Merge pull request 'gmp(M02): extract player terrain query' (#23 ) from work/sindo-main-codex/m02-terrain-query into master

Reviewed-on: #23
docs(M02): publish terrain query handoff
2026-07-14 22:17:12 +03:00 · 2026-07-14 23:11:23 +04:00 · 2026-07-14 23:10:55 +04:00
14 changed files with 846 additions and 113 deletions
@@ -0,0 +1,118 @@
 # M02-GMP-TERRAIN-QUERY-001 — Player terrain query boundary
 <!-- OPENWC_CLAIM:M02-GMP-TERRAIN-QUERY-001:sindo-main-codex:2026-07-16 -->
 <!-- OPENWC_HANDOFF:READY:M02-GMP-TERRAIN-QUERY-001:a45d521 -->
 ## Ownership
 - Target: M02
 - Program: GMP/RND
 - Owner/Agent ID: sindo-main-codex
 - Branch: `work/sindo-main-codex/m02-terrain-query`
 - Lease expires UTC: 2026-07-16
 - Integrator: M02 milestone integrator
 ## Outcome
 Introduce a typed `TerrainQuery` boundary and move ADT loading, caching, chunk
 selection and height interpolation out of `ThirdPersonWowController` without
 changing current spawn/ground-snap behavior.
 ## Non-goals
 - Change ADT topology, coordinate formulas, terrain mesh or renderer caches.
 - Add physics collision, slopes, water, jump/fall/swim or server movement.
 - Reuse the streaming renderer cache before its public terrain-query contract exists.
 - Extract camera or character presentation.
 - Mark M02 complete or edit its checklist/Evidence.
 ## Paths
 - Exclusive: `src/gameplay/terrain/`, `src/tools/verify_terrain_query.gd`,
  `docs/modules/terrain-query.md`, this claim
 - Shared/hotspots: `src/scenes/player/third_person_wow_controller.gd`,
  `src/tools/verify_player_input.gd`,
  `src/tools/verify_coordinate_conversion_boundaries.gd`,
  `docs/modules/local-player-movement.md`,
  `docs/modules/README.md`
 - Generated/ignored: local `.godot`, native DLL, generated ADT resources and renderer corpus
 ## Contracts and data
 - Public API: `TerrainQuery.sample_ground_height(GodotWorldPosition)` returning
  immutable `TerrainGroundSample`
 - Production adapter: `AdtTerrainQuery` with owned per-tile parse cache
 - Test/data-source seam: optional ADT tile loader callable at construction
 - Coordinate contract version, ADT format, renderer cache and persistence: unchanged
 - Consumers: current player scene; future movement/collision policies
 ## Dependencies
 - Requires: merged movement controller on master `5206c42`
 - Blocks: camera/presentation extraction from the player hotspot
 - External state: production uses existing native `ADTLoader`; synthetic tests need no proprietary data
 ## Verification
 - Commands: synthetic height/cache/failure verifier, player input/movement
  regressions, asset-free scene, coordinate/StreamingFocus gates, renderer dry-run
  and repository gates
 - Fixtures: synthetic 145-height chunk payload and injected flat terrain query
 - Fidelity evidence: preserves existing outer-grid bilinear interpolation,
  spawn ground offset and per-tick snap formula only
 - Performance budget: one cached tile lookup and local interpolation per ground query;
  no new I/O after first tile load
 ## Documentation deliverables
 - Inline public API docs for query, sample and ADT adapter
 - Terrain-query module spec with inputs/outputs, data-flow, cache lifecycle and sequence diagrams
 - Updated movement/coordinate consumer boundaries, source maps and module registry
 ## Simplicity and naming
 - Important names: `TerrainQuery`, `TerrainGroundSample`, `AdtTerrainQuery`
 - Simplest approach: one narrow query contract, one typed result and one existing-format adapter
 - Rejected complexity: general collision framework, terrain service locator and renderer-cache coupling
 - Unavoidable complexity: ADT 145-height layout and chunk lookup stay isolated in adapter
 - Measured optimization evidence: existing per-tile cache retained; no new optimization
 ## Status
 - State: ready-for-review
 - Done: typed query/sample contract, cached ADT adapter, player migration,
  synthetic interpolation/cache/failure tests, injected scene regression and documentation
 - Next: M02 integrator reviews and merges before camera-rig extraction
 - Blocked by:
 ## Handoff
 - Commit: `a45d521`
 - Branch: `work/sindo-main-codex/m02-terrain-query`
 - Outcome: `ThirdPersonWowController` no longer loads ADTs, caches tile
  dictionaries, selects chunks or interpolates height grids. It consumes a
  replaceable typed `TerrainQuery` and retains only existing offset/snap policy.
 - Public contracts: additive immutable `TerrainGroundSample`, replaceable
  `TerrainQuery`, cached `AdtTerrainQuery` and player `set_terrain_query`.
  Coordinate contract version, ADT/native format and renderer caches are unchanged.
 - Verification: `TERRAIN_QUERY PASS contract=4 interpolation=1 cache=1
  failures=2 player_injection=1`; player-input and local-movement regressions
  passed; asset-free scene exited `0`; coordinate boundary passed with five
  required consumers and StreamingFocus passed; renderer dry-run passed eight
  pre-capture gates and seven checkpoint plans; coordination/documentation/diff gates passed.
 - Fidelity: synthetic fractional-grid fixture locks the inherited 145-height
  outer-grid bilinear result within `0.002` Godot units; injected scene locks
  spawn offset `0.05` and physics snap. This is sandbox-regression evidence,
  not build-12340 triangle/hole/collision parity.
 - Local verification inputs: isolated worktree reused the existing ignored
  native DLL and generated ADT resource scripts. Proprietary extracted data and
  character GLB were absent, so renderer dry-run logged expected missing-corpus
  diagnostics while all contract steps returned success.
 - Rebuild/migration: none; caches are transient and existing formats remain unchanged.
 - Remaining risks: first ADT parse remains synchronous as before; unavailable
  tiles cache until query replacement; player still owns snap policy; exact
  ADT triangle choice, holes, slopes, liquids and collision remain open.
 - Documentation: inline public APIs plus `docs/modules/terrain-query.md` with
  inputs/outputs, data-flow, cache state and cross-boundary sequence diagrams,
  ownership, failure/recovery, capability status and source map. Coordinate and
  movement consumer specifications were updated.
