Unify picking backends (#17348)

# Objective

Currently, our picking backends are inconsistent:

- Mesh picking and sprite picking both have configurable opt in/out
behavior. UI picking does not.
- Sprite picking uses `SpritePickingCamera` and `Pickable` for control,
but mesh picking uses `RayCastPickable`.
- `MeshPickingPlugin` is not a part of `DefaultPlugins`.
`SpritePickingPlugin` and `UiPickingPlugin` are.

## Solution

- Add configurable opt in/out behavior to UI picking (defaults to opt
out).
- Replace `RayCastPickable` with `MeshPickingCamera` and `Pickable`.
- Remove `SpritePickingPlugin` and `UiPickingPlugin` from
`DefaultPlugins`.

## Testing

Ran some examples.

## Migration Guide

`UiPickingPlugin` and `SpritePickingPlugin` are no longer included in
`DefaultPlugins`. They must be explicitly added.

`RayCastPickable` has been replaced in favor of the `MeshPickingCamera`
and `Pickable` components. You should add them to cameras and entities,
respectively, if you have `MeshPickingSettings::require_markers` set to
`true`.

---------

Co-authored-by: Alice Cecile <alice.i.cecile@gmail.com>

Author: 2 people

crates/bevy_picking/src/lib.rs

@@ -179,7 +179,7 @@ pub mod prelude {
     #[doc(hidden)]
     pub use crate::mesh_picking::{
         ray_cast::{MeshRayCast, MeshRayCastSettings, RayCastBackfaces, RayCastVisibility},
-        MeshPickingPlugin, MeshPickingSettings, RayCastPickable,
+        MeshPickingCamera, MeshPickingPlugin, MeshPickingSettings,
     };
     #[doc(hidden)]
     pub use crate::{

crates/bevy_picking/src/mesh_picking/mod.rs

@@ -4,7 +4,8 @@
 //! by adding [`Pickable::IGNORE`].
 //!
 //! To make mesh picking entirely opt-in, set [`MeshPickingSettings::require_markers`]
-//! to `true` and add a [`RayCastPickable`] component to the desired camera and target entities.
+//! to `true` and add [`MeshPickingCamera`] and [`Pickable`] components to the desired camera and
+//! target entities.
 //!
 //! To manually perform mesh ray casts independent of picking, use the [`MeshRayCast`] system parameter.
 //!
@@ -26,12 +27,19 @@ use bevy_reflect::prelude::*;
 use bevy_render::{prelude::*, view::RenderLayers};
 use ray_cast::{MeshRayCast, MeshRayCastSettings, RayCastVisibility, SimplifiedMesh};
 
+/// An optional component that marks cameras that should be used in the [`MeshPickingPlugin`].
+///
+/// Only needed if [`MeshPickingSettings::require_markers`] is set to `true`, and ignored otherwise.
+#[derive(Debug, Clone, Default, Component, Reflect)]
+#[reflect(Debug, Default, Component)]
+pub struct MeshPickingCamera;
+
 /// Runtime settings for the [`MeshPickingPlugin`].
 #[derive(Resource, Reflect)]
 #[reflect(Resource, Default)]
 pub struct MeshPickingSettings {
-    /// When set to `true` ray casting will only happen between cameras and entities marked with
-    /// [`RayCastPickable`]. `false` by default.
+    /// When set to `true` ray casting will only consider cameras marked with
+    /// [`MeshPickingCamera`] and entities marked with [`Pickable`]. `false` by default.
     ///
     /// This setting is provided to give you fine-grained control over which cameras and entities
     /// should be used by the mesh picking backend at runtime.
@@ -54,20 +62,13 @@ impl Default for MeshPickingSettings {
     }
 }
 
-/// An optional component that marks cameras and target entities that should be used in the [`MeshPickingPlugin`].
-/// Only needed if [`MeshPickingSettings::require_markers`] is set to `true`, and ignored otherwise.
-#[derive(Debug, Clone, Default, Component, Reflect)]
-#[reflect(Component, Default, Clone)]
-pub struct RayCastPickable;
-
 /// Adds the mesh picking backend to your app.
 #[derive(Clone, Default)]
 pub struct MeshPickingPlugin;
 
