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bevy/examples/3d/reflection_probes.rs
Carter Anderson 015f2c69ca
Merge Style properties into Node. Use ComputedNode for computed properties. ()
# Objective

Continue improving the user experience of our UI Node API in the
direction specified by [Bevy's Next Generation Scene / UI
System](https://github.com/bevyengine/bevy/discussions/14437)

## Solution

As specified in the document above, merge `Style` fields into `Node`,
and move "computed Node fields" into `ComputedNode` (I chose this name
over something like `ComputedNodeLayout` because it currently contains
more than just layout info. If we want to break this up / rename these
concepts, lets do that in a separate PR). `Style` has been removed.

This accomplishes a number of goals:

## Ergonomics wins

Specifying both `Node` and `Style` is now no longer required for
non-default styles

Before:
```rust
commands.spawn((
    Node::default(),
    Style {
        width:  Val::Px(100.),
        ..default()
    },
));
```

After:

```rust
commands.spawn(Node {
    width:  Val::Px(100.),
    ..default()
});
```

## Conceptual clarity

`Style` was never a comprehensive "style sheet". It only defined "core"
style properties that all `Nodes` shared. Any "styled property" that
couldn't fit that mold had to be in a separate component. A "real" style
system would style properties _across_ components (`Node`, `Button`,
etc). We have plans to build a true style system (see the doc linked
above).

By moving the `Style` fields to `Node`, we fully embrace `Node` as the
driving concept and remove the "style system" confusion.

## Next Steps

* Consider identifying and splitting out "style properties that aren't
core to Node". This should not happen for Bevy 0.15.

---

## Migration Guide

Move any fields set on `Style` into `Node` and replace all `Style`
component usage with `Node`.

Before:
```rust
commands.spawn((
    Node::default(),
    Style {
        width:  Val::Px(100.),
        ..default()
    },
));
```

After:

```rust
commands.spawn(Node {
    width:  Val::Px(100.),
    ..default()
});
```

For any usage of the "computed node properties" that used to live on
`Node`, use `ComputedNode` instead:

Before:
```rust
fn system(nodes: Query<&Node>) {
    for node in &nodes {
        let computed_size = node.size();
    }
}
```

After:
```rust
fn system(computed_nodes: Query<&ComputedNode>) {
    for computed_node in &computed_nodes {
        let computed_size = computed_node.size();
    }
}
```
2024-10-18 22:25:33 +00:00

