bevy/examples/2d/wireframe_2d.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

147 lines
4.6 KiB
Rust

//! Showcases wireframe rendering for 2d meshes.
//!
//! Wireframes currently do not work when using webgl or webgpu.
//! Supported platforms:
//! - DX12
//! - Vulkan
//! - Metal
//!
//! This is a native only feature.
use bevy::{
color::palettes::basic::{GREEN, RED, WHITE},
prelude::*,
render::{
render_resource::WgpuFeatures,
settings::{RenderCreation, WgpuSettings},
RenderPlugin,
},
sprite::{NoWireframe2d, Wireframe2d, Wireframe2dColor, Wireframe2dConfig, Wireframe2dPlugin},
};
fn main() {
App::new()
.add_plugins((
DefaultPlugins.set(RenderPlugin {
render_creation: RenderCreation::Automatic(WgpuSettings {
// WARN this is a native only feature. It will not work with webgl or webgpu
features: WgpuFeatures::POLYGON_MODE_LINE,
..default()
}),
..default()
}),
// You need to add this plugin to enable wireframe rendering
Wireframe2dPlugin,
))
// Wireframes can be configured with this resource. This can be changed at runtime.
.insert_resource(Wireframe2dConfig {
// The global wireframe config enables drawing of wireframes on every mesh,
// except those with `NoWireframe2d`. Meshes with `Wireframe2d` will always have a wireframe,
// regardless of the global configuration.
global: true,
// Controls the default color of all wireframes. Used as the default color for global wireframes.
// Can be changed per mesh using the `Wireframe2dColor` component.
default_color: WHITE.into(),
})
.add_systems(Startup, setup)
.add_systems(Update, update_colors)
.run();
}
/// Set up a simple 3D scene
fn setup(
mut commands: Commands,
mut meshes: ResMut<Assets<Mesh>>,
mut materials: ResMut<Assets<ColorMaterial>>,
) {
// Triangle: Never renders a wireframe
commands.spawn((
Mesh2d(meshes.add(Triangle2d::new(
Vec2::new(0.0, 50.0),
Vec2::new(-50.0, -50.0),
Vec2::new(50.0, -50.0),
))),
MeshMaterial2d(materials.add(Color::BLACK)),
Transform::from_xyz(-150.0, 0.0, 0.0),
NoWireframe2d,
));
// Rectangle: Follows global wireframe setting
commands.spawn((
Mesh2d(meshes.add(Rectangle::new(100.0, 100.0))),
MeshMaterial2d(materials.add(Color::BLACK)),
Transform::from_xyz(0.0, 0.0, 0.0),
));
// Circle: Always renders a wireframe
commands.spawn((
Mesh2d(meshes.add(Circle::new(50.0))),
MeshMaterial2d(materials.add(Color::BLACK)),
Transform::from_xyz(150.0, 0.0, 0.0),
Wireframe2d,
// This lets you configure the wireframe color of this entity.
// If not set, this will use the color in `WireframeConfig`
Wireframe2dColor {
color: GREEN.into(),
},
));
// Camera
commands.spawn(Camera2dBundle::default());
// Text used to show controls
commands.spawn(
TextBundle::from_section("", TextStyle::default()).with_style(Style {
position_type: PositionType::Absolute,
top: Val::Px(12.0),
left: Val::Px(12.0),
..default()
}),
);
}
/// This system lets you toggle various wireframe settings
fn update_colors(
keyboard_input: Res<ButtonInput<KeyCode>>,
mut config: ResMut<Wireframe2dConfig>,
mut wireframe_colors: Query<&mut Wireframe2dColor>,
mut text: Query<&mut Text>,
) {
text.single_mut().sections[0].value = format!(
"Controls
---------------
Z - Toggle global
X - Change global color
C - Change color of the circle wireframe
Wireframe2dConfig
-------------
Global: {}
Color: {:?}",
config.global,
config.default_color.to_srgba(),
);
// Toggle showing a wireframe on all meshes
if keyboard_input.just_pressed(KeyCode::KeyZ) {
config.global = !config.global;
}
// Toggle the global wireframe color
if keyboard_input.just_pressed(KeyCode::KeyX) {
config.default_color = if config.default_color == WHITE.into() {
RED.into()
} else {
WHITE.into()
};
}
// Toggle the color of a wireframe using `Wireframe2dColor` and not the global color
if keyboard_input.just_pressed(KeyCode::KeyC) {
for mut color in &mut wireframe_colors {
color.color = if color.color == GREEN.into() {
RED.into()
} else {
GREEN.into()
};
}
}
}