@@ -11,6 +11,7 @@
 | Domain identities | Implemented contract | [`domain-identities.md`](domain-identities.md) |
 | Player input | Partial | [`player-input.md`](player-input.md) |
 | Local player movement | Implemented | [`local-player-movement.md`](local-player-movement.md) |
 | Terrain query | Implemented | [`terrain-query.md`](terrain-query.md) |
 | Renderer | Partial | [`world-renderer.md`](world-renderer.md), [`../../RENDER.md`](../../RENDER.md) |
 | Network/session | Planned | [`../../targets/roadmap/03-network-and-session.md`](../../targets/roadmap/03-network-and-session.md) |
 | Gameplay | Prototype/Planned | [`../../targets/roadmap/04-gameplay-systems.md`](../../targets/roadmap/04-gameplay-systems.md) |
@@ -5,9 +5,9 @@
 | Field | Value |
 |---|---|
 | Status | Implemented |
-| Target/work package | `M01-FND-COORDS-001`, `M01-FND-COORD-TILE-AXIS-002`, `M01-QAR-COORD-FIXTURES-001`, `M01-FND-COORD-BOUNDARY-GATE-001`, `M01-QAR-SERVER-SPAWN-RENDERER-001` |
+| Target/work package | `M01-FND-COORDS-001`, `M01-FND-COORD-TILE-AXIS-002`, `M01-QAR-COORD-FIXTURES-001`, `M01-FND-COORD-BOUNDARY-GATE-001`, `M01-QAR-SERVER-SPAWN-RENDERER-001`, `M02-GMP-TERRAIN-QUERY-001` consumer migration |
 | Owners | Foundation/domain |
-| Last verified | Worktree `work/sindo-main-codex/m01-server-spawn-renderer`, 2026-07-13 |
+| Last verified | `a45d521`, 2026-07-14 |
 | Profiles/capabilities | All profiles; contract version 2 |
 ## Purpose
@@ -86,7 +86,7 @@ Forbidden dependencies:
 | Input | `AdtPlacementPosition` | Future ADT adapter | `CoordinateMapper` | Immutable caller value | Any thread, call duration |
 | Input | `CanonicalWowWorldPosition`, `CanonicalWowWorldYaw` | Gameplay/content/domain | `CoordinateMapper` | Immutable caller value | Any thread, call duration |
 | Output | `CanonicalWowWorldPosition` | `CoordinateMapper` | Gameplay/content/adapters | New immutable value | Caller-owned reference |
-| Output | `AdtTileCoordinate`, `AdtTileLocalPosition`, `AdtChunkCoordinate` | `CoordinateMapper` | Streaming/content adapters | New immutable values | Caller-owned references |
+| Output | `AdtTileCoordinate`, `AdtTileLocalPosition`, `AdtChunkCoordinate` | `CoordinateMapper` | Streaming/content/terrain-query adapters | New immutable values | Caller-owned references |
 | Output | `GodotWorldPosition`, `GodotWorldYaw` | `CoordinateMapper` | Future render/scene adapter | New immutable values | Caller-owned references |
 | Test input | `coordinate_golden_points.json` schema 1 | Pinned public server row plus private numeric observations | Headless fixture verifier | Versioned repository fixture | Test-process lifetime |
@@ -115,6 +115,10 @@ flowchart LR
    Canonical -->|half extent - Y; Z; half extent - X| Godot[GodotWorldPosition]
    Godot -->|typed direct adapter| Tile
    Godot -->|typed direct adapter| Local
    Godot --> TerrainQuery[AdtTerrainQuery consumer]
    TerrainQuery --> Tile
    TerrainQuery --> Local
    TerrainQuery --> Chunk
    Tile -->|tile plus local| Godot
    ServerYaw[ServerWorldYaw] -->|normalize only| CanonicalYaw[CanonicalWowWorldYaw]
    CanonicalYaw -->|same numeric world angle| GodotYaw[GodotWorldYaw]
@@ -185,7 +189,8 @@ raw three-number arrays are not an accepted new persistence contract.
 - Boundary enforcement: `src/tools/verify_coordinate_conversion_boundaries.gd`.
 - Server-spawn renderer contract: `src/tools/verify_server_spawn_renderer.gd`
  validates the dedicated manifest against the same pinned fixture before GUI capture.
- Integration/E2E: sky, player, streamer and terrain probe use mapper boundaries;
+- Integration/E2E: sky, player spawn, streamer, terrain probe and the extracted
  `AdtTerrainQuery` use mapper boundaries;
  `StreamingFocus` provides typed renderer focus, and the pinned AzerothCore
  Human Warrior spawn is captured in the Eastern Kingdoms renderer at ADT
  `(32,48)`, chunk `(3,12)`.
@@ -243,6 +248,7 @@ raw three-number arrays are not an accepted new persistence contract.
 | `src/tests/fixtures/coordinate_golden_points.json` | Versioned cross-source values, provenance and tolerances |
 | `src/tools/verify_coordinate_golden_fixtures.gd` | Cross-source fixture schema and mapper validation |
 | `src/tools/verify_coordinate_conversion_boundaries.gd` | Repository-wide manual conversion and required-consumer gate |
 | `src/gameplay/terrain/adt_terrain_query.gd` | Typed Godot-position consumer for ADT tile/local/chunk lookup |
 | `src/tools/server_spawn_render_manifest.json` | Pinned server-spawn camera, player, marker and expected ADT ownership |
 | `src/tools/verify_server_spawn_renderer.gd` | Fixture-to-renderer manifest contract verifier |
 | `docs/adr/0001-canonical-world-coordinates.md` | Normative axes, units, boundaries and rollout decision |
@@ -7,7 +7,7 @@
 | Status | Implemented |
 | Target/work package | M02 / M02-GMP-MOVEMENT-001 |
 | Owners | Gameplay local movement state; scene composition owns the instance |
-| Last verified | `435e1c9`, 2026-07-14 |
+| Last verified | `a45d521`, 2026-07-14 |
 | Profiles/capabilities | Current render sandbox; production/debug profile gate pending |
 ## Purpose
@@ -37,7 +37,7 @@ flowchart LR
    Scene[ThirdPersonWowController] --> Basis
    Displacement --> Scene
    Scene --> Transform[Player world transform]
-    Scene --> Terrain[Ground snap adapter]
+    Scene --> Terrain[TerrainQuery and ground snap adapter]
    Velocity --> Presentation[Visual facing and animation adapter]
 ```
@@ -153,7 +153,7 @@ sequenceDiagram
 | Negative physics delta | `advance` guard | Returns zero displacement; velocity unchanged | Unit regression | Resume with valid non-negative delta |
 | Missing scene basis owner | Scene composition defect | Controller cannot be called correctly | Scene/parser error or boundary test | Restore explicit scene dependency |
 | Flight toggle during motion | Command path | Velocity clears before next step | State-transition regression | Continue from zero velocity |
-| Missing terrain data | Outside module | Scene skips existing ground snap | Existing terrain diagnostics | TerrainQuery extraction will own policy |
+| Missing terrain data | `TerrainGroundSample.is_available == false` | Scene skips existing ground snap | Stable terrain failure code | Replace/recover query backend |
 There is no asynchronous cancellation, retry or rollback. Recreating the
 controller resets velocity and flight state deterministically.
@@ -211,7 +211,8 @@ separate versioned movement snapshot contract.
 | Scene-free local velocity state | Implemented | Pure controller and source boundary regression | Integrate target checklist after review |
 | Existing planar acceleration/speeds | Implemented | Exact numeric unit cases and real scene regression | Compare with build 12340 before fidelity claim |
 | Existing camera-relative free flight | Implemented | Pitched-basis and toggle/reset cases | Restrict to sandbox profile |
-| Terrain/collision movement policy | Planned | Outside module by design | Extract `TerrainQuery` next |
+| Terrain height query | Implemented | Typed `TerrainQuery` and injected player regression | Ground-snap policy remains scene-owned |
 | Terrain collision movement policy | Planned | Height-only query does not model collision | Add slopes/holes/collision later |
 | Jump/fall/swim | Planned | M02/M09 roadmap | Requires terrain/liquid and server contracts |
 | Prediction/reconciliation | Planned | M08/M09 roadmap | Requires movement snapshot/network contract |
@@ -220,7 +221,8 @@ separate versioned movement snapshot contract.
 - Numeric defaults preserve the existing sandbox but are not original-client evidence.
