bevy/examples/tools/scene_viewer/main.rs
Joona Aalto 54006b107b
Migrate meshes and materials to required components (#15524)
# Objective

A big step in the migration to required components: meshes and
materials!

## Solution

As per the [selected
proposal](https://hackmd.io/@bevy/required_components/%2Fj9-PnF-2QKK0on1KQ29UWQ):

- Deprecate `MaterialMesh2dBundle`, `MaterialMeshBundle`, and
`PbrBundle`.
- Add `Mesh2d` and `Mesh3d` components, which wrap a `Handle<Mesh>`.
- Add `MeshMaterial2d<M: Material2d>` and `MeshMaterial3d<M: Material>`,
which wrap a `Handle<M>`.
- Meshes *without* a mesh material should be rendered with a default
material. The existence of a material is determined by
`HasMaterial2d`/`HasMaterial3d`, which is required by
`MeshMaterial2d`/`MeshMaterial3d`. This gets around problems with the
generics.

Previously:

```rust
commands.spawn(MaterialMesh2dBundle {
    mesh: meshes.add(Circle::new(100.0)).into(),
    material: materials.add(Color::srgb(7.5, 0.0, 7.5)),
    transform: Transform::from_translation(Vec3::new(-200., 0., 0.)),
    ..default()
});
```

Now:

```rust
commands.spawn((
    Mesh2d(meshes.add(Circle::new(100.0))),
    MeshMaterial2d(materials.add(Color::srgb(7.5, 0.0, 7.5))),
    Transform::from_translation(Vec3::new(-200., 0., 0.)),
));
```

If the mesh material is missing, previously nothing was rendered. Now,
it renders a white default `ColorMaterial` in 2D and a
`StandardMaterial` in 3D (this can be overridden). Below, only every
other entity has a material:

![Näyttökuva 2024-09-29
181746](https://github.com/user-attachments/assets/5c8be029-d2fe-4b8c-ae89-17a72ff82c9a)

![Näyttökuva 2024-09-29
181918](https://github.com/user-attachments/assets/58adbc55-5a1e-4c7d-a2c7-ed456227b909)

Why white? This is still open for discussion, but I think white makes
sense for a *default* material, while *invalid* asset handles pointing
to nothing should have something like a pink material to indicate that
something is broken (I don't handle that in this PR yet). This is kind
of a mix of Godot and Unity: Godot just renders a white material for
non-existent materials, while Unity renders nothing when no materials
exist, but renders pink for invalid materials. I can also change the
default material to pink if that is preferable though.

## Testing

I ran some 2D and 3D examples to test if anything changed visually. I
have not tested all examples or features yet however. If anyone wants to
test more extensively, it would be appreciated!

## Implementation Notes

- The relationship between `bevy_render` and `bevy_pbr` is weird here.
`bevy_render` needs `Mesh3d` for its own systems, but `bevy_pbr` has all
of the material logic, and `bevy_render` doesn't depend on it. I feel
like the two crates should be refactored in some way, but I think that's
out of scope for this PR.
- I didn't migrate meshlets to required components yet. That can
probably be done in a follow-up, as this is already a huge PR.
- It is becoming increasingly clear to me that we really, *really* want
to disallow raw asset handles as components. They caused me a *ton* of
headache here already, and it took me a long time to find every place
that queried for them or inserted them directly on entities, since there
were no compiler errors for it. If we don't remove the `Component`
derive, I expect raw asset handles to be a *huge* footgun for users as
we transition to wrapper components, especially as handles as components
have been the norm so far. I personally consider this to be a blocker
for 0.15: we need to migrate to wrapper components for asset handles
everywhere, and remove the `Component` derive. Also see
https://github.com/bevyengine/bevy/issues/14124.

---

## Migration Guide

Asset handles for meshes and mesh materials must now be wrapped in the
`Mesh2d` and `MeshMaterial2d` or `Mesh3d` and `MeshMaterial3d`
components for 2D and 3D respectively. Raw handles as components no
longer render meshes.

Additionally, `MaterialMesh2dBundle`, `MaterialMeshBundle`, and
`PbrBundle` have been deprecated. Instead, use the mesh and material
components directly.

Previously:

```rust
commands.spawn(MaterialMesh2dBundle {
    mesh: meshes.add(Circle::new(100.0)).into(),
    material: materials.add(Color::srgb(7.5, 0.0, 7.5)),
    transform: Transform::from_translation(Vec3::new(-200., 0., 0.)),
    ..default()
});
```

Now:

```rust
commands.spawn((
    Mesh2d(meshes.add(Circle::new(100.0))),
    MeshMaterial2d(materials.add(Color::srgb(7.5, 0.0, 7.5))),
    Transform::from_translation(Vec3::new(-200., 0., 0.)),
));
```

If the mesh material is missing, a white default material is now used.
Previously, nothing was rendered if the material was missing.

The `WithMesh2d` and `WithMesh3d` query filter type aliases have also
been removed. Simply use `With<Mesh2d>` or `With<Mesh3d>`.

