Add BasisHighlight render feature

[BoatFloater]

Summary

I'd like to backport an outline/highlight feature I was working on in my own project to the Basis framework since I've been thinking about it recently. Let me know if you're interested. It is implemented as a custom render feature/pass, which there aren't currently any in the Basis framework.
Changes:

• BasisHighlight
  • A new framework-level render feature/pass to generate object outline highlights. It's built to be a relatively generic system which could be used by various sub-systems.
  • The render pass/feature are mostly vibe-coded, but it seems like the performance is good. It would be good to have a review by someone more experienced with URP. The changes to Basis internals are implemented by hand.
• BasisPickupInteractable
  • Refactored to use BasisHighlight instead of its own highlighting system. The collider proxy system is re-used as a fallback if no MeshRenderer are found
• PickupHighlightColor
  • Renamed HighlightColor since it could be used for things other than pickup (if approved, all locales will need modification)
• Examples
  • Refactor the example button to use BasisHighlight in addition to its material recoloring
  • Add a Highlight examples folder with the vertex offset shader to showcase BasisHighlightOverride
• BasisPlayerInteract
  • Not strictly related to the highlight feature, but I made the desktop line indicate from the dominant hand side of the screen and adjusted the destination point to be a bit more out of the way
• Prefabs
  • Re-enabled highlight on the personal mirror since it is an outline without fill; I suppose it's still a matter of personal preference
• Content Police
  • Allow BasisHighlightOverride component on Props, Scenes, and System

Example

a1775082-4792-47c6-8277-ce5591ef4c64.mp4

BasisHighlightOverride

Setting a custom mask material so the outline can match vertex deform

d6eb27a3-d4fd-474f-b6a6-a6a6d1611bd0.mp4

BasisPlayerInteract

Use dominant-hand and push nearest point out of the way

BasisHighlightSettings

These are the settings I currently have set for both Desktop and Android, but they can be changed individually. I haven't tested on Android. The color is overridden by the runtime setting.

Required checks

All boxes below must be ticked before this PR can merge. If a check is genuinely N/A, tick it anyway and explain under Notes.