 impl Plugin for MeshPickingPlugin {
     fn build(&self, app: &mut App) {
         app.init_resource::<MeshPickingSettings>()
-            .register_type::<RayCastPickable>()
             .register_type::<MeshPickingSettings>()
             .register_type::<SimplifiedMesh>()
             .add_systems(PreUpdate, update_hits.in_set(PickSet::Backend));
@@ -78,18 +79,18 @@ impl Plugin for MeshPickingPlugin {
 pub fn update_hits(
     backend_settings: Res<MeshPickingSettings>,
     ray_map: Res<RayMap>,
-    picking_cameras: Query<(&Camera, Option<&RayCastPickable>, Option<&RenderLayers>)>,
+    picking_cameras: Query<(&Camera, Has<MeshPickingCamera>, Option<&RenderLayers>)>,
     pickables: Query<&Pickable>,
-    marked_targets: Query<&RayCastPickable>,
+    marked_targets: Query<&Pickable>,
     layers: Query<&RenderLayers>,
     mut ray_cast: MeshRayCast,
     mut output: EventWriter<PointerHits>,
 ) {
     for (&ray_id, &ray) in ray_map.map().iter() {
-        let Ok((camera, cam_pickable, cam_layers)) = picking_cameras.get(ray_id.camera) else {
+        let Ok((camera, cam_can_pick, cam_layers)) = picking_cameras.get(ray_id.camera) else {
             continue;
         };
-        if backend_settings.require_markers && cam_pickable.is_none() {
+        if backend_settings.require_markers && !cam_can_pick {
             continue;
         }
 

crates/bevy_sprite/src/lib.rs

@@ -21,6 +21,11 @@ mod texture_slice;
 ///
 /// This includes the most common types in this crate, re-exported for your convenience.
 pub mod prelude {
+    #[cfg(feature = "bevy_sprite_picking_backend")]
+    #[doc(hidden)]
+    pub use crate::picking_backend::{
+        SpritePickingCamera, SpritePickingMode, SpritePickingPlugin, SpritePickingSettings,
+    };
     #[doc(hidden)]
     pub use crate::{
         sprite::{Sprite, SpriteImageMode},
@@ -52,28 +57,8 @@ use bevy_render::{
 };
 
 /// Adds support for 2D sprite rendering.
-pub struct SpritePlugin {
-    /// Whether to add the sprite picking backend to the app.
-    #[cfg(feature = "bevy_sprite_picking_backend")]
-    pub add_picking: bool,
-}
-
-#[expect(
-    clippy::allow_attributes,
-    reason = "clippy::derivable_impls is not always linted"
-)]
-#[allow(
-    clippy::derivable_impls,
-    reason = "Known false positive with clippy: <https://github.com/rust-lang/rust-clippy/issues/13160>"
-)]
-impl Default for SpritePlugin {
-    fn default() -> Self {
-        Self {
-            #[cfg(feature = "bevy_sprite_picking_backend")]
-            add_picking: true,
-        }
-    }
-}
+#[derive(Default)]
+pub struct SpritePlugin;
 
 pub const SPRITE_SHADER_HANDLE: Handle<Shader> =
     weak_handle!("ed996613-54c0-49bd-81be-1c2d1a0d03c2");
@@ -125,9 +110,7 @@ impl Plugin for SpritePlugin {
             );
 
         #[cfg(feature = "bevy_sprite_picking_backend")]
-        if self.add_picking {
-            app.add_plugins(SpritePickingPlugin);
-        }
+        app.add_plugins(SpritePickingPlugin);
 
         if let Some(render_app) = app.get_sub_app_mut(RenderApp) {
             render_app

crates/bevy_sprite/src/picking_backend.rs

@@ -20,7 +20,10 @@ use bevy_render::prelude::*;
 use bevy_transform::prelude::*;
 use bevy_window::PrimaryWindow;
 
-/// A component that marks cameras that should be used in the [`SpritePickingPlugin`].
+/// An optional component that marks cameras that should be used in the [`SpritePickingPlugin`].
+///
+/// Only needed if [`SpritePickingSettings::require_markers`] is set to `true`, and ignored
+/// otherwise.
 #[derive(Debug, Clone, Default, Component, Reflect)]
 #[reflect(Debug, Default, Component, Clone)]
 pub struct SpritePickingCamera;
@@ -62,6 +65,7 @@ impl Default for SpritePickingSettings {
     }
 }
 