339 lines
11 KiB
Rust

//! This example shows how to place reflection probes in the scene.
//!
//! Press Space to switch between no reflections, environment map reflections
//! (i.e. the skybox only, not the cubes), and a full reflection probe that
//! reflects the skybox and the cubes. Press Enter to pause rotation.
//!
//! Reflection probes don't work on WebGL 2 or WebGPU.
use bevy::{core_pipeline::Skybox, prelude::*};
use std::{
f32::consts::PI,
fmt::{Display, Formatter, Result as FmtResult},
};
static STOP_ROTATION_HELP_TEXT: &str = "Press Enter to stop rotation";
static START_ROTATION_HELP_TEXT: &str = "Press Enter to start rotation";
static REFLECTION_MODE_HELP_TEXT: &str = "Press Space to switch reflection mode";
// The mode the application is in.
#[derive(Resource)]
struct AppStatus {
// Which environment maps the user has requested to display.
reflection_mode: ReflectionMode,
// Whether the user has requested the scene to rotate.
rotating: bool,
}
// Which environment maps the user has requested to display.
#[derive(Clone, Copy)]
enum ReflectionMode {
// No environment maps are shown.
None = 0,
// Only a world environment map is shown.
EnvironmentMap = 1,
// Both a world environment map and a reflection probe are present. The
// reflection probe is shown in the sphere.
ReflectionProbe = 2,
}
// The various reflection maps.
#[derive(Resource)]
struct Cubemaps {
// The blurry diffuse cubemap. This is used for both the world environment
// map and the reflection probe. (In reality you wouldn't do this, but this
// reduces complexity of this example a bit.)
diffuse: Handle<Image>,
// The specular cubemap that reflects the world, but not the cubes.
specular_environment_map: Handle<Image>,
// The specular cubemap that reflects both the world and the cubes.
specular_reflection_probe: Handle<Image>,
// The skybox cubemap image. This is almost the same as
// `specular_environment_map`.
skybox: Handle<Image>,
}
fn main() {
// Create the app.
App::new()
.add_plugins(DefaultPlugins)
.init_resource::<AppStatus>()
.init_resource::<Cubemaps>()
.add_systems(Startup, setup)
.add_systems(PreUpdate, add_environment_map_to_camera)
.add_systems(Update, change_reflection_type)
.add_systems(Update, toggle_rotation)
.add_systems(
Update,
rotate_camera
.after(toggle_rotation)
.after(change_reflection_type),
)
.add_systems(Update, update_text.after(rotate_camera))
.run();
}
// Spawns all the scene objects.
fn setup(
mut commands: Commands,
mut meshes: ResMut<Assets<Mesh>>,
mut materials: ResMut<Assets<StandardMaterial>>,
asset_server: Res<AssetServer>,
app_status: Res<AppStatus>,
cubemaps: Res<Cubemaps>,
) {
spawn_scene(&mut commands, &asset_server);
spawn_camera(&mut commands);
spawn_sphere(&mut commands, &mut meshes, &mut materials);
spawn_reflection_probe(&mut commands, &cubemaps);
spawn_text(&mut commands, &app_status);
}
// Spawns the cubes, light, and camera.
fn spawn_scene(commands: &mut Commands, asset_server: &AssetServer) {
commands.spawn(SceneRoot(
asset_server.load(GltfAssetLabel::Scene(0).from_asset("models/cubes/Cubes.glb")),
));
}
// Spawns the camera.
fn spawn_camera(commands: &mut Commands) {
commands.spawn((
Camera3d::default(),
Camera {
hdr: true,
..default()
},
Transform::from_xyz(-6.483, 0.325, 4.381).looking_at(Vec3::ZERO, Vec3::Y),
));
}
// Creates the sphere mesh and spawns it.
fn spawn_sphere(
commands: &mut Commands,
meshes: &mut Assets<Mesh>,
materials: &mut Assets<StandardMaterial>,
) {
// Create a sphere mesh.
let sphere_mesh = meshes.add(Sphere::new(1.0).mesh().ico(7).unwrap());
// Create a sphere.
commands.spawn((
Mesh3d(sphere_mesh.clone()),
MeshMaterial3d(materials.add(StandardMaterial {
base_color: Srgba::hex("#ffd891").unwrap().into(),
metallic: 1.0,
perceptual_roughness: 0.0,
..StandardMaterial::default()
})),
));
}
// Spawns the reflection probe.
fn spawn_reflection_probe(commands: &mut Commands, cubemaps: &Cubemaps) {
commands.spawn((
LightProbe,
EnvironmentMapLight {
diffuse_map: cubemaps.diffuse.clone(),
specular_map: cubemaps.specular_reflection_probe.clone(),
intensity: 5000.0,
..default()
},
// 2.0 because the sphere's radius is 1.0 and we want to fully enclose it.
Transform::from_scale(Vec3::splat(2.0)),
));
}
// Spawns the help text.
fn spawn_text(commands: &mut Commands, app_status: &AppStatus) {
// Create the text.
commands.spawn((
app_status.create_text(),
Node {
position_type: PositionType::Absolute,
bottom: Val::Px(12.0),
left: Val::Px(12.0),
..default()
},
));
}
// Adds a world environment map to the camera. This separate system is needed because the camera is
// managed by the scene spawner, as it's part of the glTF file with the cubes, so we have to add
