Files
settled-reach/client/scripts/protocol/step_canvas_protocol.gd
T
jpmschweitzerandClaude Fable 5 d28d24fd26 feat(ui): step-canvas map component — RTT terrain + stepped zoom (D-255, T-1182)
The two-layer client rebuild per D-255(a)(b)(e), replacing the
_canvas.scale continuous-zoom model with one viewer, one path, all six
rungs:

- step_canvas_protocol.gd: StepCanvasRequest/Response codec against
  the T-1181 wire contract — incl. the discovered png_bytes subtlety
  (rmp_serde without serde_bytes emits a msgpack int-array, not bin;
  decode repacks via PackedByteArray before load_png_from_buffer) and
  the extent-echo rule (read the server-clamped extent, never assume
  the requested one).
- step_canvas/ component: transport (six-rung ladder, cursor-anchored
  scroll steps, edge-scroll/WASD pan with re-request on edge crossing,
  hard reset-to-Global), RTT terrain layer (Image.set_pixel colorize
  per the c1 measured ruling, texture.update reuse on step-cross,
  NEAREST coarse / LINEAR fine per rung), unscaled screen-space
  annotation sibling (courses + settlement markers at literal px),
  in-memory LRU cache (Tier 1; T-1183 layers the disk tiers beneath),
  request lifecycle (pending retry, staleness gate, extent echo).
- Full _canvas.scale retirement in the same change: the zoom-scaled
  canvas model, the _zs compensation family, select_rung /
  MAX_COVERAGE_M / compute_tile_grid, the orbital-mosaic-vs-window
  two-path split, _view_zoom/_canonical_fit_zoom — 10 source files
  deleted; their 14 test suites deleted with them (T-1157 dead-goldens
  rule; replacement visual-capture coverage is re-scoped T-1157).
- Surviving surfaces kept per the ticket: atlas_window_cache.gd's LRU
  shape (the ticket's named file atlas_window_tile_set.gd was the
  retiring orchestrator; the real LRU shape lives in
  atlas_window_cache.gd — cited in step_canvas_cache.gd), overlay
  colors, legend/overlay-bar chrome, AtlasViewer descend geometry.

Determinism boundary per D-255(e): the client interpolates only within
the closed server-supplied input set. 7 new gdUnit suites (164 cases)
incl. a real extent-echo bug caught by its own test during
implementation. Full client suite green (exit 0) with the live-gated
suites running against a worktree server build.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
2026-07-25 08:53:48 +02:00

178 lines
8.7 KiB
GDScript