 - Configuration is captured at scene `_ready`; runtime mutation of exported speed
  properties does not reconfigure an existing controller.
- Ground snap remains in the player scene until `TerrainQuery` extraction.
+- Ground snap remains in the player scene, but its ADT data access is now behind
  a replaceable `TerrainQuery`.
 - Sprint and free flight still lack a typed sandbox capability gate.
 - The module uses Godot math value types; a future engine-independent gameplay
  predictor may require scalar/domain movement contracts.
@@ -230,6 +232,7 @@ separate versioned movement snapshot contract.
 | Path | Responsibility |
 |---|---|
 | `src/gameplay/movement/local_player_movement_controller.gd` | Owned velocity/flight state and deterministic integration |
 | `src/gameplay/terrain/terrain_query.gd` | Replaceable ground-height input boundary |
 | `src/scenes/player/third_person_wow_controller.gd` | Composition, basis selection, displacement/terrain/presentation adapters |
 | `src/tools/verify_local_player_movement.gd` | Pure numeric, state-transition and dependency regression |
 | `src/tests/scenes/player_input_regression.tscn` | Asset-free integrated player fixture |
@@ -0,0 +1,251 @@
 # Terrain Query
 ## Metadata
 | Field | Value |
 |---|---|
 | Status | Implemented |
 | Target/work package | M02 / M02-GMP-TERRAIN-QUERY-001 |
 | Owners | Gameplay terrain-query contract; ADT adapter owns parsed tile cache |
 | Last verified | `a45d521`, 2026-07-14 |
 | Profiles/capabilities | Current sandbox ADT ground height; renderer/physics backend planned |
 ## Purpose
 Provide a replaceable, scene-free ground-height query for player movement.
 Isolate native ADT loading, per-tile caching, chunk selection and legacy outer
 height-grid interpolation from the player scene behind a typed
 `GodotWorldPosition → TerrainGroundSample` contract.
 ## Non-goals
 - Own player transforms, movement velocity or ground-snap policy.
 - Provide collision normals, slopes, holes, liquids, WMO/M2 collision or ray queries.
 - Change ADT topology, coordinate conversion, renderer caches or native parser format.
 - Claim original-client terrain-contact parity from height regression alone.
 - Couple gameplay to the monolithic streaming renderer before a public backend exists.
 ## Context and boundaries
 ```mermaid
 flowchart LR
    Scene[ThirdPersonWowController adapter] --> Position[GodotWorldPosition]
    Position --> Contract[TerrainQuery]
    Contract --> Adapter[AdtTerrainQuery]
    Adapter --> Mapper[CoordinateMapper]
    Adapter --> Native[ADTLoader]
    Native --> Tile[ADT tile Dictionary]
    Tile --> Cache[Owned tile cache]
    Cache --> Sample[TerrainGroundSample]
    Sample --> Scene
    Scene --> Snap[Existing ground-snap policy]
 ```
 Allowed dependencies:
 - Typed `GodotWorldPosition` and `CoordinateMapper` contracts.
 - Existing native `ADTLoader` at the ADT adapter boundary.
 - Dynamic dictionaries only inside the native-format adapter.
 - Player scene composition may inject any `TerrainQuery` implementation.
 Forbidden dependencies:
 - `TerrainQuery` contract depending on Nodes, cameras, input or renderer state.
 - Player scene loading/parsing ADT data or owning a parsed tile cache.
 - Manual WoW/Godot/ADT world-coordinate conversion outside `CoordinateMapper`.
 - Terrain query mutating transforms, gameplay movement state or visual meshes.
 ## Public API
 | Symbol | Kind | Purpose | Thread/lifetime | Errors |
 |---|---|---|---|---|
 | `TerrainGroundSample.available(height_units)` | Immutable value factory | Creates a finite Godot-world ground height | Any thread; caller-held value | Non-finite height becomes unavailable |
 | `TerrainGroundSample.unavailable(failure_code)` | Immutable value factory | Creates explicit unavailable result | Any thread; caller-held value | Empty code normalizes to `terrain_unavailable` |
 | `TerrainQuery.sample_ground_height(position)` | Replaceable boundary | Samples ground at typed Godot world position | Implementation-defined; current adapter main-thread owned | Base reports `terrain_query_not_implemented` |
 | `AdtTerrainQuery.new(extracted_directory, map_directory_name, loader_override)` | Adapter constructor | Configures one map and optional test/data-source loader | Query lifetime | Production validates native loader and file presence lazily |
 | `AdtTerrainQuery.sample_ground_height(position)` | Adapter method | Loads/caches tile and interpolates ADT outer heights | Main thread; cache lives with query | Returns stable failure code |
 | `ThirdPersonWowController.set_terrain_query(query)` | Composition method | Replaces terrain backend independently of movement/presentation | Call before scene ready or on main thread | Null is rejected and current query retained |
 ## Inputs and outputs
 | Direction | Contract/data | Producer | Consumer | Ownership | Thread/lifetime |
 |---|---|---|---|---|---|
 | Input | `GodotWorldPosition` | Player scene adapter | `TerrainQuery` | Immutable caller-held value | One query |
 | Input | Extracted directory/map name | Scene composition | `AdtTerrainQuery` | Copied strings | Query lifetime |
 | Input | ADT file/dictionary | Filesystem/native loader or injected loader | `AdtTerrainQuery` | Adapter-owned cached dictionary | Query lifetime |
 | Output | `TerrainGroundSample` | Terrain query | Player ground-snap adapter | Immutable caller-held value | One query |
 | Output | Failure code | Terrain query | Diagnostics/tests | Immutable `StringName` | Sample lifetime |
 Side effects:
 - Production adapter performs lazy file existence check and native ADT parse on first tile query.
 - Adapter mutates only its per-query tile/failure caches.
 - No scene tree, transform, renderer RID, network, database or persisted setting mutation occurs.
 ## Data flow
 ```mermaid
 flowchart LR
    Position[GodotWorldPosition] --> TileCoord[CoordinateMapper tile/local/chunk]
    TileCoord --> Lookup{Tile cached?}
    Lookup -->|no| Load[ADTLoader or injected loader]
    Load --> Cache[Cache Dictionary or unavailable result]
    Lookup -->|yes| Cache
    Cache --> Chunk[Select MCNK by origin]
    Chunk --> Heights[Validate 145 heights]
    Heights --> Bilinear[Interpolate 9x9 outer grid]
    Bilinear --> Available[TerrainGroundSample available]
    Cache -->|missing/invalid| Unavailable[TerrainGroundSample unavailable]
 ```
 ## Lifecycle/state
 ```mermaid
 stateDiagram-v2
    [*] --> TileUnknown
    TileUnknown --> TileAvailable: first query / successful load
    TileUnknown --> TileUnavailable: first query / missing or failed
    TileAvailable --> TileAvailable: cached queries
    TileUnavailable --> TileUnavailable: cached queries
    TileAvailable --> [*]: query released
    TileUnavailable --> [*]: query released
 ```
 Unavailable tiles are cached intentionally to avoid repeated filesystem/native
 work each physics tick. Recovery after files appear requires replacing the query
 instance; hot-reload invalidation is outside this M02 package.