• Tested — I built and ran this locally. The change works in the editor and (where relevant) in a built player.
• Transform access is combined and limited — In hot paths, transform reads/writes go through TransformAccessArray or are otherwise batched. I have not added per-frame transform.position / transform.rotation / transform.localPosition calls inside loops. Whenever I need both position and rotation, I use the combined APIs — SetPositionAndRotation / SetLocalPositionAndRotation for writes, GetPositionAndRotation / GetLocalPositionAndRotation for reads — instead of two separate property accesses; the combined call does one local-to-world matrix traversal instead of two.
• Addressables used for asset/memory loading — Any new asset loads go through Addressables. No new Resources.Load, no direct asset references that pull large content into memory on scene load.
• No new GetComponent / AddComponent where avoidable — Where unavoidable, the result is cached on a field, and any GetComponent<T> is replaced with TryGetComponent<T>(out var x) — bare GetComponent will be denied. TryGetComponent is the modern API (Unity 2019.2+) and skips the Editor-only GC allocation GetComponent causes when a component is missing: Unity wraps the null return in a managed "fake null" object so its overloaded == operator can still detect destroyed C++ objects, and constructing that wrapper allocates; TryGetComponent returns a bool plus out parameter and never builds the wrapper. None of these calls run inside Update, LateUpdate, FixedUpdate, jobs, or other per-frame code paths.
• Per-frame work is scheduled through BasisEventDriver — Any new per-frame work hooks into BasisEventDriver rather than adding standalone Update / LateUpdate / FixedUpdate callbacks on a MonoBehaviour.
• Anything added to BasisEventDriver is bulletproof, or guarded by try/catch — BasisEventDriver runs the single per-frame tick that drives the whole framework (network apply, local player sim, blendshapes, JigglePhysics, nameplates, and more) as one sequential chain. An unhandled exception anywhere in that chain aborts the rest of the tick, so every step after the throwing one is silently skipped for that frame. New work added to the driver must either be guaranteed not to throw, or be wrapped in a try/catch that contains the failure and surfaces it through BasisDebug — logged once / rate-limited, never every frame (see the existing HVRBasisBuiltInAddresses.Simulate() guard for the pattern). Expect this to be scrutinized closely in review.
• Considered jobification — I asked whether this work can be moved to a Unity Job (Burst-compiled where possible). If it can, it is. If it cannot, the reason is in Notes.
• No needless { get; set; } properties or access lockdowns — Public fields are fine; Basis is meant to be read and modified freely, so don't wall things off private/internal without a real reason. Don't wrap a field in { get; set; } when the accessors do nothing — property accessors have a real performance cost vs direct field access, and the lead maintainer prefers plain fields (or a method / setter-only property when only the setter needs logic) over a noop-getter pair. For .Instance singletons, callers reassigning Type.Instance is allowed; if that would break your code, log a warning or throw — don't block the assignment. Locking down access is not your call.
• Camera access goes through BasisLocalCameraDriver — Code that needs the local camera (transform, projection, rig data, etc.) pulls it from BasisLocalCameraDriver rather than looking one up itself. Don't roll a separate camera discovery path.
• Logging uses BasisDebug — All new logging calls go through BasisDebug.Log / BasisDebug.LogWarning / BasisDebug.LogError (with an appropriate LogTag) instead of UnityEngine.Debug.Log / Debug.LogWarning / Debug.LogError. BasisDebug routes through Basis's tagged, color-coded logger and respects the project-wide LoggingDisabled toggle so logging can be killed at runtime; bare Debug.Log calls bypass that and will be denied.
• No scene-wide discovery for dependencies — New code is architected so it does not need FindObjectOfType / FindObjectsOfType / GameObject.Find / FindGameObjectsWithTag to locate what it depends on. References are wired in — registered through an existing manager/driver, injected at init, or passed in by the caller — rather than discovered by scanning the scene at runtime. If a scene scan is genuinely unavoidable, justify it under Notes.
• No allocations in hot paths — Per-frame code (Update / LateUpdate / FixedUpdate, simulation loops, jobs, anything called once per frame or more) does not allocate. No new on reference types, no LINQ, no string concatenation/interpolation, no boxing, no foreach over interface-typed collections. Allocate once at init and reuse the buffer.
• No debugging in hot paths — No log calls of any kind on per-frame paths, including BasisDebug. Hot-path logging floods the console and incurs cost on every frame regardless of whether the message is filtered out downstream. If a hot-path log is needed while iterating, gate it behind #if UNITY_EDITOR and remove (or leave gated) before merge.
• Hot-path collection access is optimized — Cache .Count (lists) / .Length (arrays) into a local int before the loop instead of re-reading the property each iteration. Prefer T[] (with a separate length int when the array is over-sized) over List<T> where the data is hot — Unity's mono BCL doesn't expose CollectionsMarshal.AsSpan(List<T>), so a list can't be fed into Span<T> / unsafe paths cleanly. Where the perf justifies it, drop into Span<T> / ref locals / Unsafe.As / unsafe pointer code to skip bounds checks and copies, and call out the invariants you're relying on under Notes so reviewers can sanity-check them.

Testing details

Tick the platforms you actually tested on. Leave the rest unticked — these are informational and do not block merge.

• Windows
• Linux
• Android
• iOS
• macOS

Input / control mode coverage:

• Tested in VR (note headset under Notes)
• Tested in desktop / non-VR mode
• Tested with phone controls (mobile touch input)
• N/A — change does not touch player/XR/input code

Where applicable, confirm these flows still work after your changes:

• Hot-switching (desktop ↔ VR mode swap at runtime)
• Avatar swapping
• Server swapping (joining / leaving / changing servers)
• N/A — change does not touch any of the above

Notes

Tested on PC in flat mode & with Valve Index

[dooly123]

How does it go on Quest/Android? (performance wise)

[dooly123]

happy to get it in overall, just need to make sure we are not impacting our weakest targets

[BoatFloater]

@dooly123 I don't currently have a good way to test the performance on Quest; I will look into trying to set that up, but it would be good if someone who normally runs Basis on Quest could confirm.
Theoretically the shaders are written in a way that should run fine on the Quest GPU, and the default highlight settings could be lowered for Android if necessary.

[BoatFloater]

I was able to get it up and running on Quest (2), in spite of all apparent efforts of the great team over at Meta.

I had to enable requiresIntermediateTexture for it to work on Quest. The glow passes also tanked performance, so I disabled glow and tuned some other settings for Android.

The new settings don't appear to affect my fps (read from the Basis menu) at all between 0 hovered objects (render pass is skipped) and 2 sustained hovered objects, though there appears to be a brief 1-4fps dip right when an object is first hovered; I'm not sure how that compares to developer though.

It would be good to get feedback from more people.

New Android Settings