Navara's ground pass cut each corridor into chunks and tested them per
screen cell, so dense corridor sets were slow (10,000 cost about 150 ms a
frame). A corridor set is now cut into pieces along its great circles,
sorted into lon/lat tiles, each with a pyramid of bins listing the
segment runs within its margin; a pixel takes its tile and the finest
bin that covers its reach and tests only those runs. At 10,000 corridors
a frame now takes 11.8 ms still (Cesium 23 ms), at 15,000 17.9 ms. A
pixel corridor's width is measured across the line, so diagonal lines no
longer draw up to 1.4 times wider.
Pixel corridors take three looks, evaluated on the GPU from a time
uniform: Cesium's PolylineGlow falloff (glow), an alpha pulse and the
annotation route's flowing dash. While a shown set pulses or flows the
engine draws continuously, as Cesium did. Traffic's jam lines take the
glow and pulse again and the Directions route its flowing dash and render
hold, so on Cesium both match the drawing before they moved to the
contract pixel for pixel. The contract suite passes on both engines
(Cesium 69/69, Navara 72/72).
src/app/layers/renderers.js now holds LAYER_MANIFEST, one entry per
layer in directory order: a display (the same render/display.js on every
engine, with the contract primitives it needs and, for CCTV and Global
Context, a Navara backend loaded by import()), a layer that draws itself
through the contract, or per-engine renderers for the layers not on a
display yet (weather, wind, Bhote Koshi, sea marks, ski pistes). A layer
is available where the engine has the primitives it needs. The Cesium
renderer table, CESIUM_BUILTIN, the registry and the Navara mode's map of
about 35 loaders go; the application loads a kind's renderers before it
builds the catalog.
The tools attach through one tree over the engine, in Cesium's order.
Each engine kind adds its own tools from one backend that reads its
extension once: the Cesium backend holds the viewer-only tools, the
Navara backend the annotation renderer, draw surface and file import
drawing.
Coupling: engine.extensions reads fall from 12 to 8, engine-name literal
lines from 73 to 66.
engine.imagery draws raster layers over the globe: Web Mercator tile
templates and single images or canvases stretched over a rectangle, with
alpha, show, a left/right split against the engine's split position and
an order. A layer's source can be replaced in place.
- Cesium puts one ImageryLayer per layer on the globe's imagery stack,
or on the shown 3D tileset's when the globe is hidden, and moves it
when the surface changes; the Recent Imagery request gate moved here.
- Navara draws them in one screen pass after tone mapping that samples up
to eight layers by geodetic position from mipmapped textures and a tile
atlas, under the other drapes and engine.ground.
- The fake engine keeps each layer's state.
The FIRMS far-zoom heat raster and Recent Imagery now draw through it, so
FIRMS' heat seam and both its backends, and Recent Imagery's Cesium and
Navara renderers and tile plan, go. Against HEAD, Cesium's pixels are
identical in all four compared scenes; Navara's orbital heat changes by a
mean of 3.8 from new mipmapping, slightly towards Cesium. The contract
suite passes on both engines (Cesium 68/68, Navara 71/71).
engine.maps.addOverlay stays a Navara-only extension for Sea Marks and
Ski Pistes until imagery has a finer tile path for oblique global views.
engine.ground draws sets of polygons (with holes), discs, cells and
corridors draped on the surface, with fill and outline colours, order and
picks, written in bulk and committed. Every engine implements it:
- Cesium batches each set into one GroundPrimitive for fills and one
GroundPolylinePrimitive for outlines and pixel corridors, classified
against terrain and 3D tiles; sets that are not pickable stay out of the
pick pass.
- Navara draws them in one screen pass after tone mapping that finds each
pixel's ground from the scene depth and tests the items in its screen
cell; long rings are split into edge bins. Measured at Dubai against
SDK vector layers, the pass matched Cesium's frame time up to 10,000
polygons with a few megabytes instead of 70 to 146, drew exact colours
and outlines, and hid reliably across an engine switch, where vector
layers hidden with update({ show: false }) never hid. Dense corridors
remain its limit (10,000 cost 135 ms a frame).
- The fake engine keeps the same registry and CPU picks.
The contract suite checks it on both engines (Cesium 66/66, Navara 69/69).
Earthquakes and fire perimeters have unwired ground prototypes whose
drawing matches today's Cesium one (0.998 on Cesium, 0.976 on Navara).
docs/GLOBE-PRIMITIVES.md describes the primitives and when to use each.
German Khokhlov