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.

Cargo.toml

@@ -346,7 +346,7 @@ android_shared_stdcxx = ["bevy_internal/android_shared_stdcxx"]
 # Enable detailed trace event logging. These trace events are expensive even when off, thus they require compile time opt-in
 detailed_trace = ["bevy_internal/detailed_trace"]
 
-# Include tonemapping Look Up Tables KTX2 files. If everything is pink, you need to enable this feature or change the `Tonemapping` method on your `Camera2dBundle` or `Camera3dBundle`.
+# Include tonemapping Look Up Tables KTX2 files. If everything is pink, you need to enable this feature or change the `Tonemapping` method for your `Camera2d` or `Camera3d`.
 tonemapping_luts = ["bevy_internal/tonemapping_luts", "ktx2", "zstd"]
 
 # Include SMAA Look Up Tables KTX2 Files

crates/bevy_core_pipeline/src/core_2d/camera_2d.rs

@@ -1,3 +1,5 @@
+#![expect(deprecated)]
+
 use crate::{
     core_2d::graph::Core2d,
     tonemapping::{DebandDither, Tonemapping},
@@ -17,12 +19,25 @@ use bevy_render::{
 };
 use bevy_transform::prelude::{GlobalTransform, Transform};
 
+/// A 2D camera component. Enables the 2D render graph for a [`Camera`].
 #[derive(Component, Default, Reflect, Clone, ExtractComponent)]
 #[extract_component_filter(With<Camera>)]
 #[reflect(Component, Default)]
+#[require(
+    Camera,
+    DebandDither,
+    CameraRenderGraph(|| CameraRenderGraph::new(Core2d)),
+    OrthographicProjection(OrthographicProjection::default_2d),
+    Frustum(|| OrthographicProjection::default_2d().compute_frustum(&GlobalTransform::from(Transform::default()))),
+    Tonemapping(|| Tonemapping::None),
+)]
 pub struct Camera2d;
 
 #[derive(Bundle, Clone)]
+#[deprecated(
+    since = "0.15.0",
+    note = "Use the `Camera2d` component instead. Inserting it will now also insert the other components required by it automatically."
+)]
 pub struct Camera2dBundle {
     pub camera: Camera,
     pub camera_render_graph: CameraRenderGraph,

crates/bevy_core_pipeline/src/core_3d/camera_3d.rs

@@ -1,3 +1,5 @@
+#![expect(deprecated)]
+
 use crate::{
     core_3d::graph::Core3d,
     tonemapping::{DebandDither, Tonemapping},
@@ -15,12 +17,22 @@ use bevy_render::{
 use bevy_transform::prelude::{GlobalTransform, Transform};
 use serde::{Deserialize, Serialize};
 
-/// Configuration for the "main 3d render graph".
-/// The camera coordinate space is right-handed x-right, y-up, z-back.
+/// A 3D camera component. Enables the main 3D render graph for a [`Camera`].
+///
+/// The camera coordinate space is right-handed X-right, Y-up, Z-back.
 /// This means "forward" is -Z.
 #[derive(Component, Reflect, Clone, ExtractComponent)]
 #[extract_component_filter(With<Camera>)]
 #[reflect(Component, Default)]
+#[require(
+    Camera,
+    DebandDither(|| DebandDither::Enabled),
+    CameraRenderGraph(|| CameraRenderGraph::new(Core3d)),
+    Projection,
+    Tonemapping,
+    ColorGrading,
+    Exposure
+)]
 pub struct Camera3d {
     /// The depth clear operation to perform for the main 3d pass.
     pub depth_load_op: Camera3dDepthLoadOp,
@@ -139,6 +151,10 @@ pub enum ScreenSpaceTransmissionQuality {
 /// The camera coordinate space is right-handed x-right, y-up, z-back.
 /// This means "forward" is -Z.
 #[derive(Bundle, Clone)]
+#[deprecated(
+    since = "0.15.0",
+    note = "Use the `Camera3d` component instead. Inserting it will now also insert the other components required by it automatically."
+)]
 pub struct Camera3dBundle {
     pub camera: Camera,
     pub camera_render_graph: CameraRenderGraph,

