bevy_landmass

A plugin for Bevy to allow using landmass conveniently.

Overview

bevy_landmass allows using a navigation mesh to determine the desired move direction for characters using pathfinding.

To use bevy_landmass:

1. Add LandmassPlugin to your app.
2. Spawn an entity with an Archipelago component.
3. Spawn an entity with an IslandBundle, and an IslandNavMesh component.
4. Spawn entities with the AgentBundle and a TransformBundle (or any other bundle which includes a Transform and GlobalTransform).

Note the Archipelago can be created later, even if the agents/islands already have an ArchipelagoRef to it. Agents/islands will be added once the Archipelago exists.

Example

use std::sync::Arc;

use bevy::{app::AppExit, prelude::*};
use bevy_landmass::prelude::*;

fn main() {
  App::new()
    .add_plugins(MinimalPlugins)
    .add_plugins(AssetPlugin::default())
    .add_plugins(TransformPlugin)
    .add_plugins(LandmassPlugin)
    .add_systems(Startup, set_up_scene)
    .add_systems(Update, print_desired_velocity.after(LandmassSystemSet::Output))
    .add_systems(Update, quit.after(print_desired_velocity))
    .run();
}

fn set_up_scene(
  mut commands: Commands,
  mut nav_meshes: ResMut<Assets<NavMesh>>,
) {
  let archipelago_id = commands.spawn(Archipelago::new()).id();

  let nav_mesh_handle = nav_meshes
    .get_handle_provider()
    .reserve_handle()
    .typed::<NavMesh>();

  commands
    .spawn(TransformBundle::default())
    .insert(IslandBundle {
      island: Island,
      archipelago_ref: ArchipelagoRef(archipelago_id),
      nav_mesh: Default::default(),
    })
    .insert(nav_mesh_handle.clone());
  
  // The nav mesh can be populated in another system, or even several frames
  // later.
  let nav_mesh = Arc::new(NavigationMesh {
      mesh_bounds: None,
      vertices: vec![
        bevy_landmass::Vec3::new(1.0, 0.0, 1.0),
        bevy_landmass::Vec3::new(2.0, 0.0, 1.0),
        bevy_landmass::Vec3::new(2.0, 0.0, 2.0),
        bevy_landmass::Vec3::new(1.0, 0.0, 2.0),
        bevy_landmass::Vec3::new(2.0, 0.0, 3.0),
        bevy_landmass::Vec3::new(1.0, 0.0, 3.0),
        bevy_landmass::Vec3::new(2.0, 0.0, 4.0),
        bevy_landmass::Vec3::new(1.0, 0.0, 4.0),
      ],
      polygons: vec![
        vec![0, 1, 2, 3],
        vec![3, 2, 4, 5],
        vec![5, 4, 6, 7],
      ],
    }.validate().expect("is valid"));
  nav_meshes.insert(nav_mesh_handle, NavMesh(nav_mesh));

  commands.spawn(TransformBundle {
    local: Transform::from_translation(Vec3::new(1.5, 0.0, 1.5)),
    ..Default::default()
  }).insert(AgentBundle {
    agent: Agent {
      radius: 0.5,
      max_velocity: 1.0,
    },
    archipelago_ref: ArchipelagoRef(archipelago_id),
    target: AgentTarget::Point(Vec3::new(1.5, 0.0, 3.5)),
    velocity: Default::default(),
    state: Default::default(),
    desired_velocity: Default::default(),
  });
}

fn print_desired_velocity(query: Query<(Entity, &AgentDesiredVelocity)>) {
  for (entity, desired_velocity) in query.iter() {
    println!(
      "entity={:?}, desired_velocity={}",
      entity,
      desired_velocity.velocity());
  }
}

fn quit(mut exit: EventWriter<AppExit>) {
  // Quit so doctests pass.
  exit.send(AppExit);
}

License

License under either of

• Apache License, Version 2.0 (LICENSE-APACHE or http://www.apache.org/licenses/LICENSE-2.0)
• MIT license (LICENSE-MIT or http://opensource.org/licenses/MIT)

at your option.

Contribution

Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in the work by you, as defined in the Apache-2.0 license, shall be dual licensed as above, without any additional terms or conditions.