 ## Main sequence
 ```mermaid
 sequenceDiagram
    participant Player as ThirdPersonWowController
    participant Query as TerrainQuery
    participant ADT as AdtTerrainQuery
    participant Mapper as CoordinateMapper
    participant Native as ADTLoader
    Player->>Query: sample_ground_height(GodotWorldPosition)
    Query->>ADT: implementation dispatch
    ADT->>Mapper: tile/local/chunk coordinates
    alt tile not cached
        ADT->>Native: load_adt(absolute path)
        Native-->>ADT: ADT Dictionary
    end
    ADT->>ADT: select chunk and interpolate heights
    ADT-->>Player: TerrainGroundSample
    Player->>Player: apply existing offset/snap if available
 ```
 ## Ownership, threading and resources
 - Player scene owns the active `TerrainQuery` reference.
 - `AdtTerrainQuery` exclusively owns tile/failure dictionaries until released.
 - Current production calls and cache mutations occur on the main physics thread.
 - Native loader result dictionaries do not cross the adapter boundary.
 - Samples and typed positions are immutable caller-held values.
 - The module creates no Nodes, Resources, RIDs or background jobs.
 - Future worker-backed queries require an explicit async/result contract rather
  than concurrent mutation of the current dictionaries.
 ## Errors, cancellation and recovery
 | Failure | Detection | Behavior | Diagnostic | Recovery |
 |---|---|---|---|---|
 | Base contract used directly | Base method | Unavailable sample | `terrain_query_not_implemented` | Inject implementation |
 | Native loader absent | ClassDB check | Cache unavailable tile | `adt_loader_unavailable` | Load extension and replace query |
 | ADT file absent | File check | Cache unavailable tile | `adt_source_missing` | Restore corpus and replace query |
 | Native parse empty/fails | Result validation | Cache unavailable tile | `adt_load_failed` | Inspect source/parser; replace query |
 | Injected loader returns wrong type | Type check | Cache unavailable tile | `adt_loader_result_invalid` | Fix adapter |
 | Chunk absent | Chunk lookup | Unavailable sample | `adt_chunk_missing` | Validate ADT dictionary |
 | Height array shorter than 145 | Size check | Unavailable sample | `adt_chunk_heights_invalid` | Fix parser/source |
 | Non-finite interpolated height | Sample invariant | Unavailable sample | `terrain_height_not_finite` | Inspect source values |
 | Null query injection | Scene guard | Existing query retained | Player composition error | Pass valid query |
 There are no asynchronous operations to cancel. Replacing/releasing the query
 is the deterministic cache-reset and recovery path.
 ## Configuration and capabilities
 | Setting/capability | Default | Profile | Runtime mutable | Effect |
 |---|---|---|---|---|
 | Extracted directory | Player `extracted_dir` | Current sandbox | Captured at creation | ADT source root |
 | Map directory name | Player `map_name` | Current sandbox | Captured at creation | ADT filename/path |
 | Loader override | Invalid callable | Test/custom data source | Constructor only | Bypasses production ClassDB/file loading |
 | Tile cache | Enabled | All current uses | Cleared by replacing query | Avoids repeated parse/failure work |
 | Height policy | 9x9 outer-grid bilinear | Current sandbox | Fixed | Preserves pre-extraction behavior |
 ## Persistence, cache and migration
 The cache is in-memory and unversioned because it holds native loader output for
 one query lifetime. No disk cache, schema or migration changes are introduced.
 Existing ADT/native/cache format versions remain unchanged.
 ## Diagnostics and observability
 - Logs: dedicated verifier emits `TERRAIN_QUERY PASS` or named failures.
 - Structured status: every unavailable sample has a stable `failure_code`.
 - Metrics: synthetic verifier counts loader calls to prove one load per tile.
 - Debug views: none.
 - Correlation IDs: not applicable to synchronous local query.
 ## Verification
 - Contract: available/unavailable/base/non-finite result invariants.
 - Pure synthetic adapter: typed coordinate mapping, exact chunk selection,
  145-height layout and bilinear interpolation within `0.002` units (Vector3
  source precision), plus cached second query.
 - Failures: empty tile and invalid height array produce stable codes.
 - Integration: asset-free player scene accepts injected flat query and preserves
  spawn offset `0.05` plus physics ground snap.
 - Boundary: source regression rejects ADT loader/cache/chunk helpers in player.
 - Fidelity evidence: existing interpolation and snap behavior only; no
  original-client or collision parity claim.
 - Performance budget: one dictionary cache lookup and scalar interpolation per
  cached query; native parse only on first tile access.
 ## Extension points
 - Streaming renderer or physics backend may implement `TerrainQuery` without changing player/movement.
 - Future result may grow separate slope, surface, liquid or collision contracts;
  incompatible additions require a versioned contract rather than Dictionary fields.
 - Test/authoring data sources may use constructor loader override.
 - Async streaming requires a separate availability/update model.
 ## Capability status
 | Capability | Status | Evidence | Gap/next step |
 |---|---|---|---|
 | Typed replaceable ground-height query | Implemented | Contract and injected player regression | Integrate target checklist after review |
 | Existing ADT height interpolation | Implemented | Synthetic fractional-grid fixture | Compare terrain contact with build 12340 |
 | Per-tile success/failure cache | Implemented | Loader call-count regression | Add explicit invalidation only with authoring/hot reload |
 | Renderer/streaming cache backend | Planned | Boundary permits replacement | M03 renderer facade/public terrain backend |
 | Holes/slopes/collision | Planned | Outside height-only contract | Later movement/physics package |
 | Liquid/swim query | Planned | Outside contract | M09/M12 world gameplay |
 ## Known gaps and risks
 - Bilinear outer-grid height is the inherited sandbox approximation; exact ADT
  triangle choice, holes and collision are not represented.
 - Query is synchronous; first access may parse an ADT on the main thread exactly
  as before extraction. A streaming/backend replacement is future work.
 - Unavailable results remain cached until query replacement.
 - Player still owns ground offset/snap policy; only data access is extracted.
 - Existing native dictionaries remain dynamic inside the adapter.
 ## Source map
 | Path | Responsibility |
 |---|---|
 | `src/gameplay/terrain/terrain_ground_sample.gd` | Immutable available/unavailable result |
 | `src/gameplay/terrain/terrain_query.gd` | Replaceable typed query boundary |
 | `src/gameplay/terrain/adt_terrain_query.gd` | Native ADT adapter, cache, chunk selection and interpolation |
 | `src/scenes/player/third_person_wow_controller.gd` | Query composition and existing ground-snap consumer |
 | `src/tools/verify_terrain_query.gd` | Synthetic contract/cache/failure/injection regression |
 | `src/tests/scenes/player_input_regression.tscn` | Asset-free player composition fixture |
 ## Related decisions and references
 - ADR: none; no coordinate, format or authority decision changed.
 - Upstream/reference: `targets/02-player-decomposition.md`,
  `targets/roadmap/02-rendering-and-graphics.md`,
  `targets/roadmap/04-gameplay-systems.md`, `docs/ARCHITECTURE.md`.
