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kids.kapish.splines.vista ​

unity

Bridge that enables Vista's Unity Splines support automatically.

Installation ​

Add to your Unity project's package manifest:

json
{
  "kids.kapish.splines.vista": "file:../../src/unity/kids.kapish.splines.vista"
}

Editor-only. Requires Unity 6000.0+, and is only meaningful with Vista + Unity Splines installed.

Architecture ​

The problem ​

Vista's UnitySplineEvaluator and spline Path node are gated on #if VISTA_UNITY_SPLINE. Vista's own ModuleInitializer tries to set that symbol via a csc.rsp it writes into its vendor folder when it detects UnityEngine.Splines. That works, but the csc.rsp is regenerated on import and is assembly-local, so the evaluator can drop out and the usual "fix" is hand-editing Vista's files — which is then lost on the next Vista update.

The fix ​

Own the toggle as a global, durable project define rather than a vendor file:

  • defineConstraints: ["VISTA"] — the assembly compiles only in a Vista project, so it never touches non-Vista projects.
  • Package depends on com.unity.splines — so by the time this package is installed, Unity Splines is guaranteed present. (Setting VISTA_UNITY_SPLINE without Unity Splines would make Vista's evaluator fail to compile, so this precondition matters.)
  • [InitializeOnLoad] adds VISTA_UNITY_SPLINE to the active build target's scripting define symbols, add-only and idempotent — if it's already set it returns immediately, so it never starts a recompile loop.

A global define satisfies #if VISTA_UNITY_SPLINE in Vista's own assembly regardless of the state of Vista's csc.rsp, which is why this is more robust than the vendor mechanism.

Why a separate package ​

The dependency graph stays clean only if this lives on its own:

kids.kapish.splines  ←  kids.kapish.splines.paths   (paths needs splines, not vista)
       ↑
kids.kapish.splines.vista  (needs splines + vista — the intersection)

kids.kapish.terrains  ←  kids.kapish.terrains.vista  (vista nodes, must not need splines)

Putting the define in terrains.vista would force terrains → splines; putting it in splines.paths would force paths → vista. Neither is acceptable, hence the dedicated intersection package.

Multi-width path evaluator ​

PathVistaLink registers three Vista spline evaluators from a single SplineContainer. Vista discovers evaluators through SplineModuleUtilities.collectSplines — a static event raised with a queried id; each subscriber adds itself if its id matches. Vista's stock UnitySplineEvaluator is [RequireComponent(SplineContainer)] with one width and one id, so three widths would mean three spline objects. Instead this component subscribes to the collect event and answers for {id}--thin, {id}--path and {id}--wide, each backed by a lightweight ISplineEvaluator (a private RibbonEvaluator) generating ribbon geometry at its own width off the shared spline.

The ribbon layout is a faithful copy of Vista's: four triangles per segment, centre-line vertices alpha 1 and edge vertices alpha 0, normal = cross(tangent, up) (optionally flattened to horizontal), width ±half each side — so the masks are indistinguishable from a native Vista Path node fed by a stock evaluator. Widths: --path = pathWidth, --thin = thinWidth, --wide = pathWidth + 2·edgeWidth. Gated VISTA_UNITY_SPLINE && !VISTA_EXCLUDE_PRO (needs Unity Splines + Vista Pro) — the symbol this package's editor bootstrap guarantees.

File Structure ​

Runtime/
├── PathVistaLink.cs          (+ private RibbonEvaluator : ISplineEvaluator)
└── Carrot.Splines.Vista.asmdef          (defineConstraints ["VISTA_UNITY_SPLINE", "!VISTA_EXCLUDE_PRO"])

Editor/
├── VistaUnitySplineDefine.cs
└── Carrot.Splines.Vista.Editor.asmdef   (Editor, defineConstraints ["VISTA"])

Limitations / notes ​

  • Add-only: it does not remove VISTA_UNITY_SPLINE if Unity Splines is later removed. In practice UPM won't let com.unity.splines be removed while this package depends on it, so the precondition holds.
  • Sets the symbol for the active build target. Vista's own csc.rsp still covers its assembly across targets; this guarantees the editor sees it.

Build ​

Import via Unity Package Manager. Editor-only. Requires Unity 6000.0+.

Usage Guide ​

Bridge that enables Vista's Unity Splines support automatically.

Setup ​

  1. Have Vista and Unity Splines (com.unity.splines) in the project.
  2. Add kids.kapish.splines.vista to the manifest.
  3. Let Unity reload. On load it ensures VISTA_UNITY_SPLINE is defined, Vista recompiles once, and the Unity Splines evaluator / spline Path node become available in Vista graphs.

There's nothing to configure and no component to add — it's a one-shot editor bootstrap.

Verifying ​

After the reload, check Project Settings → Player → Scripting Define Symbols contains VISTA_UNITY_SPLINE, and that Vista's Path node lists Unity Spline as an evaluator.

Notes ​

  • No Vista? No effect. The assembly only compiles under the VISTA define, so this package is inert in non-Vista projects.
  • Don't hand-edit Vista's csc.rsp anymore. That's the thing this package replaces; editing it was the symptom, not the fix.
  • Re-rolling Vista updates won't lose the define — it lives in your project settings, and this package re-asserts it on every load anyway.

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