NullReferenceException when creating world in WASM compiled module

[l3dotdev]

Hi, thank you for this! Would you know why I am getting a NullRef exception when trying to create a world? The code is running inside of WASM

System.NullReferenceException: Arg_NullReferenceException
   at Box2D.NET.B2World.Clear()
   at Box2D.NET.B2Worlds.b2CreateWorld(B2WorldDef& )
   at StdbModule.Modules.World.WorldTick.CreateWorld()

private static B2WorldId CreateWorld()
{
    var def = new B2WorldDef
    {
        enableSleep = true,
        gravity = new B2Vec2(0, 0)
    };

    return B2Worlds.b2CreateWorld(ref def);
}

.NET version: 8.0.400
runtime: wasi-wasm

[ikpil]

It works fine for me, but it seems the environment might be a bit different.

After running:

dotnet new wasmconsole

using System;
using Box2D.NET;

var def = B2Types.b2DefaultWorldDef();
var worldId = B2Worlds.b2CreateWorld(ref def);

Console.WriteLine($"{worldId.index1}");

[l3dotdev]

Yeah, maybe I should have been more specific, it is running in a SpacetimeDB (https://spacetimedb.com/) server as a WASM compiled module so it uses the wasi-wasm runtime rather than browser-wasm.

Here's an MRE I've quickly put together: https://github.com/l3dotdev/box2d-net-in-spacetime-mre/tree/main

[ikpil]

I had the same issue, but adding Box2D.NET directly to the project instead of using NuGet worked fine for me. Could you check if that works for you as well?

PS C:\workspace\box2d-net-in-spacetime-mre> spacetime publish --project-path ./Module box2d-net-in-spacetime
Optimising module with wasm-opt...
Could not find wasm-opt to optimise the module.
For best performance install wasm-opt from https://github.com/WebAssembly/binaryen/releases.
Continuing with unoptimised module.
Build finished successfully.
Uploading to local => http://127.0.0.1:3000
Publishing module...
Updated database with name: box2d-net-in-spacetime, identity: c2007ddd393afffaefd9a9087b9d259602da9222646c630e4a9b72b54da1bc03
PS C:\Users\ikpil\workspace\box2d-net-in-spacetime-mre>

[ikpil]

Oh, and when creating a definition for world creation, please use the b2DefaultWorldDef function.
It performs the basic setup that needs to be done by default.