crates/bevy_core_pipeline/src/lib.rs

@@ -45,6 +45,7 @@ pub mod experimental {
 /// The core pipeline prelude.
 ///
 /// This includes the most common types in this crate, re-exported for your convenience.
+#[expect(deprecated)]
 pub mod prelude {
     #[doc(hidden)]
     pub use crate::{

crates/bevy_core_pipeline/src/motion_blur/mod.rs

@@ -59,11 +59,11 @@ pub struct MotionBlurBundle {
 /// camera.
 ///
 /// ```
-/// # use bevy_core_pipeline::{core_3d::Camera3dBundle, motion_blur::MotionBlur};
+/// # use bevy_core_pipeline::{core_3d::Camera3d, motion_blur::MotionBlur};
 /// # use bevy_ecs::prelude::*;
 /// # fn test(mut commands: Commands) {
 /// commands.spawn((
-///     Camera3dBundle::default(),
+///     Camera3d::default(),
 ///     MotionBlur::default(),
 /// ));
 /// # }

crates/bevy_core_pipeline/src/tonemapping/mod.rs

@@ -263,7 +263,7 @@ impl SpecializedRenderPipeline for TonemappingPipeline {
                 error!(
                     "AgX tonemapping requires the `tonemapping_luts` feature.
                     Either enable the `tonemapping_luts` feature for bevy in `Cargo.toml` (recommended),
-                    or use a different `Tonemapping` method in your `Camera2dBundle`/`Camera3dBundle`."
+                    or use a different `Tonemapping` method for your `Camera2d`/`Camera3d`."
                 );
                 shader_defs.push("TONEMAP_METHOD_AGX".into());
             }
@@ -275,7 +275,7 @@ impl SpecializedRenderPipeline for TonemappingPipeline {
                 error!(
                     "TonyMcMapFace tonemapping requires the `tonemapping_luts` feature.
                     Either enable the `tonemapping_luts` feature for bevy in `Cargo.toml` (recommended),
-                    or use a different `Tonemapping` method in your `Camera2dBundle`/`Camera3dBundle`."
+                    or use a different `Tonemapping` method for your `Camera2d`/`Camera3d`."
                 );
                 shader_defs.push("TONEMAP_METHOD_TONY_MC_MAPFACE".into());
             }
@@ -284,7 +284,7 @@ impl SpecializedRenderPipeline for TonemappingPipeline {
                 error!(
                     "BlenderFilmic tonemapping requires the `tonemapping_luts` feature.
                     Either enable the `tonemapping_luts` feature for bevy in `Cargo.toml` (recommended),
-                    or use a different `Tonemapping` method in your `Camera2dBundle`/`Camera3dBundle`."
+                    or use a different `Tonemapping` method for your `Camera2d`/`Camera3d`."
                 );
                 shader_defs.push("TONEMAP_METHOD_BLENDER_FILMIC".into());
             }

crates/bevy_dev_tools/src/ui_debug_overlay/mod.rs

@@ -4,7 +4,7 @@ use core::any::{Any, TypeId};
 use bevy_app::{App, Plugin, PostUpdate};
 use bevy_color::Hsla;
 use bevy_core::Name;
-use bevy_core_pipeline::core_2d::Camera2dBundle;
+use bevy_core_pipeline::core_2d::Camera2d;
 use bevy_ecs::{prelude::*, system::SystemParam};
 use bevy_gizmos::{config::GizmoConfigStore, prelude::Gizmos, AppGizmoBuilder};
 use bevy_hierarchy::{Children, Parent};
@@ -88,17 +88,15 @@ fn update_debug_camera(
     } else {
         let spawn_cam = || {
             cmds.spawn((
-                Camera2dBundle {
-                    projection: OrthographicProjection {
-                        far: 1000.0,
-                        viewport_origin: Vec2::new(0.0, 0.0),
-                        ..OrthographicProjection::default_3d()
-                    },
-                    camera: Camera {
-                        order: LAYOUT_DEBUG_CAMERA_ORDER,
-                        clear_color: ClearColorConfig::None,
-                        ..default()
-                    },
+                Camera2d,
+                OrthographicProjection {
+                    far: 1000.0,
+                    viewport_origin: Vec2::new(0.0, 0.0),
+                    ..OrthographicProjection::default_3d()
+                },
+                Camera {
+                    order: LAYOUT_DEBUG_CAMERA_ORDER,
+                    clear_color: ClearColorConfig::None,
                     ..default()
                 },
                 LAYOUT_DEBUG_LAYERS.clone(),

