User report: the graph "disappeared". Reproduced, and the cause was not the
graph at all — the panel's main thread was blocked hard enough that the browser
stopped responding to clicks.
Root cause, found by measuring rather than guessing:
rAF 2 FPS, setTimeout(0) lag 1353ms, with the graph rendering correctly the
whole time. The scene was repainting continuously at 60fps even though it is
static between the 10s data refreshes. Each repaint cost ~305ms on this
host's software GL, so the main thread never got a free slot.
Fixes:
- Render on demand. The ticker is registered but not started; it runs only while
an attack pulse is in flight or the user is dragging, and stops once the scene
is quiet. applyView() (the single funnel for pan/zoom/drag/refit) repaints
synchronously. Result: 2 FPS -> 73 FPS, 1353ms -> 2ms lag. That is faster than
a blank page in the same harness (29 FPS), which confirms the ticker was the
cost, not the scene complexity.
- Stop rebuilding Pixi objects every refresh. _redrawEdges destroyed and
recreated ~70 Graphics + ~36 Text each cycle; every new Text allocates a
canvas, rasterises glyphs and uploads a texture. Edges are now kept per
from->to key and only their geometry is redrawn; a label's text is re-set only
when the string actually changes. Same for node titles/subtitles.
- Bind tooltip handlers once, at node creation. Re-binding inside the refresh
loop added a pointerover listener every 10s, so a single hover after an hour
fired thousands of handlers.
Two correctness bugs fixed while in there:
- init() race. The Topology tab button calls showView('topo') AND loadTopo(), and
showView() itself calls loadTopo(), so two ran concurrently. The re-entry guard
tested `topoGraph && topoGraph.app`, but topoGraph was assigned BEFORE the
awaited init(), so app was still null and a second renderer was built. Both
cleared host.innerHTML and appended their own canvas, so the last init to
finish won the DOM while the bridge still pointed at the other — a live canvas
that was no longer on the page. Now guarded by a single-flight promise, and
the instance is published only after init() resolves.
- Dropped the dead topoLoaded flag left over from the SVG renderer.
Hierarchical drag: dragging a team now carries its 16 challenge nodes with it.
The parent->children index is built from the edge list, the same source the
lines are drawn from, so the drag hierarchy cannot disagree with the picture;
challenges missing from the edge list still attach by id prefix. Children
translate rigidly (verified: 0.000px deviation across all 16).
Verified from a cold panel restart: all 5 topology tests pass, 73 FPS, 2ms
lag, 37 nodes drawn, graph framed at 4 viewport widths, no page errors, and
platform SLA unregressed at 32/32.
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