bevy/examples/shader/custom_vertex_attribute.rs
Joona Aalto 25bfa80e60
Migrate cameras to required components (#15641)
# 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

89 lines
2.7 KiB
Rust

//! A shader that reads a mesh's custom vertex attribute.
use bevy::{
pbr::{MaterialPipeline, MaterialPipelineKey},
prelude::*,
reflect::TypePath,
render::{
mesh::{MeshVertexAttribute, MeshVertexBufferLayoutRef},
render_resource::{
AsBindGroup, RenderPipelineDescriptor, ShaderRef, SpecializedMeshPipelineError,
VertexFormat,
},
},
};
/// This example uses a shader source file from the assets subdirectory
const SHADER_ASSET_PATH: &str = "shaders/custom_vertex_attribute.wgsl";
fn main() {
App::new()
.add_plugins((DefaultPlugins, MaterialPlugin::<CustomMaterial>::default()))
.add_systems(Startup, setup)
.run();
}
// A "high" random id should be used for custom attributes to ensure consistent sorting and avoid collisions with other attributes.
// See the MeshVertexAttribute docs for more info.
const ATTRIBUTE_BLEND_COLOR: MeshVertexAttribute =
MeshVertexAttribute::new("BlendColor", 988540917, VertexFormat::Float32x4);
/// set up a simple 3D scene
fn setup(
mut commands: Commands,
mut meshes: ResMut<Assets<Mesh>>,
mut materials: ResMut<Assets<CustomMaterial>>,
) {
let mesh = Mesh::from(Cuboid::default())
// Sets the custom attribute
.with_inserted_attribute(
ATTRIBUTE_BLEND_COLOR,
// The cube mesh has 24 vertices (6 faces, 4 vertices per face), so we insert one BlendColor for each
vec![[1.0, 0.0, 0.0, 1.0]; 24],
);
// cube
commands.spawn((
Mesh3d(meshes.add(mesh)),
MeshMaterial3d(materials.add(CustomMaterial {
color: LinearRgba::WHITE,
})),
Transform::from_xyz(0.0, 0.5, 0.0),
));
// camera
commands.spawn((
Camera3d::default(),
Transform::from_xyz(-2.0, 2.5, 5.0).looking_at(Vec3::ZERO, Vec3::Y),
));
}
// This is the struct that will be passed to your shader
#[derive(Asset, TypePath, AsBindGroup, Debug, Clone)]
struct CustomMaterial {
#[uniform(0)]
color: LinearRgba,
}
impl Material for CustomMaterial {
fn vertex_shader() -> ShaderRef {
SHADER_ASSET_PATH.into()
}
fn fragment_shader() -> ShaderRef {
SHADER_ASSET_PATH.into()
}
fn specialize(
_pipeline: &MaterialPipeline<Self>,
descriptor: &mut RenderPipelineDescriptor,
layout: &MeshVertexBufferLayoutRef,
_key: MaterialPipelineKey<Self>,
) -> Result<(), SpecializedMeshPipelineError> {
let vertex_layout = layout.0.get_layout(&[
Mesh::ATTRIBUTE_POSITION.at_shader_location(0),
ATTRIBUTE_BLEND_COLOR.at_shader_location(1),
])?;
descriptor.vertex.buffers = vec![vertex_layout];
Ok(())
}
}