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bevy/examples/3d/lines.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

129 lines
3.8 KiB
Rust

//! Create a custom material to draw basic lines in 3D
use bevy::{
pbr::{MaterialPipeline, MaterialPipelineKey},
prelude::*,
reflect::TypePath,
render::{
mesh::{MeshVertexBufferLayoutRef, PrimitiveTopology},
render_asset::RenderAssetUsages,
render_resource::{
AsBindGroup, PolygonMode, RenderPipelineDescriptor, ShaderRef,
SpecializedMeshPipelineError,
},
},
};
/// This example uses a shader source file from the assets subdirectory
const SHADER_ASSET_PATH: &str = "shaders/line_material.wgsl";
fn main() {
App::new()
.add_plugins((DefaultPlugins, MaterialPlugin::<LineMaterial>::default()))
.add_systems(Startup, setup)
.run();
}
fn setup(
mut commands: Commands,
mut meshes: ResMut<Assets<Mesh>>,
mut materials: ResMut<Assets<LineMaterial>>,
) {
// Spawn a list of lines with start and end points for each lines
commands.spawn((
Mesh3d(meshes.add(LineList {
lines: vec![
(Vec3::ZERO, Vec3::new(1.0, 1.0, 0.0)),
(Vec3::new(1.0, 1.0, 0.0), Vec3::new(1.0, 0.0, 0.0)),
],
})),
MeshMaterial3d(materials.add(LineMaterial {
color: LinearRgba::GREEN,
})),
Transform::from_xyz(-1.5, 0.0, 0.0),
));
// Spawn a line strip that goes from point to point
commands.spawn((
Mesh3d(meshes.add(LineStrip {
points: vec![
Vec3::ZERO,
Vec3::new(1.0, 1.0, 0.0),
Vec3::new(1.0, 0.0, 0.0),
],
})),
MeshMaterial3d(materials.add(LineMaterial {
color: LinearRgba::BLUE,
})),
Transform::from_xyz(0.5, 0.0, 0.0),
));
// camera
commands.spawn((
Camera3d::default(),
Transform::from_xyz(-2.0, 2.5, 5.0).looking_at(Vec3::ZERO, Vec3::Y),
));
}
#[derive(Asset, TypePath, Default, AsBindGroup, Debug, Clone)]
struct LineMaterial {
#[uniform(0)]
color: LinearRgba,
}
impl Material for LineMaterial {
fn fragment_shader() -> ShaderRef {
SHADER_ASSET_PATH.into()
}
fn specialize(
_pipeline: &MaterialPipeline<Self>,
descriptor: &mut RenderPipelineDescriptor,
_layout: &MeshVertexBufferLayoutRef,
_key: MaterialPipelineKey<Self>,
) -> Result<(), SpecializedMeshPipelineError> {
// This is the important part to tell bevy to render this material as a line between vertices
descriptor.primitive.polygon_mode = PolygonMode::Line;
Ok(())
}
}
/// A list of lines with a start and end position
#[derive(Debug, Clone)]
struct LineList {
lines: Vec<(Vec3, Vec3)>,
}
impl From<LineList> for Mesh {
fn from(line: LineList) -> Self {
let vertices: Vec<_> = line.lines.into_iter().flat_map(|(a, b)| [a, b]).collect();
Mesh::new(
// This tells wgpu that the positions are list of lines
// where every pair is a start and end point
PrimitiveTopology::LineList,
RenderAssetUsages::RENDER_WORLD,
)
// Add the vertices positions as an attribute
.with_inserted_attribute(Mesh::ATTRIBUTE_POSITION, vertices)
}
}
/// A list of points that will have a line drawn between each consecutive points
#[derive(Debug, Clone)]
struct LineStrip {
points: Vec<Vec3>,
}
impl From<LineStrip> for Mesh {
fn from(line: LineStrip) -> Self {
Mesh::new(
// This tells wgpu that the positions are a list of points
// where a line will be drawn between each consecutive point
PrimitiveTopology::LineStrip,
RenderAssetUsages::RENDER_WORLD,
)
// Add the point positions as an attribute
.with_inserted_attribute(Mesh::ATTRIBUTE_POSITION, line.points)
}
}