Three live-found rendering bugs, all invisible to green unit suites:
- _draw_tile_mosaic placed tiles from absolute district (0,0); canvas-
local (0,0) is held_center - held_n/2 everywhere else, and tile-mode
held_n is the whole-body extent — the entire mosaic drew tens of
thousands of px off-canvas. New pure district_to_canvas_local() +
viewer accessors route every tile through the shared frame.
- _maybe_reselect_rung updated held_n across crossings without
recomputing _view_offset — the single-window composite landed off-
canvas the moment any crossing happened (why District/Quarter were
black too). New pure recompute_offset_for_held_n_change().
- _build_tile_texture created an unstored ImageTexture per _draw,
racing the RenderingServer's deferred upload — CPU pixels correct,
screen white. Per-tile-index texture cache, same reference-identity
discipline as the single-window _cached_texture.
Structural close of the twice-bitten 'nothing asserts pixels' gap:
test_atlas_window_overlay_draw_smoke.gd renders overlay output into a
SubViewport and asserts visible pixels for both modes — runs under a
real driver (invocation documented in DEVOPS.md, visual_capture
precedent; migration to the T-1157 harness noted on that ticket), skips
loud-but-green under the gate's headless run (verified green-with-skips
AND genuinely red with detection forced off). +7 geometry/crossing
tests, all revert-verified. Targeted suites 270 green; gdlint clean.