bevy/examples/3d/3d_viewport_to_world.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

76 lines
2 KiB
Rust

//! This example demonstrates how to use the `Camera::viewport_to_world` method.
use bevy::prelude::*;
fn main() {
App::new()
.add_plugins(DefaultPlugins)
.add_systems(Startup, setup)
.add_systems(Update, draw_cursor)
.run();
}
fn draw_cursor(
camera_query: Query<(&Camera, &GlobalTransform)>,
ground_query: Query<&GlobalTransform, With<Ground>>,
windows: Query<&Window>,
mut gizmos: Gizmos,
) {
let (camera, camera_transform) = camera_query.single();
let ground = ground_query.single();
let Some(cursor_position) = windows.single().cursor_position() else {
return;
};
// Calculate a ray pointing from the camera into the world based on the cursor's position.
let Ok(ray) = camera.viewport_to_world(camera_transform, cursor_position) else {
return;
};
// Calculate if and where the ray is hitting the ground plane.
let Some(distance) =
ray.intersect_plane(ground.translation(), InfinitePlane3d::new(ground.up()))
else {
return;
};
let point = ray.get_point(distance);
// Draw a circle just above the ground plane at that position.
gizmos.circle(
Isometry3d::new(
point + ground.up() * 0.01,
Quat::from_rotation_arc(Vec3::Z, ground.up().as_vec3()),
),
0.2,
Color::WHITE,
);
}
#[derive(Component)]
struct Ground;
fn setup(
mut commands: Commands,
mut meshes: ResMut<Assets<Mesh>>,
mut materials: ResMut<Assets<StandardMaterial>>,
) {
// plane
commands.spawn((
Mesh3d(meshes.add(Plane3d::default().mesh().size(20., 20.))),
MeshMaterial3d(materials.add(Color::srgb(0.3, 0.5, 0.3))),
Ground,
));
// light
commands.spawn((
DirectionalLight::default(),
Transform::from_translation(Vec3::ONE).looking_at(Vec3::ZERO, Vec3::Y),
));
// camera
commands.spawn((
Camera3d::default(),
Transform::from_xyz(15.0, 5.0, 15.0).looking_at(Vec3::ZERO, Vec3::Y),
));
}