navara-usage

name	navara-usage
description	Best practices for building 3D map applications with Navara (@navaramap/three). Use whenever writing or reviewing code that uses ThreeView, sources/layers/materials, plugins, mesh/effect/light descriptors, feature evaluation, picking, or geodetic math — in application code, examples, or documentation code snippets.

Using Navara (@navaramap/three)

Navara is a 3D globe map engine: reusable GIS logic lives in a Rust/WASM core, and drawing is delegated to a swappable CG-rendering library. @navaramap/three is the Three.js-based binding (currently the only one; more rendering engines are planned — avoid wording that fixes Navara to Three.js in prose). Its public API is ThreeView plus a declarative Source/Layer/Descriptor model.

Packages

Package	What it provides	When you need it
@navaramap/three	ThreeView (default export), Color, geodetic math utils, MeshDesc/EffectDesc/LightDesc base classes, handle types, built-in attribution UI (view.attribution, on by default)	Always
@navaramap/three_default_plugin	DefaultPlugin, DefaultDescriptions (registers ~40 built-in descriptors)	Almost always
@navaramap/three_default_descs	Individual descriptor classes/types (BoxMeshDesc, SSREffectDesc, SunLightDesc, …)	Typed addMesh<T>/addEffect<T> calls, or manual registration without DefaultPlugin
@navaramap/three_plugins	PersonViewPlugin, OverlayPlugin, CesiumIonPlugin, TileJsonPlugin	Per feature
@navaramap/three_api	Standalone GIS math (no view)	Pure geometry computation

Most apps need only the first two.

The canonical setup order (invariant)

import ThreeView from "@navaramap/three";
import { DefaultPlugin, type DefaultDescriptions } from "@navaramap/three_default_plugin";

const view = new ThreeView<DefaultDescriptions>({ shadow: true }); // 1. construct
const defaultPlugin = new DefaultPlugin();
view.addPlugin(defaultPlugin);                                     // 2. add ALL plugins — before init, or it throws
await view.init();                                                 // 3. async init (WASM + workers + pipeline)
defaultPlugin.addDefaultPhotorealScene();                          // 4. optional photoreal sky/sun/AA bundle
view.setCamera({ lng: 139.77, lat: 35.68, height: 10000, heading: 0, pitch: -30, roll: 0 });
const src = view.addSource({ type: "raster-tile", url: "https://tile.openstreetmap.org/{z}/{x}/{y}.png", maxZoom: 18 });
view.addLayer({ type: "raster", source: src });                    // 5. sources/layers/effects after init

When DefaultPlugin is used, parameterize the view as new ThreeView<DefaultDescriptions> so descriptor keys are typed.

Start from a recipe when building a scene

For "make it look good" goals, use the proven compositions in references/recipes.md (e.g. the photoreal base scene: DefaultPlugin + photoreal scene + Re:Earth quantized-mesh terrain + EOX satellite imagery + attribution) instead of assembling pieces from scratch.

Four capability tiers — pick the lowest that solves the problem

1. Declarative API — add sources and layers with plain config objects. Covers basemaps, terrain, vector data, 3D Tiles. → references/declarative-api.md
2. Low-level API — per-feature evaluation (FeatureEvaluator), picking, terrain sampling, geodetic/ECEF math. → references/low-level-api.md
3. Plugins — reusable purpose-built features (photoreal scene, first-person walk, DOM overlays, attribution), and how to write your own. → references/plugins.md
4. Custom descriptors — your own meshes/effects/lights, with access to the render pipeline, depth buffer, and normal/G-buffer (MRT). → references/custom-desc.md

Critical gotchas (apply everywhere)