---------

Co-authored-by: Tim Blackbird <justthecooldude@gmail.com>
Co-authored-by: Carter Anderson <mcanders1@gmail.com>
2024-10-01 21:33:17 +00:00

165 lines
5.7 KiB
Rust

//! A simple glTF scene viewer made with Bevy.
//!
//! Just run `cargo run --release --example scene_viewer /path/to/model.gltf`,
//! replacing the path as appropriate.
//! In case of multiple scenes, you can select which to display by adapting the file path: `/path/to/model.gltf#Scene1`.
//! With no arguments it will load the `FlightHelmet` glTF model from the repository assets subdirectory.
//!
//! If you want to hot reload asset changes, enable the `file_watcher` cargo feature.
use bevy::{
math::Vec3A,
prelude::*,
render::primitives::{Aabb, Sphere},
};
#[path = "../../helpers/camera_controller.rs"]
mod camera_controller;
#[cfg(feature = "animation")]
mod animation_plugin;
mod morph_viewer_plugin;
mod scene_viewer_plugin;
use camera_controller::{CameraController, CameraControllerPlugin};
use morph_viewer_plugin::MorphViewerPlugin;
use scene_viewer_plugin::{SceneHandle, SceneViewerPlugin};
fn main() {
let mut app = App::new();
app.add_plugins((
DefaultPlugins
.set(WindowPlugin {
primary_window: Some(Window {
title: "bevy scene viewer".to_string(),
..default()
}),
..default()
})
.set(AssetPlugin {
file_path: std::env::var("CARGO_MANIFEST_DIR").unwrap_or_else(|_| ".".to_string()),
..default()
}),
CameraControllerPlugin,
SceneViewerPlugin,
MorphViewerPlugin,
))
.add_systems(Startup, setup)
.add_systems(PreUpdate, setup_scene_after_load);
#[cfg(feature = "animation")]
app.add_plugins(animation_plugin::AnimationManipulationPlugin);
app.run();
}
fn parse_scene(scene_path: String) -> (String, usize) {
if scene_path.contains('#') {
let gltf_and_scene = scene_path.split('#').collect::<Vec<_>>();
if let Some((last, path)) = gltf_and_scene.split_last() {
if let Some(index) = last
.strip_prefix("Scene")
.and_then(|index| index.parse::<usize>().ok())
{
return (path.join("#"), index);
}
}
}
(scene_path, 0)
}
fn setup(mut commands: Commands, asset_server: Res<AssetServer>) {
let scene_path = std::env::args()
.nth(1)
.unwrap_or_else(|| "assets/models/FlightHelmet/FlightHelmet.gltf".to_string());
info!("Loading {}", scene_path);
let (file_path, scene_index) = parse_scene(scene_path);
commands.insert_resource(SceneHandle::new(asset_server.load(file_path), scene_index));
}
fn setup_scene_after_load(
mut commands: Commands,
mut setup: Local<bool>,
mut scene_handle: ResMut<SceneHandle>,
asset_server: Res<AssetServer>,
meshes: Query<(&GlobalTransform, Option<&Aabb>), With<Mesh3d>>,
) {
if scene_handle.is_loaded && !*setup {
*setup = true;
// Find an approximate bounding box of the scene from its meshes
if meshes.iter().any(|(_, maybe_aabb)| maybe_aabb.is_none()) {
return;
}
let mut min = Vec3A::splat(f32::MAX);
let mut max = Vec3A::splat(f32::MIN);
for (transform, maybe_aabb) in &meshes {
let aabb = maybe_aabb.unwrap();
// If the Aabb had not been rotated, applying the non-uniform scale would produce the
// correct bounds. However, it could very well be rotated and so we first convert to
// a Sphere, and then back to an Aabb to find the conservative min and max points.
let sphere = Sphere {
center: Vec3A::from(transform.transform_point(Vec3::from(aabb.center))),
radius: transform.radius_vec3a(aabb.half_extents),
};
let aabb = Aabb::from(sphere);
min = min.min(aabb.min());
max = max.max(aabb.max());
}
let size = (max - min).length();
let aabb = Aabb::from_min_max(Vec3::from(min), Vec3::from(max));
info!("Spawning a controllable 3D perspective camera");
let mut projection = PerspectiveProjection::default();
projection.far = projection.far.max(size * 10.0);
let walk_speed = size * 3.0;
let camera_controller = CameraController {
walk_speed,
run_speed: 3.0 * walk_speed,
..default()
};
// Display the controls of the scene viewer
info!("{}", camera_controller);
info!("{}", *scene_handle);
commands.spawn((
Camera3dBundle {
projection: projection.into(),
transform: Transform::from_translation(
Vec3::from(aabb.center) + size * Vec3::new(0.5, 0.25, 0.5),
)
.looking_at(Vec3::from(aabb.center), Vec3::Y),
camera: Camera {
is_active: false,
..default()
},
..default()
},
EnvironmentMapLight {
diffuse_map: asset_server
.load("assets/environment_maps/pisa_diffuse_rgb9e5_zstd.ktx2"),
specular_map: asset_server
.load("assets/environment_maps/pisa_specular_rgb9e5_zstd.ktx2"),
intensity: 150.0,
..default()
},
camera_controller,
));
// Spawn a default light if the scene does not have one
if !scene_handle.has_light {
info!("Spawning a directional light");
commands.spawn((
DirectionalLight::default(),
Transform::from_xyz(1.0, 1.0, 0.0).looking_at(Vec3::ZERO, Vec3::Y),
));
scene_handle.has_light = true;
}
}
}