engine.lines.createLine({ id, widthPx, color, depthFailAlpha, dash
({ lengthPx, gapPx } | 'tactical'), arc ('none'|'geodesic'), modelMatrix,
pickId }) → a Line: setPositions (Cartesian3[] or a flat Float64Array),
setColor, setModelMatrix, show, destroy; lines.list() for QA. Options,
flat positions, geodesic densification (great circles of the geodetic
normals, height interpolated, one step per degree) and the registry are
engine-neutral (src/globe/lines.js); the fake engine keeps every line.
- Cesium: a Primitive of a PolylineGeometry (synchronous, rebuilt when
the positions change) with a PolylineMaterialAppearance in an
engine-owned collection; depthFailAlpha is depthFailAppearance with the
alpha scaled; pixel dashes are PolylineDash (16-bit pattern); the
tactical dash is the launches' selected-orbit shader under its own type
(launches keep theirs until Task 15a moves them onto engine.lines).
- Navara: a public MeshDesc (transparent pass, unlit) holding a ribbon
of one quad per segment, widened to CSS pixels in the vertex shader;
a second copy drawn with GreaterDepth and the alpha scaled is the
depth-fail part; dashes are cut in the fragment shader (pixels along
the screen direction, or the tactical pattern over the fraction along
the line); positions relative to the first point, the model matrix on
the group. Geodesic arcs are densified on the CPU. Not pickable yet.
- The contract suite draws a three-point line on both engines: magenta
along both segments, nothing off it, 1° east once turned by its model
matrix, gone when hidden; a line 30 km under the ground shows only its
depth-fail copy, dimmer than the line.
Main chunk 2,867,499 bytes (+7,197, +0.25 %: the Cesium lines).
German Khokhlov
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