@@ -0,0 +1,166 @@
 class_name AdtTerrainQuery
 extends TerrainQuery
 ## TerrainQuery adapter for existing native ADT dictionaries.
 ## Parsed tiles, including unavailable results, are cached for this query's
 ## lifetime. The adapter is main-thread owned and creates no scene resources.
 const COORDINATE_MAPPER_SCRIPT := preload("res://src/domain/coordinates/coordinate_mapper.gd")
 const CHUNK_SIZE_UNITS := COORDINATE_MAPPER_SCRIPT.ADT_CHUNK_SIZE_YARDS
 const OUTER_GRID_UNIT_SIZE := CHUNK_SIZE_UNITS / 8.0
 var _extracted_directory: String
 var _map_directory_name: String
 var _adt_tile_loader_override: Callable
 var _adt_tile_cache: Dictionary = {}
 var _failure_code_by_tile_key: Dictionary = {}
 ## Creates an ADT query for one map. `adt_tile_loader_override` is an optional
 ## test/data-source seam receiving the absolute ADT path and returning a Dictionary.
 func _init(
 		extracted_directory: String,
 		map_directory_name: String,
 		adt_tile_loader_override: Callable = Callable()
 ) -> void:
 	_extracted_directory = extracted_directory
 	_map_directory_name = map_directory_name
 	_adt_tile_loader_override = adt_tile_loader_override
 ## Samples the existing 9x9 outer-height grid with bilinear interpolation.
 func sample_ground_height(godot_world_position: GodotWorldPosition) -> TerrainGroundSample:
 	var tile_coordinate = COORDINATE_MAPPER_SCRIPT.godot_to_adt_tile(godot_world_position)
 	var tile_local_position = COORDINATE_MAPPER_SCRIPT.godot_to_adt_tile_local(godot_world_position)
 	var chunk_coordinate = COORDINATE_MAPPER_SCRIPT.adt_tile_local_to_chunk(
 		tile_coordinate,
 		tile_local_position
 	)
 	var tile_key := _tile_key(tile_coordinate.tile_x, tile_coordinate.tile_y)
 	var adt_tile_data := _load_adt_tile(tile_coordinate.tile_x, tile_coordinate.tile_y)
 	if adt_tile_data.is_empty():
 		return TerrainGroundSample.unavailable(
 			_failure_code_by_tile_key.get(tile_key, &"adt_tile_unavailable")
 		)
 	var tile_origin := _find_tile_origin(adt_tile_data)
 	var chunk := _find_chunk(
 		adt_tile_data,
 		clampi(chunk_coordinate.chunk_x, 0, 15),
 		clampi(chunk_coordinate.chunk_y, 0, 15),
 		tile_origin
 	)
 	if chunk.is_empty():
 		return TerrainGroundSample.unavailable(&"adt_chunk_missing")
 	var heights: PackedFloat32Array = chunk.get("heights", PackedFloat32Array())
 	if heights.size() < 145:
 		return TerrainGroundSample.unavailable(&"adt_chunk_heights_invalid")
 	var chunk_origin: Vector3 = chunk.get("origin", Vector3.ZERO)
 	var chunk_local_x := godot_world_position.x_units - chunk_origin.x
 	var chunk_local_z := godot_world_position.z_units - chunk_origin.z
 	var grid_x := clampf(chunk_local_x / OUTER_GRID_UNIT_SIZE, 0.0, 8.0)
 	var grid_z := clampf(chunk_local_z / OUTER_GRID_UNIT_SIZE, 0.0, 8.0)
 	var x0 := clampi(int(floor(grid_x)), 0, 8)
 	var z0 := clampi(int(floor(grid_z)), 0, 8)
 	var x1 := mini(x0 + 1, 8)
 	var z1 := mini(z0 + 1, 8)
 	var fraction_x := grid_x - float(x0)
 	var fraction_z := grid_z - float(z0)
 	var height_x0 := lerpf(
 		heights[_outer_height_index(z0, x0)],
 		heights[_outer_height_index(z0, x1)],
 		fraction_x
 	)
 	var height_x1 := lerpf(
 		heights[_outer_height_index(z1, x0)],
 		heights[_outer_height_index(z1, x1)],
 		fraction_x
 	)
 	return TerrainGroundSample.available(
 		chunk_origin.y + lerpf(height_x0, height_x1, fraction_z)
 	)
 func _load_adt_tile(tile_x: int, tile_y: int) -> Dictionary:
 	var tile_key := _tile_key(tile_x, tile_y)
 	if _adt_tile_cache.has(tile_key):
 		return _adt_tile_cache[tile_key]
 	var resource_path := _extracted_directory.path_join(
 		"World/Maps/%s/%s_%d_%d.adt" % [_map_directory_name, _map_directory_name, tile_x, tile_y]
 	)
 	var absolute_path := ProjectSettings.globalize_path(resource_path)
 	var adt_tile_data: Dictionary = {}
 	var failure_code: StringName = &""
 	if _adt_tile_loader_override.is_valid():
 		var override_result = _adt_tile_loader_override.call(absolute_path)
 		if override_result is Dictionary:
 			adt_tile_data = override_result
 		else:
 			failure_code = &"adt_loader_result_invalid"
 	elif not ClassDB.class_exists("ADTLoader"):
 		failure_code = &"adt_loader_unavailable"
 	elif not FileAccess.file_exists(absolute_path):
 		failure_code = &"adt_source_missing"
 	else:
 		var loader = ClassDB.instantiate("ADTLoader")
 		if loader != null:
 			var load_result = loader.call("load_adt", absolute_path)
 			if load_result is Dictionary:
 				adt_tile_data = load_result
 		if adt_tile_data.is_empty():
 			failure_code = &"adt_load_failed"
 	if adt_tile_data.is_empty() and failure_code.is_empty():
 		failure_code = &"adt_tile_unavailable"
 	_adt_tile_cache[tile_key] = adt_tile_data
 	_failure_code_by_tile_key[tile_key] = failure_code
 	return adt_tile_data
 func _find_chunk(
 		adt_tile_data: Dictionary,
 		chunk_x: int,
 		chunk_y: int,
 		tile_origin: Vector3
 ) -> Dictionary:
 	for chunk in adt_tile_data.get("chunks", []) as Array:
 		if chunk.is_empty():
 			continue
 		var chunk_origin: Vector3 = chunk.get("origin", Vector3.ZERO)
 		var local_origin := chunk_origin - tile_origin
 		var candidate_chunk_x := clampi(int(round(local_origin.x / CHUNK_SIZE_UNITS)), 0, 15)
 		var candidate_chunk_y := clampi(int(round(local_origin.z / CHUNK_SIZE_UNITS)), 0, 15)
 		if candidate_chunk_x == chunk_x and candidate_chunk_y == chunk_y:
 			return chunk
 	return {}
 func _find_tile_origin(adt_tile_data: Dictionary) -> Vector3:
 	var has_origin := false
 	var minimum_x := 0.0
 	var minimum_z := 0.0
 	for chunk in adt_tile_data.get("chunks", []) as Array:
 		if chunk.is_empty():
 			continue
 		var chunk_origin: Vector3 = chunk.get("origin", Vector3.ZERO)
 		if not has_origin:
 			minimum_x = chunk_origin.x
 			minimum_z = chunk_origin.z
 			has_origin = true
 		else:
 			minimum_x = minf(minimum_x, chunk_origin.x)
 			minimum_z = minf(minimum_z, chunk_origin.z)
 	return Vector3(minimum_x, 0.0, minimum_z) if has_origin else Vector3.ZERO
 func _tile_key(tile_x: int, tile_y: int) -> String:
 	return "%d_%d" % [tile_x, tile_y]
 func _outer_height_index(row: int, column: int) -> int:
