The runtime holds only the manifest pages its view needs, and the open world loads

[pasquelin]

Current scope — narrowed at claim time by CTO newest, 29 September

Compiler prerequisites #750, #762 and #792 are closed and delivered. This issue owns the runtime's view-bounded manifest lifetime on WebGL2 and the open-world loading proof.

Narrowed at claim time (29 Sept, CTO newest), before any code:

• Streaming without holes 10/12: world-scale roots, pinned memory independent of the world size #23's runtime items (world-roots reader and top-only pinning, parent→cell substitution, smallest-budget minimum capacity) and their Proof lines, including "JS heap bounded by the view (not the world) while flying across it", moved onto Streaming without holes: rules and objectives for geometry, memory and shadows #483, to be written as issues B1 and B2 once the boss agrees.
• WebGPU mounting of arriving primitives, the GPU DAG and request/key/draw-slot tables that grow in place, and the Streaming without holes 11/12: a large world loads its object table by distance, without crashing the tab #404 test on WebGPU moved onto Draw-slot tables grow in place when the geometry pool grows above its ceiling #216. WebGPU keeps the full manifest read until Draw-slot tables grow in place when the geometry pool grows above its ceiling #216 lands.

Why

Split from #404 (#483 rule 6). The runtime holds the whole manifest, so its memory grows with the world and the open world's tab crashes while reading it (JS heap 260 MB).

To do

• Core pages named by the format: the compiler writes the meshPages the core node table needs into the scene tables (format version bump, worlds re-cooked).
• The manifest held by the view (WebGL2): the runtime reads only the manifest root, head and core pages at open, through the one HTTP loader (fetchVerified, Audit of #438: a second scene model in the engine, witness code and Three.js wording left in the package #457), then fetches and keeps only the manifest pages the view's cells need (each cell's meshPages, counted per held cell), and drops them with the cells.
• WebGL2 mount and unmount: the primitives a page brings mount into the open WebGL2 session (mountPlacements) and unmount with the cell, with no session reopen.
• Bounds without every primitive: the scene opens while meshes have no primitive yet (no AUTONOMOUS_ASSOCIATION_MISSING).
• WebGPU unchanged: WebGPU keeps the full manifest read, with no image change, until Draw-slot tables grow in place when the geometry pool grows above its ceiling #216.
• The open world loads: trillion3d.commit in pasquelin/Trillion3D-openworld is bumped to this pull request's head in a pull request opened alongside it, and the world re-cooked, so the published /openworld/ reads its world without crashing the tab.

Code context

sdk-core/src/manifest/paged.ts, sdk-browser/src/scene/manifestLoad.ts, sdk-core/src/scene/core/tablePartition.ts, scene/partition/cells.ts, worldRuntime.ts, placement/autonomousPlacements.ts, world/scene/scene.ts, the compiler's scene tables.

Proof

• The measurer's open-world run: the tab loads the published /openworld/ without crashing; JS heap bounded by the view where the view's reach is smaller than the world (manifest pages dropped with their cells, WebGL2), recorded while flying across it.
• Streaming without holes 11/12: a large world loads its object table by distance, without crashing the tab #404 on WebGL2: zoom a partitioned world out to 0.5 with no missing object, and scale down a parent without a session reopen.
• The compiler writes the manifest in pages a reader fetches by region #750: scene tables load through the paged root with no image change.

Acceptance runs image/correctness checks; the measurer records memory/timing. Record the exact engine revision used.

Links

Parent #483. Split from #404. Delivered compiler prerequisites: #750, #762, #792. Moved out: #23's runtime items to #483 (future B1, B2); WebGPU growth to #216.

[pasquelin]

Open-world measurer proofs waiting on this issue (moved from #404, CTO): they run when it closes.

• Shadow performance programme: current shadows within 2 ms and a fluid native-resolution frame #525: shadow GPU ms per stage on an open world, reference path, ≤ 2 ms; still image A/A 0 px.
• Streaming without holes 6b/12: device loss rebuilt from the caches, CPU memory bounded, every out of memory absorbed #542: an open world with a forced device loss (time to the recovered frame, bytes refetched = 0, JS heap below the CPU total).
  The A frame target out of memory is absorbed: granted before drawing, Hi-Z dropped first, refused by name #725 branch proof's open-world part was also null for the same reason.

[pasquelin]

CTO: blocked by 762 (after #750). Known gap after both: the materials, textures and documents tables still grow with the world; they are the next step once the open world loads, measured first.

[pasquelin]

To do moved by the CTO from #404: rows counted in the one memory budget (rule 5); bare-explorer rows sized for the view, not the world; animated-parent placements kept in core; cells never starve page drains (rule 7). Proofs: the WebGL2 proof (rule 8) and the two-scene A/A (rule 9), run by the measurer.

[pasquelin]

To do moved by the CTO from #745: texture tiles use the one session budget instead of their own host-set per-frame ms ceiling in webgpu/tile/streamer.ts (#483 rule 4), after #404's budget.

[pasquelin]

Lead compiler, for the runtime once 750a (#750) is merged. The scene tables are now a fixed-size root of 8 slots. Each slot gives a page's hash, size and world box, index pages have the same fan-out, and pages are named by their content.

• Slot boxes are world boxes at the declared poses. If a core parent moves at runtime, its slot box no longer bounds its cells. The frame boxes per parent live only in the cell records. Read every page under a moved parent, or use those records.
• Loading. sdk-browser/src/scene/tables.ts:35 and tablePartition.ts:114 still read every page before the first frame, with an unbounded Promise.all. Reads driven by the view, bounded and cancellable through the one HTTP loader, belong here. Also count one extra round trip per index level before the first frame.

[pasquelin]

Open-world proofs waiting on this issue, added: #404 (a partitioned world zoomed out to 0.5 with no missing object, and a parent scaled down with no reopen).

[pasquelin]

Open-world proofs waiting on this issue, added: #750 (750a: the scene tables load through the paged root with no change in the image).

[pasquelin]

CTO: now blocked by 792 (after #762).

[pasquelin]

taken by CTO newest

[pasquelin]

Lead: coder started.