+/// Enables the sprite picking backend, allowing you to click on, hover over and drag sprites.
 #[derive(Clone)]
 pub struct SpritePickingPlugin;
 

crates/bevy_ui/src/lib.rs

@@ -35,6 +35,7 @@ pub use focus::*;
 pub use geometry::*;
 pub use layout::*;
 pub use measurement::*;
+use prelude::UiPickingPlugin;
 pub use render::*;
 pub use ui_material::*;
 pub use ui_node::*;
@@ -45,6 +46,9 @@ use widget::{ImageNode, ImageNodeSize};
 ///
 /// This includes the most common types in this crate, re-exported for your convenience.
 pub mod prelude {
+    #[cfg(feature = "bevy_ui_picking_backend")]
+    #[doc(hidden)]
+    pub use crate::picking_backend::{UiPickingCamera, UiPickingPlugin, UiPickingSettings};
     #[doc(hidden)]
     #[cfg(feature = "bevy_ui_debug")]
     pub use crate::render::UiDebugOptions;
@@ -79,17 +83,12 @@ pub struct UiPlugin {
     /// If set to false, the UI's rendering systems won't be added to the `RenderApp` and no UI elements will be drawn.
     /// The layout and interaction components will still be updated as normal.
     pub enable_rendering: bool,
-    /// Whether to add the UI picking backend to the app.
-    #[cfg(feature = "bevy_ui_picking_backend")]
-    pub add_picking: bool,
 }
 
 impl Default for UiPlugin {
     fn default() -> Self {
         Self {
             enable_rendering: true,
-            #[cfg(feature = "bevy_ui_picking_backend")]
-            add_picking: true,
         }
     }
 }
@@ -181,6 +180,7 @@ impl Plugin for UiPlugin {
                 )
                     .chain(),
             )
+            .add_plugins(UiPickingPlugin)
             .add_systems(
                 PreUpdate,
                 ui_focus_system.in_set(UiSystem::Focus).after(InputSystem),
@@ -219,11 +219,6 @@ impl Plugin for UiPlugin {
         );
         build_text_interop(app);
 
-        #[cfg(feature = "bevy_ui_picking_backend")]
-        if self.add_picking {
-            app.add_plugins(picking_backend::UiPickingPlugin);
-        }
-
         if !self.enable_rendering {
             return;
         }

crates/bevy_ui/src/picking_backend.rs

@@ -29,18 +29,59 @@ use bevy_app::prelude::*;
 use bevy_ecs::{prelude::*, query::QueryData};
 use bevy_math::{Rect, Vec2};
 use bevy_platform_support::collections::HashMap;
+use bevy_reflect::{std_traits::ReflectDefault, Reflect};
 use bevy_render::prelude::*;
 use bevy_transform::prelude::*;
 use bevy_window::PrimaryWindow;
 
 use bevy_picking::backend::prelude::*;
 
+/// An optional component that marks cameras that should be used in the [`UiPickingPlugin`].
+///
+/// Only needed if [`UiPickingSettings::require_markers`] is set to `true`, and ignored
+/// otherwise.
+#[derive(Debug, Clone, Default, Component, Reflect)]
+#[reflect(Debug, Default, Component)]
+pub struct UiPickingCamera;
+
+/// Runtime settings for the [`UiPickingPlugin`].
+#[derive(Resource, Reflect)]
+#[reflect(Resource, Default)]
+pub struct UiPickingSettings {
+    /// When set to `true` UI picking will only consider cameras marked with
+    /// [`UiPickingCamera`] and entities marked with [`Pickable`]. `false` by default.
+    ///
+    /// This setting is provided to give you fine-grained control over which cameras and entities
+    /// should be used by the UI picking backend at runtime.
+    pub require_markers: bool,
+}
+
+#[expect(
+    clippy::allow_attributes,
+    reason = "clippy::derivable_impls is not always linted"
+)]
+#[allow(
+    clippy::derivable_impls,
+    reason = "Known false positive with clippy: <https://github.com/rust-lang/rust-clippy/issues/13160>"
+)]
+impl Default for UiPickingSettings {
+    fn default() -> Self {
+        Self {
+            require_markers: false,
+        }
+    }
+}
+
 /// A plugin that adds picking support for UI nodes.
+///
+/// This is included by default in [`UiPlugin`](crate::UiPlugin).
 #[derive(Clone)]
 pub struct UiPickingPlugin;
 impl Plugin for UiPickingPlugin {
     fn build(&self, app: &mut App) {
-        app.add_systems(PreUpdate, ui_picking.in_set(PickSet::Backend));
+        app.init_resource::<UiPickingSettings>()
+            .register_type::<(UiPickingCamera, UiPickingSettings)>()
+            .add_systems(PreUpdate, ui_picking.in_set(PickSet::Backend));
     }
 }
 