 	return row * 17 + column
@@ -0,0 +1 @@
 uid://cq7scvxqw6ffm
@@ -0,0 +1,49 @@
 class_name TerrainGroundSample
 extends RefCounted
 ## Immutable result of a terrain ground-height query in Godot world units.
 ## An unavailable sample carries a stable failure code instead of overloading a
 ## numeric height with `NAN` at the public boundary.
 var is_available: bool:
 	get:
 		return _is_available
 var height_units: float:
 	get:
 		return _height_units
 var failure_code: StringName:
 	get:
 		return _failure_code
 var _is_available: bool
 var _height_units: float
 var _failure_code: StringName
 ## Creates an available ground sample in Godot world units.
 static func available(height_units_value: float) -> TerrainGroundSample:
 	return TerrainGroundSample.new(true, height_units_value, &"")
 ## Creates an unavailable sample with a stable diagnostic code.
 static func unavailable(failure_code_value: StringName) -> TerrainGroundSample:
 	return TerrainGroundSample.new(false, 0.0, failure_code_value)
 ## Normalizes factory inputs so available samples are finite and unavailable
 ## samples always carry a non-empty failure code.
 func _init(
 		is_available_value: bool,
 		height_units_value: float,
 		failure_code_value: StringName
 ) -> void:
 	_is_available = is_available_value and is_finite(height_units_value)
 	_height_units = height_units_value if _is_available else 0.0
 	if _is_available:
 		_failure_code = &""
 	elif not is_finite(height_units_value):
 		_failure_code = &"terrain_height_not_finite"
 	else:
 		_failure_code = failure_code_value if not failure_code_value.is_empty() else &"terrain_unavailable"
@@ -0,0 +1 @@
 uid://boe5qkip6ffku
@@ -0,0 +1,12 @@
 class_name TerrainQuery
 extends RefCounted
 ## Replaceable scene-free boundary for gameplay terrain height sampling.
 ## Implementations receive a typed Godot world position and must return an
 ## explicit available/unavailable result without mutating the caller.
 ## Samples terrain ground height at a typed Godot world position.
 ## The base implementation reports `terrain_query_not_implemented`.
 func sample_ground_height(_godot_world_position: GodotWorldPosition) -> TerrainGroundSample:
 	return TerrainGroundSample.unavailable(&"terrain_query_not_implemented")
@@ -0,0 +1 @@
 uid://d3f2hetuo342q
@@ -10,9 +10,7 @@ const ADT_TILE_LOCAL_POSITION_SCRIPT := preload("res://src/domain/coordinates/ad
 const PLAYER_INPUT_SOURCE_SCRIPT := preload("res://src/gameplay/input/player_input_source.gd")
 const PLAYER_INPUT_ACTIONS_SCRIPT := preload("res://src/gameplay/input/player_input_actions.gd")
 const LOCAL_PLAYER_MOVEMENT_CONTROLLER_SCRIPT := preload("res://src/gameplay/movement/local_player_movement_controller.gd")
-
+const ADT_TERRAIN_QUERY_SCRIPT := preload("res://src/gameplay/terrain/adt_terrain_query.gd")
 const CHUNK_SIZE := COORDINATE_MAPPER_SCRIPT.ADT_CHUNK_SIZE_YARDS
 const UNIT_SIZE := CHUNK_SIZE / 8.0
@export var extracted_dir: String = "res://data/extracted"
@export var map_name: String = "Azeroth"
@@ -55,13 +53,24 @@ var _active_animation := ""
 var _captured := false
 var _yaw := 0.0
 var _pitch := deg_to_rad(-18.0)
 var _adt_cache: Dictionary = {}
 var _player_input_source: PlayerInputSource
 var _local_movement_controller: LocalPlayerMovementController
 var _terrain_query: TerrainQuery
 ## Replaces the ground-height backend without changing player movement or presentation.
 ## Passing null is a composition error and leaves the current query unchanged.
 func set_terrain_query(terrain_query: TerrainQuery) -> void:
 	if terrain_query == null:
 		push_error("ThirdPersonWowController: terrain query cannot be null")
 		return
 	_terrain_query = terrain_query
 func _ready() -> void:
 	_player_input_source = PLAYER_INPUT_SOURCE_SCRIPT.new()
 	if _terrain_query == null:
 		_terrain_query = ADT_TERRAIN_QUERY_SCRIPT.new(extracted_dir, map_name)
 	_local_movement_controller = LOCAL_PLAYER_MOVEMENT_CONTROLLER_SCRIPT.new(
 		run_speed,
 		backward_speed,
@@ -83,9 +92,9 @@ func _ready() -> void:
 		var spawn_position = COORDINATE_MAPPER_SCRIPT.adt_tile_local_to_godot(spawn_tile, spawn_local)
 		global_position = Vector3(spawn_position.x_units, spawn_position.y_units, spawn_position.z_units)
 	_load_character_visual()
-	var ground := _sample_ground_height(global_position)
+	var spawn_ground_sample := _sample_ground_height(global_position)
-	if is_finite(ground):
+	if spawn_ground_sample.is_available:
-		global_position.y = ground + ground_offset
+		global_position.y = spawn_ground_sample.height_units + ground_offset
 	_yaw = rotation.y
 	_apply_camera_transform()
@@ -124,9 +133,9 @@ func _physics_process(delta: float) -> void:
 	global_position += _local_movement_controller.advance(move_intent, godot_world_movement_basis, delta)
 	if not _local_movement_controller.is_flight_enabled:
-		var ground := _sample_ground_height(global_position)
+		var ground_sample := _sample_ground_height(global_position)
-		if is_finite(ground):
+		if ground_sample.is_available:
-			var target_y := ground + ground_offset
+			var target_y := ground_sample.height_units + ground_offset
 			global_position.y = lerpf(global_position.y, target_y, clampf(ground_snap_speed * delta, 0.0, 1.0))
 	var movement_velocity := _local_movement_controller.godot_world_velocity_units_per_second
@@ -298,95 +307,11 @@ func _apply_camera_transform() -> void:
 		_camera.rotation = Vector3.ZERO
-func _sample_ground_height(world_pos: Vector3) -> float:
+func _sample_ground_height(godot_world_position: Vector3) -> TerrainGroundSample:
-	var typed_world_position = GODOT_WORLD_POSITION_SCRIPT.new(world_pos.x, world_pos.y, world_pos.z)
+	return _terrain_query.sample_ground_height(
-	var tile_coordinate = COORDINATE_MAPPER_SCRIPT.godot_to_adt_tile(typed_world_position)
+		GODOT_WORLD_POSITION_SCRIPT.new(
-	var tile_local_position = COORDINATE_MAPPER_SCRIPT.godot_to_adt_tile_local(typed_world_position)
+			godot_world_position.x,
-	var chunk_coordinate = COORDINATE_MAPPER_SCRIPT.adt_tile_local_to_chunk(tile_coordinate, tile_local_position)
+			godot_world_position.y,
-	var data := _load_adt(tile_coordinate.tile_x, tile_coordinate.tile_y)
+			godot_world_position.z
-	if data.is_empty():
+		)
-		return NAN
+	)
 	var tile_origin := _get_tile_origin(data)
 	var chunk_x := clampi(chunk_coordinate.chunk_x, 0, 15)
