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Unofficial ChilloutVR Reference

WASM Scripting

TL;DR: CVR runs user-written scripts as WebAssembly modules via embedded Wasmtime 34. Authors write C#, the CCK compiles it to .wasm using the .NET 10 preview NativeAOT toolchain (ILC + WASI SDK 25), and the CVR client loads one module per root content (avatar / prop / world) — not one per component. Access to Unity and CVR APIs is mediated by a three-axis permission system.

Status: the C# WASM scripting runtime is currently in closed (invite-only) testing. The long-term plan is to replace CVR’s existing Lua scripting with this system. Parts of the surface and toolchain may shift before general release.

How this section is organized

Section titled “How this section is organized”

Start here

Section titled “Start here”
  • Quickstart — zero to a running “Hello, world!” script in five minutes.

Concepts

Section titled “Concepts”
  • Architecture — Wasmtime wiring; one Store per content root; 100 kHz epoch interruption.
  • Runtime Lifecycle — build → load → instantiate → event dispatch → dispose.
  • Authoring — subclass WasmBehaviour, detect events by method name, attach via CCKWasmProjectDescriptor.
  • Events — Unity lifecycle events, physics events, and game events a script can handle; disallowed events.
  • Permissions — three-axis access check (ObjectContext × OwnerContext × ScopeContext).
  • World Permissions — user-approved capabilities (identity, HTTP domains, storage quota).
  • Serialization — [WasmSerialized], [NonWasmSerialized], default behavior.
  • Limits — epoch deadline, storage quota, disabled WASM features.
  • Unity Events Rewiring — how Button.onClick in Unity is redirected to WASM at build time.

Build

Section titled “Build”
  • Build Pipeline — dotnet publish flow, generated WasmModule.csproj, on-demand tool install.

IO

Section titled “IO”
  • Networking — SendType, per-message buffering, ping / MTU / clog checks.
  • File Storage — per-world XOR-encrypted key-value store; quotas.

Performance

Section titled “Performance”
  • Performance — interop cost, caching, batching, allocation hygiene.

API Reference

Section titled “API Reference”
  • API Overview
  • CVR Host Functions — everything in the CVR import module (CVR_Player_*, CVR_Avatar_*, CVR_WasmUtils_*, CVR_WorldSettings_*, etc.).
  • UnityEngine Surface — ~280 generated bindings across UnityEngine (169), UnityEngine.AI (24), Audio (4), Rendering (54), UI (3), SceneManagement (1), EventSystems (1), Experimental.Rendering (7), TMPro (16), CVR (5).
  • Not Exposed — what the sandbox explicitly denies (Input, Application, IO, Net, Reflection.Emit, etc.).

Examples

Section titled “Examples”

Context packs: Avatar · Prop · World.

UdonSharp Ports — five community packages and six quick snippets ported from VRChat Udon.

On-disk sources

Section titled “On-disk sources”
  • Host runtime — CVR-GameFiles/ABI_RC.Systems.WasmScripting/, CVR-GameFiles/WasmScripting/, CVR-GameFiles/WasmBinder.Links.*/, CVR-GameFiles/WasmBinder.LinksManual.UnityEngine/.
  • Authoring package — CVR.CCK.Wasm/CCK/ (editor), CVR.CCK.Wasm/Scripting/ (attributes, enums, helpers).
  • Wasmtime — CVR.CCK.Wasm/Packages/Wasmtime.34.0.2/ (native + .NET wrapper).