class_name StepCanvasProtocol
## StepCanvasRequest/StepCanvasResponse wire codec (T-1182, D-255(c)) — the
## stepped Atlas ladder's tagged-envelope carrier, executing the D-225
## migration server/src/atlas/step_canvas.rs already ships (T-1181, PR #201).
## Split out of protocol.gd (not folded in), same rationale as
## browse_protocol.gd/atlas_map_protocol.gd — stay under gdlint's
## max-file-lines, one file per wire-shape family.
##
## `step_canvas: true` is the mandatory discriminator field — the SIXTH
## `Inbound` shape server/src/bridge/mod.rs demuxes on (star_map/city_names/
## browse/step_canvas, plus the two field-shape-disambiguated map probes).
##
## **Wire shapes (confirmed against server/src/atlas/step_canvas.rs, the
## authoritative source over any doc drift — T-1181's IMPLEMENTATION REPORT +
## WIRE SHAPE ADDENDUM, 2026-07-25):**
## StepCanvasRequest — a map: {step_canvas: true, body_id: String,
## rung: <bare string, one of "Global"|"Region"|"District"|"Quarter"|
## "Block"|"Chunk">, center: [i64, i64], extent: [u32, u32],
## min_wl_m: u32}. `rung` is a unit-variant enum, encoded as its Rust
## variant NAME verbatim (rmp_serde's bare-enum convention, same as
## granularity_v2/RoadNodeKind/CourseTerminus elsewhere on this wire).
## `center`/`extent` are meaningless for Global (server ignores extent
## entirely, center is echoed but unused) but are still sent — the
## request shape carries them unconditionally, no per-rung omission (the
## server-side struct has no Option on either field).
## StepCanvasResponse — a map: {body_id, rung, center: [i64,i64],
## extent: [u32,u32], min_wl_m: u32, status, canvas: null | EncodedStepCanvas}.
## `extent` is the server-CLAMPED echo (PR #201 review) — ALWAYS read
## this back, never assume the requested extent; `(0,0)` for Global (the
## wire extent is never read for that rung, so there is no clamped value
## to report). `status` is the same bare-string-or-{"Error":"msg"} shape
## every other status enum on this wire uses (Ready|Pending|NotFound|
## Error(String)) — decoded via the shared _decode_status_field() shape
## (duplicated here per browse_protocol.gd's own "genuinely standalone"
## precedent, not shared via a Callable).
## EncodedStepCanvas — a map: {width, height, morphology, elev_q, temp_dc,
## moisture_q, vegetation, settlement_id, glaciation, flooded_q, courses,
## cliffs}. The six PNG-per-field dense planes (morphology/elev_q/
## moisture_q/vegetation/glaciation/flooded_q) are each a map
## {"png_bytes": [...]} — png_bytes is a Rust `Vec<u8>` with NO
## serde_bytes annotation anywhere in this codebase (confirmed: grep for
## serde_bytes across server/src returns nothing), so serde's blanket
## Vec<T> impl serializes it via serialize_seq — a msgpack ARRAY of
## small-integer elements, NOT a `bin` blob. messagepack.gd's decoder
## therefore returns a plain GDScript Array (one int per byte), which
## this codec repacks into a PackedByteArray via the direct
## PackedByteArray(array) constructor before handing it to
## Image.load_png_from_buffer() — decode_png_field() below is the one
## place this conversion happens. temp_dc/settlement_id are the OTHER
## two dense fields, shipped raw MessagePack-native (too wide for an
## 8-bit PNG plane per EncodedTempField/EncodedSettlementField's own
## server-side doc): {"values": [...]} — i16/u32 arrays respectively,
## passed through as plain Arrays, no PackedByteArray repack (their
## per-cell domain doesn't fit a byte anyway). courses/cliffs are sparse
## MessagePack-native lists, passed through unshaped (the annotation
## layer owns interpreting RiverCourse/CliffSegment's own per-entry
## shape, matching atlas_map_protocol.gd's existing "raw passthrough,
## caller reshapes" precedent for district_window's courses field).
## Encode a StepCanvasRequest. `mp` is the loaded messagepack.gd module
## (passed in rather than reloaded here, matching every other codec in this
## cluster). `rung` is one of the six bare-string rung tags
## (StepCanvasTransport.RUNG_* constants) — sent verbatim, no client-side
## validation (the server rejects an unrecognized variant name at decode
## time per step_canvas.rs's own doc: "Unknown -> rejected, never trusted
## from the wire").
static func encode_step_canvas_request(
mp, body_id: String, rung: String, center: Vector2i, extent: Vector2i, min_wl_m: int = 0
) -> PackedByteArray:
var msg := {
"step_canvas": true,
"body_id": body_id,
"rung": rung,
"center": [center.x, center.y],
"extent": [extent.x, extent.y],
"min_wl_m": min_wl_m,
}
var result = mp.encode(msg)
if result.status != null:
push_error("StepCanvasProtocol: encode_step_canvas_request failed: %s" % result.status)
return PackedByteArray()
