Custom mesh loader for collision shape

[lattice0]

Following #5683, I tried

extern crate bevy;
extern crate bevy_rapier3d;
use bevy::{
    diagnostic::{FrameTimeDiagnosticsPlugin, LogDiagnosticsPlugin},
    prelude::*,
};
use bevy_rapier3d::prelude::*;

fn main() {
    App::new()
        .add_plugins(DefaultPlugins)
        .add_plugin(RapierPhysicsPlugin::<NoUserData>::default())
        .add_plugin(LogDiagnosticsPlugin::default())
        .add_plugin(FrameTimeDiagnosticsPlugin::default())
        .add_plugin(RapierDebugRenderPlugin::default())
        .add_startup_system(setup)
        .add_startup_system(setup_graphics)
        .add_startup_system(check_assets_ready)
        .run();
}

struct AssetsLoading(Vec<HandleUntyped>);

fn setup(server: Res<AssetServer>, mut loading: ResMut<AssetsLoading>) {
    let x_shape: Handle<Mesh> = server.load("quad.gltf#Mesh0/Primitive0");
    loading.0.push(x_shape.clone_untyped());
}

fn check_assets_ready(
    mut commands: Commands,
    server: Res<AssetServer>,
    mut meshes: ResMut<Assets<Mesh>>,
    mut materials: ResMut<Assets<StandardMaterial>>,
    loading: Res<AssetsLoading>,
) {
    use bevy::asset::LoadState;

    match server.get_group_load_state(loading.0.iter().map(|h| h.id)) {
        LoadState::Failed => {
            // one of our assets had an error
        }
        LoadState::Loaded => setup_physics(commands, server, meshes, materials),
        _ => {
            // NotLoaded/Loading: not fully ready yet
        }
    }
}

fn setup_graphics(mut commands: Commands) {
    commands.spawn_bundle(Camera3dBundle {
        camera: Camera {
            priority: 1,
            ..Default::default()
        },
        transform: Transform::from_xyz(-0.1, 3.0, 5.0).looking_at(Vec3::ZERO, Vec3::Y),
        ..Default::default()
    });
}

fn setup_physics(
    mut commands: Commands,
    asset_server: Res<AssetServer>,
    mut meshes: ResMut<Assets<Mesh>>,
    mut materials: ResMut<Assets<StandardMaterial>>,
) {
    //Floor
    commands
        .spawn_bundle(PbrBundle {
            mesh: meshes.add(Mesh::from(shape::Plane { size: 100.0 })),
            material: materials.add(Color::rgb(0.3, 0.5, 0.3).into()),
            ..default()
        })
        .insert(Collider::cuboid(100.0, 0.1, 100.0));
    commands.spawn_bundle(PointLightBundle {
        point_light: PointLight {
            intensity: 1500.0,
            shadows_enabled: true,
            ..default()
        },
        transform: Transform::from_xyz(4.0, 8.0, 4.0),
        ..default()
    });

    //Drone
    let x_shape: Handle<Mesh> = asset_server.load("quad.gltf#Mesh0/Primitive0");

    let m = &meshes.get(&x_shape);
    let x_shape = Collider::from_bevy_mesh(m.unwrap(), &ComputedColliderShape::TriMesh).unwrap();
    commands
        .spawn()
        .insert(RigidBody::Dynamic)
        .insert(x_shape)
        .insert(Restitution::coefficient(0.7))
        .insert_bundle(TransformBundle::from(Transform::from_xyz(0.0, 4.0, 0.0)));
}

but I get

thread 'Compute Task Pool (1)' panicked at 'Resource requested by quad::check_assets_ready does not exist: quad::AssetsLoading', /home/user/.cargo/registry/src/github.com-1ecc6299db9ec823/bevy_ecs-0.8.0/src/system/system_param.rs:349:17

what is wrong with I'md oing?

[rparrett]

The AssetsLoading Resource needs to be initialized/registered before it can be used. One way to do this is to derive the Default trait and call app.init_resource in fn main.

#[derive(Default)]
struct AssetsLoading(Vec<HandleUntyped>);

App::new()
    .init_resource::<AssetsLoading>()

Your next issue will be that check_assets_ready needs to be a normal system. Right now it is only running once, but it needs to be running all the time to keep checking if the asset is ready. So use .add_system instead of .add_startup_system for that system.

After that, you should be seeing some pretty colors and things getting spawned. Too many things being spawned, in fact! Because check_assets_ready is now a normal system, it's calling setup_physics every frame.

You'll want to use another Resource, Local, or State to keep track of whether the "physics has been setup." so you're only doing that once.

Using a Resource (e.g. struct PhysicsSetup(bool)) would be the quick an dirty way, but I'd encourage you to look into State soon. Bevy apps often have an AppState::Loading where these systems run before advancing to an AppStage::Menu or AppState::Playing or whatever.

There's also a great plugin called bevy_asset_loader that takes some of the hassle out of tracking loading assets and advancing to your app's next State.