@@ -63,8 +104,14 @@ pub struct NodeQuery {
 /// we need for determining picking.
 pub fn ui_picking(
     pointers: Query<(&PointerId, &PointerLocation)>,
-    camera_query: Query<(Entity, &Camera, Has<IsDefaultUiCamera>)>,
+    camera_query: Query<(
+        Entity,
+        &Camera,
+        Has<IsDefaultUiCamera>,
+        Has<UiPickingCamera>,
+    )>,
     primary_window: Query<Entity, With<PrimaryWindow>>,
+    settings: Res<UiPickingSettings>,
     ui_stack: Res<UiStack>,
     node_query: Query<NodeQuery>,
     mut output: EventWriter<PointerHits>,
@@ -81,7 +128,8 @@ pub fn ui_picking(
         // cameras. We want to ensure we return all cameras with a matching target.
         for camera in camera_query
             .iter()
-            .map(|(entity, camera, _)| {
+            .filter(|(_, _, _, cam_can_pick)| !settings.require_markers || *cam_can_pick)
+            .map(|(entity, camera, _, _)| {
                 (
                     entity,
                     camera.target.normalize(primary_window.single().ok()),
@@ -91,7 +139,7 @@ pub fn ui_picking(
             .filter(|(_entity, target)| target == &pointer_location.target)
             .map(|(cam_entity, _target)| cam_entity)
         {
-            let Ok((_, camera_data, _)) = camera_query.get(camera) else {
+            let Ok((_, camera_data, _, _)) = camera_query.get(camera) else {
                 continue;
             };
             let mut pointer_pos =
@@ -122,6 +170,10 @@ pub fn ui_picking(
             continue;
         };
 
+        if settings.require_markers && node.pickable.is_none() {
+            continue;
+        }
+
         // Nodes that are not rendered should not be interactable
         if node
             .inherited_visibility
@@ -208,7 +260,7 @@ pub fn ui_picking(
 
         let order = camera_query
             .get(*camera)
-            .map(|(_, cam, _)| cam.order)
+            .map(|(_, cam, _, _)| cam.order)
             .unwrap_or_default() as f32
             + 0.5; // bevy ui can run on any camera, it's a special case
 

examples/picking/debug_picking.rs

@@ -10,8 +10,7 @@ fn main() {
             filter: "bevy_dev_tools=trace".into(), // Show picking logs trace level and up
             ..default()
         }))
-        // Unlike UiPickingPlugin, MeshPickingPlugin is not a default plugin
-        .add_plugins((MeshPickingPlugin, DebugPickingPlugin))
+        .add_plugins((MeshPickingPlugin, DebugPickingPlugin, UiPickingPlugin))
         .add_systems(Startup, setup_scene)
         .insert_resource(DebugPickingMode::Normal)
         // A system that cycles the debugging state when you press F3:

examples/picking/mesh_picking.rs

@@ -16,8 +16,8 @@
 //!
 //! By default, the mesh picking plugin will raycast against all entities, which is especially
 //! useful for debugging. If you want mesh picking to be opt-in, you can set
-//! [`MeshPickingSettings::require_markers`] to `true` and add a [`RayCastPickable`] component to
-//! the desired camera and target entities.
+//! [`MeshPickingSettings::require_markers`] to `true` and add a [`Pickable`] component to the
+//! desired camera and target entities.
 
 use std::f32::consts::PI;
 

examples/picking/simple_picking.rs

@@ -4,8 +4,7 @@ use bevy::prelude::*;
 
 fn main() {
     App::new()
-        // Unlike UiPickingPlugin, MeshPickingPlugin is not a default plugin
-        .add_plugins((DefaultPlugins, MeshPickingPlugin))
+        .add_plugins((DefaultPlugins, MeshPickingPlugin, UiPickingPlugin))
         .add_systems(Startup, setup_scene)
         .run();
 }

examples/picking/sprite_picking.rs

@@ -6,7 +6,10 @@ use std::fmt::Debug;
 
 fn main() {
     App::new()
-        .add_plugins(DefaultPlugins.set(ImagePlugin::default_nearest()))
+        .add_plugins((
+            DefaultPlugins.set(ImagePlugin::default_nearest()),
+            SpritePickingPlugin,
+        ))
         .add_systems(Startup, (setup, setup_atlas))
         .add_systems(Update, (move_sprite, animate_sprite))
         .run();