crates/bevy_ecs/src/bundle.rs

@@ -55,9 +55,6 @@ use core::{any::TypeId, ptr::NonNull};
 /// would create incoherent behavior.
 /// This would be unexpected if bundles were treated as an abstraction boundary, as
 /// the abstraction would be unmaintainable for these cases.
-/// For example, both `Camera3dBundle` and `Camera2dBundle` contain the `CameraRenderGraph`
-/// component, but specifying different render graphs to use.
-/// If the bundles were both added to the same entity, only one of these two bundles would work.
 ///
 /// For this reason, there is intentionally no [`Query`] to match whether an entity
 /// contains the components of a bundle.

crates/bevy_gltf/src/loader.rs

@@ -9,7 +9,7 @@ use bevy_asset::{
 };
 use bevy_color::{Color, LinearRgba};
 use bevy_core::Name;
-use bevy_core_pipeline::prelude::Camera3dBundle;
+use bevy_core_pipeline::prelude::Camera3d;
 use bevy_ecs::{
     entity::{Entity, EntityHashMap},
     world::World,
@@ -1413,15 +1413,15 @@ fn load_node(
                     Projection::Perspective(perspective_projection)
                 }
             };
-            node.insert(Camera3dBundle {
+            node.insert((
+                Camera3d::default(),
                 projection,
                 transform,
-                camera: Camera {
+                Camera {
                     is_active: !*active_camera_found,
                     ..Default::default()
                 },
-                ..Default::default()
-            });
+            ));
 
             *active_camera_found = true;
         }

crates/bevy_pbr/src/fog.rs

@@ -29,10 +29,7 @@ use bevy_render::{extract_component::ExtractComponent, prelude::Camera};
 /// # fn system(mut commands: Commands) {
 /// commands.spawn((
 ///     // Setup your camera as usual
-///     Camera3dBundle {
-///         // ... camera options
-/// #       ..Default::default()
-///     },
+///     Camera3d::default(),
 ///     // Add fog to the same entity
 ///     DistanceFog {
 ///         color: Color::WHITE,

crates/bevy_render/src/camera/camera.rs

@@ -8,27 +8,29 @@ use crate::{
     render_resource::TextureView,
     texture::GpuImage,
     view::{
-        ColorGrading, ExtractedView, ExtractedWindows, GpuCulling, RenderLayers, VisibleEntities,
+        ColorGrading, ExtractedView, ExtractedWindows, GpuCulling, Msaa, RenderLayers, Visibility,
+        VisibleEntities,
     },
-    world_sync::RenderEntity,
+    world_sync::{RenderEntity, SyncToRenderWorld},
     Extract,
 };
 use bevy_asset::{AssetEvent, AssetId, Assets, Handle};
 use bevy_derive::{Deref, DerefMut};
 use bevy_ecs::{
     change_detection::DetectChanges,
-    component::Component,
+    component::{Component, ComponentId},
     entity::Entity,
     event::EventReader,
     prelude::With,
     query::Has,
     reflect::ReflectComponent,
     system::{Commands, Query, Res, ResMut, Resource},
+    world::DeferredWorld,
 };
 use bevy_math::{ops, vec2, Dir3, Mat4, Ray3d, Rect, URect, UVec2, UVec4, Vec2, Vec3};
 use bevy_reflect::prelude::*;
 use bevy_render_macros::ExtractComponent;
-use bevy_transform::components::GlobalTransform;
+use bevy_transform::components::{GlobalTransform, Transform};
 use bevy_utils::{tracing::warn, warn_once, HashMap, HashSet};
 use bevy_window::{
     NormalizedWindowRef, PrimaryWindow, Window, WindowCreated, WindowRef, WindowResized,
@@ -274,10 +276,25 @@ pub enum ViewportConversionError {
 /// to transform the 3D objects into a 2D image, as well as the render target into which that image
 /// is produced.
 ///
-/// Adding a camera is typically done by adding a bundle, either the `Camera2dBundle` or the
-/// `Camera3dBundle`.
+/// Note that a [`Camera`] needs a [`CameraRenderGraph`] to render anything.
+/// This is typically provided by adding a [`Camera2d`] or [`Camera3d`] component,
+/// but custom render graphs can also be defined. Inserting a [`Camera`] with no render
+/// graph will emit an error at runtime.
+///
+/// [`Camera2d`]: https://docs.rs/crate/bevy_core_pipeline/latest/core_2d/struct.Camera2d.html
+/// [`Camera3d`]: https://docs.rs/crate/bevy_core_pipeline/latest/core_3d/struct.Camera3d.html
 #[derive(Component, Debug, Reflect, Clone)]
 #[reflect(Component, Default, Debug)]
+#[component(on_add = warn_on_no_render_graph)]
+#[require(
+    Frustum,
+    CameraMainTextureUsages,
+    VisibleEntities,
+    Transform,
+    Visibility,
+    Msaa,
+    SyncToRenderWorld
+)]
 pub struct Camera {
     /// If set, this camera will render to the given [`Viewport`] rectangle within the configured [`RenderTarget`].
     pub viewport: Option<Viewport>,
@@ -309,6 +326,12 @@ pub struct Camera {
     pub sub_camera_view: Option<SubCameraView>,
 }
 