 	var chunk_y := clampi(chunk_coordinate.chunk_y, 0, 15)
 	var chunk := _find_chunk(data, chunk_x, chunk_y, tile_origin)
 	if chunk.is_empty():
 		return NAN
 	var origin: Vector3 = chunk.get("origin", Vector3.ZERO)
 	var chunk_local := world_pos - origin
 	var gx := clampf(chunk_local.x / UNIT_SIZE, 0.0, 8.0)
 	var gz := clampf(chunk_local.z / UNIT_SIZE, 0.0, 8.0)
 	var x0 := clampi(int(floor(gx)), 0, 8)
 	var z0 := clampi(int(floor(gz)), 0, 8)
 	var x1 := mini(x0 + 1, 8)
 	var z1 := mini(z0 + 1, 8)
 	var fx := gx - float(x0)
 	var fz := gz - float(z0)
 	var heights: PackedFloat32Array = chunk.get("heights", PackedFloat32Array())
 	if heights.size() < 145:
 		return NAN
 	var h00 := heights[_outer(z0, x0)]
 	var h10 := heights[_outer(z0, x1)]
 	var h01 := heights[_outer(z1, x0)]
 	var h11 := heights[_outer(z1, x1)]
 	var hx0 := lerpf(h00, h10, fx)
 	var hx1 := lerpf(h01, h11, fx)
 	return origin.y + lerpf(hx0, hx1, fz)
 func _load_adt(tx: int, ty: int) -> Dictionary:
 	var key := "%d_%d" % [tx, ty]
 	if _adt_cache.has(key):
 		return _adt_cache[key]
 	if not ClassDB.class_exists("ADTLoader"):
 		_adt_cache[key] = {}
 		return {}
 	var res_path := extracted_dir.path_join("World/Maps/%s/%s_%d_%d.adt" % [map_name, map_name, tx, ty])
 	var abs_path := ProjectSettings.globalize_path(res_path)
 	if not FileAccess.file_exists(abs_path):
 		_adt_cache[key] = {}
 		return {}
 	var loader = ClassDB.instantiate("ADTLoader")
 	var data: Dictionary = loader.call("load_adt", abs_path) if loader else {}
 	_adt_cache[key] = data
 	return data
 func _find_chunk(data: Dictionary, chunk_x: int, chunk_y: int, tile_origin: Vector3) -> Dictionary:
 	for chunk in data.get("chunks", []) as Array:
 		if chunk.is_empty():
 			continue
 		var origin: Vector3 = chunk.get("origin", Vector3.ZERO)
 		var local := origin - tile_origin
 		var cx := clampi(int(round(local.x / CHUNK_SIZE)), 0, 15)
 		var cy := clampi(int(round(local.z / CHUNK_SIZE)), 0, 15)
 		if cx == chunk_x and cy == chunk_y:
 			return chunk
 	return {}
 func _get_tile_origin(data: Dictionary) -> Vector3:
 	var found := false
 	var min_x := 0.0
 	var min_z := 0.0
 	for chunk in data.get("chunks", []) as Array:
 		if chunk.is_empty():
 			continue
 		var origin: Vector3 = chunk.get("origin", Vector3.ZERO)
 		if not found:
 			min_x = origin.x
 			min_z = origin.z
 			found = true
 		else:
 			min_x = minf(min_x, origin.x)
 			min_z = minf(min_z, origin.z)
 	return Vector3(min_x, 0.0, min_z) if found else Vector3.ZERO
 func _outer(row: int, col: int) -> int:
 	return row * 17 + col
@@ -20,7 +20,8 @@ const ALLOWED_LEGACY_NAME_PATHS: Array[String] = [
 const REQUIRED_MAPPER_CALLS := {
 	"res://src/scenes/sky/wow_sky_controller.gd": ["godot_to_canonical", "godot_to_adt_tile", "godot_to_adt_tile_local"],
 	"res://src/scenes/streaming/streaming_world_loader.gd": ["godot_to_adt_tile", "godot_to_adt_tile_local", "adt_tile_local_to_godot"],
-	"res://src/scenes/player/third_person_wow_controller.gd": ["godot_to_adt_tile", "adt_tile_local_to_godot"],
+	"res://src/scenes/player/third_person_wow_controller.gd": ["adt_tile_local_to_godot"],
 	"res://src/gameplay/terrain/adt_terrain_query.gd": ["godot_to_adt_tile", "godot_to_adt_tile_local", "adt_tile_local_to_chunk"],
 	"res://src/tools/probe_render_terrain_height.gd": ["godot_to_adt_tile"],
 }
@@ -59,7 +60,7 @@ func _initialize() -> void:
 		quit(1)
 		return
-	print("COORDINATE_CONVERSION_BOUNDARIES PASS files=%d native_boundary=1 oracle=1 consumers=4 classifier_cases=6" % source_paths.size())
+	print("COORDINATE_CONVERSION_BOUNDARIES PASS files=%d native_boundary=1 oracle=1 consumers=5 classifier_cases=6" % source_paths.size())
 	quit(0)
@@ -0,0 +1,198 @@
 extends SceneTree
 ## Headless M02 contract, interpolation, cache and player-injection regression.
 const TERRAIN_QUERY_PATH := "res://src/gameplay/terrain/terrain_query.gd"
 const ADT_TERRAIN_QUERY_PATH := "res://src/gameplay/terrain/adt_terrain_query.gd"
 const PLAYER_CONTROLLER_PATH := "res://src/scenes/player/third_person_wow_controller.gd"
 const REGRESSION_SCENE_PATH := "res://src/tests/scenes/player_input_regression.tscn"
 var _synthetic_adt_tile_data: Dictionary = {}
 var _synthetic_loader_call_count := 0
 class FlatTerrainQuery extends TerrainQuery:
 	var _height_units: float
 	func _init(height_units: float) -> void:
 		_height_units = height_units
 	func sample_ground_height(_godot_world_position: GodotWorldPosition) -> TerrainGroundSample:
 		return TerrainGroundSample.available(_height_units)
 func _initialize() -> void:
 	_run_verification.call_deferred()
 func _run_verification() -> void:
 	var failures: Array[String] = []
 	_verify_typed_result_contract(failures)
 	_verify_synthetic_adt_interpolation_and_cache(failures)
 	_verify_unavailable_tile(failures)
 	_verify_player_injection(failures)
 	_verify_source_boundaries(failures)
 	if not failures.is_empty():
 		for failure in failures:
 			push_error("TERRAIN_QUERY: %s" % failure)
 		quit(1)
 		return
 	print("TERRAIN_QUERY PASS contract=4 interpolation=1 cache=1 failures=2 player_injection=1")
 	quit(0)
 func _verify_typed_result_contract(failures: Array[String]) -> void:
 	var available_sample := TerrainGroundSample.available(123.5)
 	_expect_true(available_sample.is_available, "available sample state", failures)
 	_expect_near(available_sample.height_units, 123.5, "available sample height", failures)
 	_expect_true(available_sample.failure_code.is_empty(), "available sample has no failure", failures)
 	var unavailable_sample := TerrainGroundSample.unavailable(&"synthetic_failure")
 	_expect_true(not unavailable_sample.is_available, "unavailable sample state", failures)
 	_expect_equal(unavailable_sample.failure_code, &"synthetic_failure", "unavailable failure code", failures)
 	var base_sample := TerrainQuery.new().sample_ground_height(GodotWorldPosition.new(0.0, 0.0, 0.0))
 	_expect_equal(base_sample.failure_code, &"terrain_query_not_implemented", "base query failure", failures)
 	var non_finite_sample := TerrainGroundSample.available(NAN)
 	_expect_true(not non_finite_sample.is_available, "non-finite sample unavailable", failures)
 	_expect_equal(non_finite_sample.failure_code, &"terrain_height_not_finite", "non-finite failure code", failures)
 func _verify_synthetic_adt_interpolation_and_cache(failures: Array[String]) -> void:
