bevy/examples/3d/fog_volumes.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

88 lines
2.9 KiB
Rust

//! Demonstrates fog volumes with voxel density textures.
//!
//! We render the Stanford bunny as a fog volume. Parts of the bunny become
//! lighter and darker as the camera rotates. This is physically-accurate
//! behavior that results from the scattering and absorption of the directional
//! light.
use bevy::{
math::vec3,
pbr::{FogVolume, VolumetricFog, VolumetricLight},
prelude::*,
render::world_sync::SyncToRenderWorld,
};
/// Entry point.
fn main() {
App::new()
.add_plugins(DefaultPlugins.set(WindowPlugin {
primary_window: Some(Window {
title: "Bevy Fog Volumes Example".into(),
..default()
}),
..default()
}))
.insert_resource(AmbientLight::NONE)
.add_systems(Startup, setup)
.add_systems(Update, rotate_camera)
.run();
}
/// Spawns all the objects in the scene.
fn setup(mut commands: Commands, asset_server: Res<AssetServer>) {
// Spawn a fog volume with a voxelized version of the Stanford bunny.
commands
.spawn(SpatialBundle {
visibility: Visibility::Visible,
transform: Transform::from_xyz(0.0, 0.5, 0.0),
..default()
})
.insert(FogVolume {
density_texture: Some(asset_server.load("volumes/bunny.ktx2")),
density_factor: 1.0,
// Scatter as much of the light as possible, to brighten the bunny
// up.
scattering: 1.0,
..default()
})
// indicates that this fog volume needs to be Synchronized to the render world
.insert(SyncToRenderWorld);
// Spawn a bright directional light that illuminates the fog well.
commands.spawn((
Transform::from_xyz(1.0, 1.0, -0.3).looking_at(vec3(0.0, 0.5, 0.0), Vec3::Y),
DirectionalLight {
shadows_enabled: true,
illuminance: 32000.0,
..default()
},
// Make sure to add this for the light to interact with the fog.
VolumetricLight,
));
// Spawn a camera.
commands.spawn((
Camera3d::default(),
Transform::from_xyz(-0.75, 1.0, 2.0).looking_at(vec3(0.0, 0.0, 0.0), Vec3::Y),
Camera {
hdr: true,
..default()
},
VolumetricFog {
// Make this relatively high in order to increase the fog quality.
step_count: 64,
// Disable ambient light.
ambient_intensity: 0.0,
..default()
},
));
}
/// Rotates the camera a bit every frame.
fn rotate_camera(mut cameras: Query<&mut Transform, With<Camera3d>>) {
for mut camera_transform in cameras.iter_mut() {
*camera_transform =
Transform::from_translation(Quat::from_rotation_y(0.01) * camera_transform.translation)
.looking_at(vec3(0.0, 0.5, 0.0), Vec3::Y);
}
}