"unreachable" error when using heightmap

[viridia]

I'm getting the following error:

Uncaught RuntimeError: unreachable
    at std::panicking::rust_panic_with_hook::h9d91fa0fae16500f (http://localhost:3000/0c0ef481b8428110185b.module.wasm:wasm-function[788]:0x108529)
    at std::panicking::begin_panic_handler::{{closure}}::h2d82b5b2db976f3f (http://localhost:3000/0c0ef481b8428110185b.module.wasm:wasm-function[897]:0x10d32a)
    at std::sys_common::backtrace::__rust_end_short_backtrace::h24539600b7e2452c (http://localhost:3000/0c0ef481b8428110185b.module.wasm:wasm-function[1245]:0x114d35)
    at rust_begin_unwind (http://localhost:3000/0c0ef481b8428110185b.module.wasm:wasm-function[1161]:0x113c87)
    at core::panicking::panic_fmt::h91d2023e5afe1929 (http://localhost:3000/0c0ef481b8428110185b.module.wasm:wasm-function[1247]:0x114d99)
    at core::panicking::panic::h5da66f104e83c46a (http://localhost:3000/0c0ef481b8428110185b.module.wasm:wasm-function[1111]:0x112e78)
    at rapier3d::geometry::broad_phase_multi_sap::sap_axis::SAPAxis::batch_insert::h22440a950023a6c1 (http://localhost:3000/0c0ef481b8428110185b.module.wasm:wasm-function[58]:0x6e464)
    at rapier3d::geometry::broad_phase_multi_sap::broad_phase::BroadPhase::update::hcb9a53f41ef84931 (http://localhost:3000/0c0ef481b8428110185b.module.wasm:wasm-function[46]:0x5b78c)
    at rapier3d::pipeline::physics_pipeline::PhysicsPipeline::detect_collisions::he6a99ba9c9b1190f (http://localhost:3000/0c0ef481b8428110185b.module.wasm:wasm-function[321]:0xdbb17)
    at rapier3d::pipeline::physics_pipeline::PhysicsPipeline::step::h0bcdada6b45b091e (http://localhost:3000/0c0ef481b8428110185b.module.wasm:wasm-function[45]:0x59992)

What is interesting is that if I fill the heightmap with all zeroes, I don't get this error. If I pass in real terrain data I do.

Even more strangely, if I multiply the data by a small constant (.01) the error goes away, but I multiply by (.99) it happens. So basically it is as if the magnitude of what is in the array matters. I've tried a bunch of other combinations, it's completely consistent but I can't figure out the pattern.

Note: it took me a few hours to even get this stack dump, as I had to build the library locally in order to turn on debug symbols, and I had to fuss with it to get it to build on my system.

The way I am building the height map isn't very interesting either:

/** Physics object representing a height field such as terrain. */
export class PhysicsHeightField {
  #body: RigidBody;
  #collider: Collider | null = null;

  constructor(private rapier3d: R, private world: World, position: Vector2) {
    // TODO: Add friction and such.
    const rbDesc = rapier3d.RigidBodyDesc.newDynamic().setTranslation(position.x, 0, position.y);
    this.#body = this.world.createRigidBody(rbDesc);
  }

  public dispose() {
    if (this.#collider) {
      this.world.removeCollider(this.#collider);
      this.#collider = null;
    }
    this.world.removeRigidBody(this.#body);
  }

  public setHeights(heights: Float32Array) {
    // Remove previous collider, if any.
    if (this.#collider) {
      this.world.removeCollider(this.#collider);
    }
    // Generate new height map from data.
    const clDesc = this.rapier3d.ColliderDesc.heightfield(
      PLOT_LENGTH,
      PLOT_LENGTH,
      heights,
      terrainScale
    );
    this.#collider = this.world.createCollider(clDesc, this.#body.handle);
  }
}

[viridia]

So changing it to static made the problem go away - still don't know why.

I'm finding it very difficult to debug problems, such as when I pass in a bad param - it just throws "unreachable" with no explanatory message as to what went wrong.

[aunyks]

Thanks for following up with how you've solved this. I'm running into the same error with the Heightfield but making it Static hasn't worked yet. I'll follow up if I find a solution, for others who are running into this.

[sebcrozet]

@aunyks Are you using the latest version of Rapier? This issue may be related to a bug that has been fixed recently. If you are using the latest version, could you please provide a piece of code to reproduce it?