return result.value
## Shared status-enum decode — bare string ("Ready"/"Pending"/"NotFound") or
## a single-key map ({"Error": "message"}) for the one data variant. Same
## shape browse_protocol.gd/atlas_map_protocol.gd already implement for their
## own status enums; duplicated here rather than shared via a Callable to
## keep this file genuinely standalone (browse_protocol.gd's own stated
## rationale for its copy).
static func _decode_status_field(status_raw: Variant) -> Dictionary:
if status_raw is String:
return {"status": status_raw, "error": ""}
if status_raw is Dictionary and status_raw.has("Error"):
return {"status": "Error", "error": str(status_raw["Error"])}
return {"status": "", "error": ""}
## Repack a decoded {"png_bytes": [...]} field into a PackedByteArray ready
## for Image.load_png_from_buffer(). `field_raw` is the raw decoded Variant
## for one of the six PNG-per-field planes — null/malformed input returns an
## empty PackedByteArray (the caller's Image decode then fails gracefully,
## same "skip the bad entry" posture the rest of this cluster uses rather
## than crashing on a malformed wire payload).
static func decode_png_field(field_raw: Variant) -> PackedByteArray:
if not field_raw is Dictionary:
return PackedByteArray()
var bytes_raw: Variant = (field_raw as Dictionary).get("png_bytes")
if not bytes_raw is Array:
return PackedByteArray()
return PackedByteArray(bytes_raw)
## Build an EncodedStepCanvas Dictionary (GDScript-side shape) from an
## already-decoded raw value. Returns null if `raw` isn't a plausible canvas
## (missing width/height). PNG fields are repacked to PackedByteArray here
## (once, at decode time) — every downstream consumer (the terrain layer)
## works with real PackedByteArray/Image objects, never re-touches the raw
## msgpack Array shape.
static func _decode_encoded_canvas(raw: Variant) -> Variant:
if not raw is Dictionary:
return null
var d: Dictionary = raw
if not d.has("width") or not d.has("height"):
return null
var temp_dc_raw: Variant = d.get("temp_dc")
var settlement_id_raw: Variant = d.get("settlement_id")
return {
"width": int(d.get("width", 0)),
"height": int(d.get("height", 0)),
"morphology": decode_png_field(d.get("morphology")),
"elev_q": decode_png_field(d.get("elev_q")),
"temp_dc": (temp_dc_raw as Dictionary).get("values", []) if temp_dc_raw is Dictionary else [],
"moisture_q": decode_png_field(d.get("moisture_q")),
"vegetation": decode_png_field(d.get("vegetation")),
"settlement_id":
(
(settlement_id_raw as Dictionary).get("values", [])
if settlement_id_raw is Dictionary
else []
),
"glaciation": decode_png_field(d.get("glaciation")),
"flooded_q": decode_png_field(d.get("flooded_q")),
"courses": d.get("courses", []),
"cliffs": d.get("cliffs", []),
}
## Build a StepCanvasResponse Dictionary from an already-decoded raw value.
## Returns null unless it carries "rung" AND "status" — "rung" is the field
## no other decoded response on this wire has (atlas/citynames/browse all
## lack it), making it a safe, unambiguous discriminator for
## Protocol.decode_inbound()'s dispatch.
static func step_canvas_response_from_raw(raw: Variant) -> Variant:
if not raw is Dictionary or not raw.has("rung") or not raw.has("status"):
return null
var d: Dictionary = raw
var decoded_status := _decode_status_field(d.get("status"))
var center_raw: Variant = d.get("center", [0, 0])
var extent_raw: Variant = d.get("extent", [0, 0])
return {
"body_id": str(d.get("body_id", "")),
"rung": str(d.get("rung", "")),
"center": _vec_from_pair(center_raw),
"extent": _vec_from_pair(extent_raw),
"min_wl_m": int(d.get("min_wl_m", 0)),
"status": decoded_status["status"],
"error": decoded_status["error"],
"canvas": _decode_encoded_canvas(d.get("canvas")),
}
static func _vec_from_pair(pair: Variant) -> Vector2i:
if pair is Array and pair.size() >= 2:
return Vector2i(int(pair[0]), int(pair[1]))
return Vector2i.ZERO