Oxidized Navigation

Tiled Runtime Nav-mesh generation for 3D worlds in Bevy. Based on Recast's Nav-mesh generation but in Rust.

Takes in Bevy Rapier3D colliders from entities with the NavMeshAffector component and asynchronously generates tiles of navigation meshes based on NavMeshSettings.

Quick-start:

Nav-mesh generation:

1. Insert an instance of the NavMeshSettings resource into your Bevy app.
2. Add OxidizedNavigationPlugin as a plugin.
3. Attach a NavMeshAffector component and a rapier collider to any entity you want to affect the nav-mesh.

At this point nav-meshes will be automatically generated whenever the collider or GlobalTransform of any entity with a NavMeshAffector is changed.

Querying the nav-mesh / Pathfinding:

1. Your system needs to take in the NavMesh resource.
2. Get the underlying data from the nav-mesh using NavMesh::get. This data is wrapped in an RwLock.
3. To access the data call RwLock::read. This will block until you get read acces on the lock. If a task is already writing to the lock it may take time.
4. Call query::find_path with the NavMeshTiles returned from the RwLock.

Also see the [examples] for how to run pathfinding in an async task which may be preferable.

Supported versions

Note: These are the versions the crate is built against. It may work with newer versions.

Non-exhaustive TODO-list:

• Generate poly meshes for single tiles.

• Handle linking tiles together.

• Pathfinding across tiles.

• Generate tiles asynchronously

• Clean up intermediate representations when we finish processing a tile (Voxelized, Open cells, etc. Only keeping polymesh).

• Quick "How to use" guide.

• Built-in nav-mesh debug draw.

• Implement areas allowing to specify differing cost of traveling.

• Mark areas too close to walls as unwalkable based on character width.

• Allow creating nav-mesh from meshes (probably add an option to NavMeshAffector).

• Switch to the Bevy 0.9 plugin settings system.

• Code Tests.

• Benchmarks for tile generation & pathfinding.

• Optimize linking tiles. (At a cost of memory we can save a lot of time finding OffMesh links by just... saving indices of the polygons with OffMesh links)

• Adjust memory representation for cache usage. (Some data we only need when linking tiles and not pathfinding)

Debug draw.

Whilst not included in the plugin currently, you can use Bevy Prototype Debug Lines and the following snippet in a system to draw up the nav-mesh:

fn draw_nav_mesh(
    nav_mesh_settings: Res<NavMeshSettings>,
    nav_mesh: Res<NavMesh>,
    mut lines: ResMut<DebugLines>
) {
    // Probably want to add in a trigger key here to make it not always draw.

    if let Ok(nav_mesh) = nav_mesh.get().read() {
        for (_, tile) in nav_mesh.get_tiles().iter() {
            // Draw polygons.
            for poly in tile.polygons.iter() {
                let indices = &poly.indices;
                for i in 0..indices.len() {
                    let a = tile.vertices[indices[i] as usize];
                    let b = tile.vertices[indices[(i + 1) % indices.len()] as usize];

                    lines.line(a, b, 15.0);
                }
            }

            // Draw vertex points.
            for vertex in tile.vertices.iter() {
                lines.line(*vertex, *vertex + Vec3::Y, 15.0);
            }
        }
    }
}