• addPlugin() after init() throws. All plugin init()s run in parallel during view.init().
• Updates are partial merges: Layer.update(), Source.update() and mesh/effect/light handle .update() all merge into the current config — omitted materials and omitted fields within a material are preserved (verified: layer.update({ point: { color } }) keeps size/clampToGround). Note: Layer.update()'s JSDoc says "the entire configuration is replaced" — that text is outdated; trust the merge behavior shown in its own @example.
• Sources are reference-counted: source.delete() returns false while any layer still references it. Updating a source resets and reloads every referencing layer.
• Layer render order = add order (e.g. add terrain before the raster basemap draped on it).
• Never write to view.camera.raw frustum fields (fov etc.) — the engine overwrites them and Rust-side culling desyncs. Use the view.camera.fov/near/far setters.
• Units: mesh position is ECEF meters; sampleTerrainHeight/observeTerrainHeightAt take radians (use degreeToRadian); batch IDs are 24-bit.
• Mesh placement is Cartesian (ECEF) by default: raw position/rotation/scale are earth-centered ECEF meters, so a bare position won't sit upright at a lng/lat. For geographic placement set matrixWorld to a tangent-frame matrix — then position/rotation/scale become offsets within that frame. Pick the frame function whose axis orientation you want (all exported from @navaramap/three): eastNorthUpToFixedFrame (ENU), northEastDownToFixedFrame (NED), northUpEastToFixedFrame (NUE), northWestUpToFixedFrame (NWU). See references/low-level-api.md.
• Init-only options cannot change after init(): shadow, maxSse, segments, useNormal.
• Effect compatibility: hideUnderground: false and logarithmicDepthBuffer break some effect descriptors — test, and prefer defaults.
• picking: true (constructor, default on) is required for the pick event and pickable meshes.
• API stability tiers: ThreeView = Tier 0 (stable). Plugin + ViewContext = Tier 1 (may break between minor versions). Keep app code on Tier 0 where possible.

Lighting — when it's needed and which light to add

Lighting only affects surfaces that carry normals. Anything without normals is shaded uniformly (fullbright) and needs no light. But once normals are present, no light means the surface renders black. Add at least one light when you have:

• meshes / GLTF models that ship vertex normals
• quantized-mesh terrain loaded with requestVertexNormals: true
• raster-dem terrain rendered with a hillshade material
• the bare globe when the view was constructed with useNormal: true (init-only) — needed for the sun to shade the globe when no terrain or hillshade layer supplies normals

Built-in lights — register via DefaultPlugin, then view.addLight<T>({ ... }):

Descriptor	Key	Use
AmbientLightDesc	ambient	flat fill — raise overall brightness or light everything uniformly; no direction, no shadows
LightProbeDesc	lightProbe	pseudo-IBL from spherical-harmonics coefficients (e.g. a baked night ambient)
SkyLightProbeDesc	skyLightProbe	dynamic sky ambient that follows the sun through the atmosphere system
SunLightDesc	sun	directional sun; its direction is derived from atmosphere.date, and it casts CSM shadows

addDefaultPhotorealScene() already adds a sun + skyLightProbe — start there for realistic scenes and add ambient/lightProbe to taste.

atmosphere.date is local-time-sensitive. It's a plain JS Date, so new Date("2024-06-21T12:00:00") is read in the device's timezone — the sun lands in a different place per machine. Pin a global instant with an explicit UTC string (new Date("2024-06-21T12:00:00Z")). To hold the same time-of-day or sun elevation while flying the camera to another country, don't recompute by hand — use view.atmosphere.setDateFromCameraAt({ lng }) (keeps local solar time) or setElevationFromCameraAt({ lat, lng }) (keeps sun elevation).

Where to verify — never guess API details

Primary reference: the docs site — https://navara-docs.netlify.app/ (Japanese under /ja/). Sections: /three/ (core API: sources, layers, materials, camera, events), /three_default_descs/ (every built-in mesh/effect/light Descriptor and its options), /three_default_plugin/, /three_plugins/.

• Do not guess material or config property names — this skill shows patterns, not exhaustive option lists. Verify exact fields against the docs site, or the TypeScript definitions in node_modules/@navaramap/* (.d.ts).
• Working inside the Navara repository? The docs source is docs/src/content/docs/ and runnable examples are web/navara_three/example/pages/ — reference paths in this skill starting with example/pages/ refer to that examples directory.