// the environment map after the fact.
fn add_environment_map_to_camera(
mut commands: Commands,
query: Query<Entity, Added<Camera3d>>,
cubemaps: Res<Cubemaps>,
) {
for camera_entity in query.iter() {
commands
.entity(camera_entity)
.insert(create_camera_environment_map_light(&cubemaps))
.insert(Skybox {
image: cubemaps.skybox.clone(),
brightness: 5000.0,
..default()
});
}
}
// A system that handles switching between different reflection modes.
fn change_reflection_type(
mut commands: Commands,
light_probe_query: Query<Entity, With<LightProbe>>,
camera_query: Query<Entity, With<Camera3d>>,
keyboard: Res<ButtonInput<KeyCode>>,
mut app_status: ResMut<AppStatus>,
cubemaps: Res<Cubemaps>,
) {
// Only do anything if space was pressed.
if !keyboard.just_pressed(KeyCode::Space) {
return;
}
// Switch reflection mode.
app_status.reflection_mode =
ReflectionMode::try_from((app_status.reflection_mode as u32 + 1) % 3).unwrap();
// Add or remove the light probe.
for light_probe in light_probe_query.iter() {
commands.entity(light_probe).despawn();
}
match app_status.reflection_mode {
ReflectionMode::None | ReflectionMode::EnvironmentMap => {}
ReflectionMode::ReflectionProbe => spawn_reflection_probe(&mut commands, &cubemaps),
}
// Add or remove the environment map from the camera.
for camera in camera_query.iter() {
match app_status.reflection_mode {
ReflectionMode::None => {
commands.entity(camera).remove::<EnvironmentMapLight>();
}
ReflectionMode::EnvironmentMap | ReflectionMode::ReflectionProbe => {
commands
.entity(camera)
.insert(create_camera_environment_map_light(&cubemaps));
}
}
}
}
// A system that handles enabling and disabling rotation.
fn toggle_rotation(keyboard: Res<ButtonInput<KeyCode>>, mut app_status: ResMut<AppStatus>) {
if keyboard.just_pressed(KeyCode::Enter) {
app_status.rotating = !app_status.rotating;
}
}
// A system that updates the help text.
fn update_text(mut text_query: Query<&mut Text>, app_status: Res<AppStatus>) {
for mut text in text_query.iter_mut() {
*text = app_status.create_text();
}
}
impl TryFrom<u32> for ReflectionMode {
type Error = ();
fn try_from(value: u32) -> Result<Self, Self::Error> {
match value {
0 => Ok(ReflectionMode::None),
1 => Ok(ReflectionMode::EnvironmentMap),
2 => Ok(ReflectionMode::ReflectionProbe),
_ => Err(()),
}
}
}
impl Display for ReflectionMode {
fn fmt(&self, formatter: &mut Formatter<'_>) -> FmtResult {
let text = match *self {
ReflectionMode::None => "No reflections",
ReflectionMode::EnvironmentMap => "Environment map",
ReflectionMode::ReflectionProbe => "Reflection probe",
};
formatter.write_str(text)
}
}
impl AppStatus {
// Constructs the help text at the bottom of the screen based on the
// application status.
fn create_text(&self) -> Text {
let rotation_help_text = if self.rotating {
STOP_ROTATION_HELP_TEXT
} else {
START_ROTATION_HELP_TEXT
};
format!(
"{}\n{}\n{}",
self.reflection_mode, rotation_help_text, REFLECTION_MODE_HELP_TEXT
)
.into()
}
}
// Creates the world environment map light, used as a fallback if no reflection
// probe is applicable to a mesh.
fn create_camera_environment_map_light(cubemaps: &Cubemaps) -> EnvironmentMapLight {
EnvironmentMapLight {
diffuse_map: cubemaps.diffuse.clone(),
specular_map: cubemaps.specular_environment_map.clone(),
intensity: 5000.0,
..default()
}
}
// Rotates the camera a bit every frame.
fn rotate_camera(
time: Res<Time>,
mut camera_query: Query<&mut Transform, With<Camera3d>>,
app_status: Res<AppStatus>,
) {
if !app_status.rotating {
return;
}
for mut transform in camera_query.iter_mut() {
transform.translation = Vec2::from_angle(time.delta_secs() * PI / 5.0)
.rotate(transform.translation.xz())
.extend(transform.translation.y)
.xzy();
transform.look_at(Vec3::ZERO, Vec3::Y);
}
}
// Loads the cubemaps from the assets directory.
impl FromWorld for Cubemaps {
fn from_world(world: &mut World) -> Self {
// Just use the specular map for the skybox since it's not too blurry.
// In reality you wouldn't do this--you'd use a real skybox texture--but
// reusing the textures like this saves space in the Bevy repository.
let specular_map = world.load_asset("environment_maps/pisa_specular_rgb9e5_zstd.ktx2");
Cubemaps {
diffuse: world.load_asset("environment_maps/pisa_diffuse_rgb9e5_zstd.ktx2"),
specular_reflection_probe: world
.load_asset("environment_maps/cubes_reflection_probe_specular_rgb9e5_zstd.ktx2"),
specular_environment_map: specular_map.clone(),
skybox: specular_map,
}
}
}
impl Default for AppStatus {
fn default() -> Self {
Self {
reflection_mode: ReflectionMode::ReflectionProbe,
rotating: true,
}
}
}