 	var query_position := GodotWorldPosition.new(17000.0, 999.0, 26525.0)
 	_synthetic_adt_tile_data = _build_synthetic_adt_tile(query_position)
 	_synthetic_loader_call_count = 0
 	var terrain_query := AdtTerrainQuery.new("res://synthetic", "Azeroth", _load_synthetic_adt_tile)
 	var first_sample := terrain_query.sample_ground_height(query_position)
 	_expect_true(first_sample.is_available, "synthetic ADT sample available", failures)
 	_expect_near_with_tolerance(first_sample.height_units, 137.0, 0.002, "synthetic bilinear height", failures)
 	var second_sample := terrain_query.sample_ground_height(query_position)
 	_expect_near_with_tolerance(second_sample.height_units, 137.0, 0.002, "cached synthetic height", failures)
 	_expect_equal(_synthetic_loader_call_count, 1, "ADT tile loaded once", failures)
 func _verify_unavailable_tile(failures: Array[String]) -> void:
 	var query_position := GodotWorldPosition.new(17000.0, 0.0, 26525.0)
 	var empty_query := AdtTerrainQuery.new("res://synthetic", "Azeroth", func(_path: String) -> Dictionary: return {})
 	var empty_sample := empty_query.sample_ground_height(query_position)
 	_expect_true(not empty_sample.is_available, "empty ADT unavailable", failures)
 	_expect_equal(empty_sample.failure_code, &"adt_tile_unavailable", "empty ADT failure", failures)
 	var invalid_heights_data := _build_synthetic_adt_tile(query_position)
 	var invalid_chunks: Array = invalid_heights_data.get("chunks", [])
 	(invalid_chunks[invalid_chunks.size() - 1] as Dictionary)["heights"] = PackedFloat32Array()
 	var invalid_query := AdtTerrainQuery.new(
 		"res://synthetic",
 		"Azeroth",
 		func(_path: String) -> Dictionary: return invalid_heights_data
 	)
 	var invalid_sample := invalid_query.sample_ground_height(query_position)
 	_expect_equal(invalid_sample.failure_code, &"adt_chunk_heights_invalid", "invalid heights failure", failures)
 func _verify_player_injection(failures: Array[String]) -> void:
 	var packed_scene := load(REGRESSION_SCENE_PATH) as PackedScene
 	_expect_true(packed_scene != null, "regression scene loads", failures)
 	if packed_scene == null:
 		return
 	var player := packed_scene.instantiate() as CharacterBody3D
 	player.set_terrain_query(FlatTerrainQuery.new(20.0))
 	root.add_child(player)
 	player.set_physics_process(false)
 	_expect_near(player.position.y, 20.05, "injected spawn ground height", failures)
 	player.position.y = 30.0
 	player.call("_physics_process", 1.0)
 	_expect_near(player.position.y, 20.05, "injected physics ground snap", failures)
 	player.free()
 func _verify_source_boundaries(failures: Array[String]) -> void:
 	var terrain_contract_source := _read_text(TERRAIN_QUERY_PATH, failures)
 	_expect_true(not terrain_contract_source.contains("extends Node"), "TerrainQuery omits Node", failures)
 	_expect_true(not terrain_contract_source.contains("Vector3"), "TerrainQuery omits untyped Vector3 position", failures)
 	var adt_query_source := _read_text(ADT_TERRAIN_QUERY_PATH, failures)
 	_expect_true(adt_query_source.contains("ADTLoader"), "ADT adapter owns native loader", failures)
 	_expect_true(adt_query_source.contains("_adt_tile_cache"), "ADT adapter owns tile cache", failures)
 	var player_source := _read_text(PLAYER_CONTROLLER_PATH, failures)
 	for forbidden_text in ["ADTLoader", "load_adt", "_adt_cache", "_find_chunk", "_outer_height_index"]:
 		_expect_true(not player_source.contains(forbidden_text), "player omits %s" % forbidden_text, failures)
 	_expect_true(player_source.contains("set_terrain_query"), "player exposes terrain query injection", failures)
 	_expect_true(player_source.contains("_terrain_query.sample_ground_height"), "player delegates ground sampling", failures)
 func _build_synthetic_adt_tile(query_position: GodotWorldPosition) -> Dictionary:
 	var tile_coordinate := CoordinateMapper.godot_to_adt_tile(query_position)
 	var tile_local_position := CoordinateMapper.godot_to_adt_tile_local(query_position)
 	var chunk_coordinate := CoordinateMapper.adt_tile_local_to_chunk(tile_coordinate, tile_local_position)
 	var chunk_size := CoordinateMapper.ADT_CHUNK_SIZE_YARDS
 	var outer_grid_unit_size := chunk_size / 8.0
 	var target_chunk_origin := Vector3(
 		query_position.x_units - outer_grid_unit_size * 4.5,
 		100.0,
 		query_position.z_units - outer_grid_unit_size * 3.25
 	)
 	var tile_origin := target_chunk_origin - Vector3(
 		chunk_coordinate.chunk_x * chunk_size,
 		0.0,
 		chunk_coordinate.chunk_y * chunk_size
 	)
 	var heights := PackedFloat32Array()
 	heights.resize(145)
 	for row in range(9):
 		for column in range(9):
 			heights[row * 17 + column] = float(row * 10 + column)
 	var target_chunk := {"origin": target_chunk_origin, "heights": heights}
 	if chunk_coordinate.chunk_x == 0 and chunk_coordinate.chunk_y == 0:
 		return {"chunks": [target_chunk]}
 	return {
 		"chunks": [
 			{"origin": tile_origin, "heights": PackedFloat32Array()},
 			target_chunk,
 		]
 	}
 func _load_synthetic_adt_tile(_absolute_path: String) -> Dictionary:
 	_synthetic_loader_call_count += 1
 	return _synthetic_adt_tile_data
 func _read_text(path: String, failures: Array[String]) -> String:
 	var file := FileAccess.open(path, FileAccess.READ)
 	if file == null:
 		failures.append("cannot open %s" % path)
 		return ""
 	return file.get_as_text()
 func _expect_near(actual_value: float, expected_value: float, label: String, failures: Array[String]) -> void:
 	if absf(actual_value - expected_value) > 0.000001:
 		failures.append("%s expected %.6f, got %.6f" % [label, expected_value, actual_value])
 func _expect_near_with_tolerance(
 		actual_value: float,
 		expected_value: float,
 		tolerance: float,
 		label: String,
 		failures: Array[String]
 ) -> void:
 	if absf(actual_value - expected_value) > tolerance:
 		failures.append("%s expected %.6f ± %.6f, got %.6f" % [label, expected_value, tolerance, actual_value])
 func _expect_equal(actual_value: Variant, expected_value: Variant, label: String, failures: Array[String]) -> void:
 	if actual_value != expected_value:
 		failures.append("%s expected %s, got %s" % [label, expected_value, actual_value])
 func _expect_true(actual_value: bool, label: String, failures: Array[String]) -> void:
 	if not actual_value:
 		failures.append("%s expected true" % label)