[lattice0]

Ok I modified it and did

extern crate bevy;
extern crate bevy_rapier3d;
use std::sync::atomic::AtomicBool;

use bevy::{
    diagnostic::{FrameTimeDiagnosticsPlugin, LogDiagnosticsPlugin},
    prelude::*,
};
use bevy_rapier3d::prelude::*;

fn main() {
    App::new()
        .add_plugins(DefaultPlugins)
        .add_plugin(RapierPhysicsPlugin::<NoUserData>::default())
        .add_plugin(LogDiagnosticsPlugin::default())
        .add_plugin(FrameTimeDiagnosticsPlugin::default())
        .add_plugin(RapierDebugRenderPlugin::default())
        .add_startup_system(setup)
        .add_startup_system(setup_graphics)
        .add_system(check_assets_ready)
        .init_resource::<AssetsLoading>()
        .run();
}

#[derive(Default)]
struct AssetsLoading(Vec<HandleUntyped>);

fn setup(server: Res<AssetServer>, mut loading: ResMut<AssetsLoading>) {
    let x_shape: Handle<Mesh> = server.load("quad.gltf#Mesh0/Primitive0");
    loading.0.push(x_shape.clone_untyped());
}

fn check_assets_ready(
    commands: Commands,
    server: Res<AssetServer>,
    meshes: ResMut<Assets<Mesh>>,
    materials: ResMut<Assets<StandardMaterial>>,
    loading: Res<AssetsLoading>,
) {
    use bevy::asset::LoadState;
    static SETUP_PHYSICS_CALLED: AtomicBool = AtomicBool::new(false);
    match server.get_group_load_state(loading.0.iter().map(|h| h.id)) {
        LoadState::Failed => {
            // one of our assets had an error
        }
        LoadState::Loaded => {
            if !SETUP_PHYSICS_CALLED.load(std::sync::atomic::Ordering::Relaxed) {
                setup_physics(commands, server, meshes, materials);
                SETUP_PHYSICS_CALLED.store(true, std::sync::atomic::Ordering::Relaxed);
            }
        }
        _ => {
            // NotLoaded/Loading: not fully ready yet
        }
    }
}

fn setup_graphics(mut commands: Commands) {
    commands.spawn_bundle(Camera3dBundle {
        camera: Camera {
            priority: 1,
            ..Default::default()
        },
        transform: Transform::from_xyz(-0.1, 3.0, 5.0).looking_at(Vec3::ZERO, Vec3::Y),
        ..Default::default()
    });
}

fn setup_physics(
    mut commands: Commands,
    asset_server: Res<AssetServer>,
    mut meshes: ResMut<Assets<Mesh>>,
    mut materials: ResMut<Assets<StandardMaterial>>,
) {
    //Floor
    commands
        .spawn_bundle(PbrBundle {
            mesh: meshes.add(Mesh::from(shape::Plane { size: 100.0 })),
            material: materials.add(Color::rgb(0.3, 0.5, 0.3).into()),
            ..default()
        })
        .insert(Collider::cuboid(100.0, 0.1, 100.0));
    commands.spawn_bundle(PointLightBundle {
        point_light: PointLight {
            intensity: 1500.0,
            shadows_enabled: true,
            ..default()
        },
        transform: Transform::from_xyz(4.0, 8.0, 4.0),
        ..default()
    });

    //Drone
    let x_shape: Handle<Mesh> = asset_server.load("quad.gltf#Mesh0/Primitive0");

    let m = &meshes.get(&x_shape);
    let x_shape = Collider::from_bevy_mesh(m.unwrap(), &ComputedColliderShape::TriMesh).unwrap();
    commands
        .spawn()
        .insert(RigidBody::Dynamic)
        .insert(x_shape)
        .insert(Restitution::coefficient(0.7))
        .insert_bundle(TransformBundle::from(Transform::from_xyz(0.0, 4.0, 0.0)));
}

I'll later look at states.

Problem is that the object is not an X shape like I saved in Blender:

I think it has to do with the Triangles here:

let x_shape = Collider::from_bevy_mesh(m.unwrap(), &ComputedColliderShape::TriMesh).unwrap();

I don't know what is happening for it to interpret the x shape as this. Or maybe I'm loading the wrong primitive with quad.gltf#Mesh0/Primitive0?

[rparrett]

Could be. For example, this is what I get when I just extrude 4 faces of the default blender cube:

[lattice0]

That's sad, I don't know how to proceed. Is this a bug or I'm using something wrong?

Do you know a way of drawing 2 cuboids in an X shape as a Mesh? I tried this first but couldn't make them be a single object. However I suspect that it would have the same problem because it would be a mesh for the same shape.

[rparrett]

It looks like it's working to me, but you would need to rework your gltf so that there is only one resulting mesh.

If you added two stretched cubes in blender, you can add a boolean (union) modifier to combine them. (Be sure to "apply" that modifier). If you scaled the cubes in blender, you might also need to "apply" the scale as well.

Or you could use one cube as I did, and extrude 4 of its faces to make the X shape.

[lattice0]

Thanks, I was able to do it with scale and boolean