feat: enable LODs in worlds

[alejandro-jimenez-dcl]

Pull Request Description

What does this PR change?

Fixes #8892. Enables LODs in worlds through the ISS descriptor.

VisualSceneStateResolver short-circuited every fixed realm to SHOWING_SCENE, so world scenes never transitioned to SHOWING_LOD and the LOD/ISS systems introduced in #8870 never ran for worlds.

The gate is now descriptor-conditioned: an SDK7 world scene with a resolved ISS descriptor participates in the regular bucket-based LOD flow (full scene near, {sceneId}_ISS_LOD per-asset descriptor LOD at mid range, legacy LOD_1 AB at far range, unload when out of range). Worlds without descriptors, SDK6 world scenes,
LSD and portable experiences keep the current always-full-scene behavior.

Changes:

• VisualSceneStateResolver.ResolveVisualSceneState takes the scene's ISSDescriptor; fixed realms only resolve to SHOWING_LOD when the descriptor resolved to Descriptor state.
• ResolveSceneStateByIncreasingRadiusSystem passes the descriptor (already cached in OrderedDataManaged).
• New VisualSceneStateResolverShould unit tests covering world/volatile, SDK6/SDK7, descriptor states, and unload tolerance hysteresis.

No timing risk: the existing descriptor gate in ResolveSceneStateByIncreasingRadiusSystem already blocks any state transition until the descriptor resolves in place.

Test Instructions

Test Steps

1. Connect to cozyhouse.dcl.eth on zone, walk into 0,0: full scene loads.
2. Run away from the scene: the scene unloads and the LOD asset loads.
3. Walk back: LOD swaps back to the full scene

Additional Testing Notes

• Regression, worlds without descriptors (any production world on org): always full scene, unchanged.
• Regression, Genesis City on zone: LOD behavior unchanged.
• LSD and portable experiences opt out of ISS at construction, unaffected.

Quality Checklist

• Changes have been tested locally
• Documentation has been updated (if required)
• Performance impact has been considered
• For SDK features: Test scene is included

[github-actions]

Windows and Mac build successful in Unity Cloud! You can find a link to the downloadable artifact below.

Name	Link
Commit	5518aca
Logs	https://github.com/decentraland/unity-explorer/actions/runs/27020465813
Download Windows	https://github.com/decentraland/unity-explorer/suites/72558110958/artifacts/7439614940
Download Windows S3	https://explorer-artifacts.decentraland.org/@dcl/unity-explorer/branch/feat/enable-lods-worlds/pr-22771-5518aca/Decentraland_windows64.zip
Download Mac	https://github.com/decentraland/unity-explorer/suites/72558110958/artifacts/7439691290
Download Mac S3	https://explorer-artifacts.decentraland.org/@dcl/unity-explorer/branch/feat/enable-lods-worlds/pr-22771-5518aca/Decentraland_macos.zip
Built on	2026-06-05T15:01:28Z

[github-actions]

New build in progress, come back later!

[m3taphysics]

PR #8907, run #27022606716

Builds: Windows change, Windows baseline, macOS change, macOS baseline

How to read this table

• Each build is measured 3 times. The values are the median, and (min–max) is the lowest and highest of those runs — a wide range means the metric is noisy and small differences are not trustworthy.
• Δ is Change minus Baseline (a negative Δ means Change is faster).
• 🟢 faster / 🔴 slower — a real difference: larger than both 3% and the run-to-run range.
• ⚪ within noise — the difference is smaller than how much the build varies between its own runs, so it cannot be told apart from random variation. Treat it as no change.
• Exceptions logged — exceptions found in the run logs; more than the baseline is flagged 🔴 even when frame times look fine.

Framework 13 i7

Metric	Baseline	Change	Δ	Result
Samples	2700 (×3)	2701 (×3)
CPU average	33.3 ms	33.3 ms	-0.0 ms	⚪ within noise
CPU 1% worst	34.1 ms (34.0–34.2)	33.5 ms (33.4–33.7)	-0.6 ms	⚪ within noise
CPU 0.1% worst	39.8 ms (36.5–40.2)	34.3 ms (33.9–36.8)	-5.5 ms	🟢 14% faster
GPU average	7.6 ms (7.2–8.6)	8.3 ms (7.8–8.7)	0.7 ms	⚪ within noise
GPU 1% worst	19.5 ms (18.8–19.9)	17.8 ms (16.7–18.7)	-1.7 ms	⚪ within noise
GPU 0.1% worst	25.8 ms (23.1–26.3)	25.0 ms (20.8–25.3)	-0.8 ms	⚪ within noise
Exceptions logged	50	42	-8	🟢 fewer errors

[Ludmilafantaniella]

Tested on Windows and Mac. ✅

Main flow on zone (cozyhouse.dcl.eth):

• Full scene loads when walking into 0,0
• LOD asset loads when walking away
• Swaps back to full scene when walking back

Regression on org (Genesis City): LOD behavior unchanged.

LGTM 🚀

8907-evi.mp4

8907-evi2.mp4

✅Smoke test performed:

• ✔️ Backpack and wearables in world
• ✔️ Emotes in world and in backpack
• ✔️ Teleport with map/coordinates/Jump In
• ✔️ Chat and multiplayer
• ✔️ Camera
• ✔️ Skybox