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bevy/examples/2d/custom_gltf_vertex_attribute.rs
Joona Aalto 25bfa80e60
Migrate cameras to required components ()
# Objective

Yet another PR for migrating stuff to required components. This time,
cameras!

## Solution

As per the [selected
proposal](https://hackmd.io/tsYID4CGRiWxzsgawzxG_g#Combined-Proposal-1-Selected),
deprecate `Camera2dBundle` and `Camera3dBundle` in favor of `Camera2d`
and `Camera3d`.

Adding a `Camera` without `Camera2d` or `Camera3d` now logs a warning,
as suggested by Cart [on
Discord](https://discord.com/channels/691052431525675048/1264881140007702558/1291506402832945273).
I would personally like cameras to work a bit differently and be split
into a few more components, to avoid some footguns and confusing
semantics, but that is more controversial, and shouldn't block this core
migration.

## Testing

I ran a few 2D and 3D examples, and tried cameras with and without
render graphs.

---

## Migration Guide

`Camera2dBundle` and `Camera3dBundle` have been deprecated in favor of
`Camera2d` and `Camera3d`. Inserting them will now also insert the other
components required by them automatically.
2024-10-05 01:59:52 +00:00

93 lines
3 KiB
Rust

//! Renders a glTF mesh in 2D with a custom vertex attribute.
use bevy::{
gltf::GltfPlugin,
prelude::*,
reflect::TypePath,
render::{
mesh::{MeshVertexAttribute, MeshVertexBufferLayoutRef},
render_resource::*,
},
sprite::{Material2d, Material2dKey, Material2dPlugin},
};
/// This example uses a shader source file from the assets subdirectory
const SHADER_ASSET_PATH: &str = "shaders/custom_gltf_2d.wgsl";
/// This vertex attribute supplies barycentric coordinates for each triangle.
///
/// Each component of the vector corresponds to one corner of a triangle. It's
/// equal to 1.0 in that corner and 0.0 in the other two. Hence, its value in
/// the fragment shader indicates proximity to a corner or the opposite edge.
const ATTRIBUTE_BARYCENTRIC: MeshVertexAttribute =
MeshVertexAttribute::new("Barycentric", 2137464976, VertexFormat::Float32x3);
fn main() {
App::new()
.insert_resource(AmbientLight {
color: Color::WHITE,
brightness: 1.0 / 5.0f32,
})
.add_plugins((
DefaultPlugins.set(
GltfPlugin::default()
// Map a custom glTF attribute name to a `MeshVertexAttribute`.
.add_custom_vertex_attribute("_BARYCENTRIC", ATTRIBUTE_BARYCENTRIC),
),
Material2dPlugin::<CustomMaterial>::default(),
))
.add_systems(Startup, setup)
.run();
}
fn setup(
mut commands: Commands,
asset_server: Res<AssetServer>,
mut materials: ResMut<Assets<CustomMaterial>>,
) {
// Add a mesh loaded from a glTF file. This mesh has data for `ATTRIBUTE_BARYCENTRIC`.
let mesh = asset_server.load(
GltfAssetLabel::Primitive {
mesh: 0,
primitive: 0,
}
.from_asset("models/barycentric/barycentric.gltf"),
);
commands.spawn((
Mesh2d(mesh),
MeshMaterial2d(materials.add(CustomMaterial {})),
Transform::from_scale(150.0 * Vec3::ONE),
));
// Add a camera
commands.spawn(Camera2d);
}
/// This custom material uses barycentric coordinates from
/// `ATTRIBUTE_BARYCENTRIC` to shade a white border around each triangle. The
/// thickness of the border is animated using the global time shader uniform.
#[derive(Asset, TypePath, AsBindGroup, Debug, Clone)]
struct CustomMaterial {}
impl Material2d for CustomMaterial {
fn vertex_shader() -> ShaderRef {
SHADER_ASSET_PATH.into()
}
fn fragment_shader() -> ShaderRef {
SHADER_ASSET_PATH.into()
}
fn specialize(
descriptor: &mut RenderPipelineDescriptor,
layout: &MeshVertexBufferLayoutRef,
_key: Material2dKey<Self>,
) -> Result<(), SpecializedMeshPipelineError> {
let vertex_layout = layout.0.get_layout(&[
Mesh::ATTRIBUTE_POSITION.at_shader_location(0),
Mesh::ATTRIBUTE_COLOR.at_shader_location(1),
ATTRIBUTE_BARYCENTRIC.at_shader_location(2),
])?;
descriptor.vertex.buffers = vec![vertex_layout];
Ok(())
}
}