols

Symbol	Meaning
S_base, S_epoch	committed base state at an epoch
M_local	the sparse delta mask of pending edits
M_active, M_cold	hot (VRAM, in interaction radius) and cold (RAM write-ahead) slab tiers
⊕	apply-overlay: base state overridden by the delta mask
f(pos, t)	procedural evaluation of base state at position and tick
N = ∇SDF(p)	surface normal via central differences (6 evaluations)
Δt	elapsed ticks between an epoch and now — ambiguous in the source, must be declared per rule (OQ-42)
EpochHash	MerkleHash(BaseGenesisRoot ⊕ CommittedSlabs) — the 32-byte world-equality proof
ω, φ	clock frequency and phase in ⌊(t + φ)·ω⌋ mod 2
C_global	camera anchor in global integer space

Abbreviations

ADR	architecture decision record
CA	cellular automaton
DoD	definition of done — a gate list (doc 11)
GI	global illumination
GS	the source design transcript — cited only as GS <line>; it stays outside the repository
HLC	hybrid logical clock
LOD	level of detail
LRU	least-recently-used eviction
LSM	log-structured merge-tree (the RocksDB/LevelDB analogy)
OQ	open question (doc 13)
P0/P1/P1.5/P2	roadmap phases (doc 11)
SPEC	internal contradiction in the design register (doc 13)
SVO	sparse voxel octree — the original delta-mask storage idea, superseded by slabs
TPS	ticks per second — the server-lag metric Minecraft-style engines are judged by