+fn warn_on_no_render_graph(world: DeferredWorld, entity: Entity, _: ComponentId) {
+    if !world.entity(entity).contains::<CameraRenderGraph>() {
+        warn!("Entity {entity} has a `Camera` component, but it doesn't have a render graph configured. Consider adding a `Camera2d` or `Camera3d` component, or manually adding a `CameraRenderGraph` component if you need a custom render graph.");
+    }
+}
+
 impl Default for Camera {
     fn default() -> Self {
         Self {

crates/bevy_render/src/primitives/mod.rs

@@ -200,8 +200,7 @@ impl HalfSpace {
 /// This process is called frustum culling, and entities can opt out of it using
 /// the [`NoFrustumCulling`] component.
 ///
-/// The frustum component is typically added from a bundle, either the `Camera2dBundle`
-/// or the `Camera3dBundle`.
+/// The frustum component is typically added automatically for cameras, either `Camera2d` or `Camera3d`.
 /// It is usually updated automatically by [`update_frusta`] from the
 /// [`CameraProjection`] component and [`GlobalTransform`] of the camera entity.
 ///

crates/bevy_text/src/text2d.rs

@@ -27,7 +27,7 @@ use bevy_transform::prelude::{GlobalTransform, Transform};
 use bevy_utils::HashSet;
 use bevy_window::{PrimaryWindow, Window, WindowScaleFactorChanged};
 
-/// The bundle of components needed to draw text in a 2D scene via a 2D `Camera2dBundle`.
+/// The bundle of components needed to draw text in a 2D scene via a `Camera2d`.
 /// [Example usage.](https://github.com/bevyengine/bevy/blob/latest/examples/2d/text2d.rs)
 #[derive(Bundle, Clone, Debug, Default)]
 pub struct Text2dBundle {

crates/bevy_ui/src/layout/mod.rs

@@ -464,7 +464,7 @@ mod tests {
     use taffy::TraversePartialTree;
 
     use bevy_asset::{AssetEvent, Assets};
-    use bevy_core_pipeline::core_2d::Camera2dBundle;
+    use bevy_core_pipeline::core_2d::Camera2d;
     use bevy_ecs::{
         entity::Entity,
         event::Events,
@@ -539,7 +539,7 @@ mod tests {
             },
             PrimaryWindow,
         ));
-        world.spawn(Camera2dBundle::default());
+        world.spawn(Camera2d);
 
         let mut ui_schedule = Schedule::default();
         ui_schedule.add_systems(
@@ -646,7 +646,7 @@ mod tests {
         assert!(ui_surface.camera_entity_to_taffy.is_empty());
 
         // respawn camera
-        let camera_entity = world.spawn(Camera2dBundle::default()).id();
+        let camera_entity = world.spawn(Camera2d).id();
 
         let ui_entity = world
             .spawn((NodeBundle::default(), TargetCamera(camera_entity)))
@@ -970,13 +970,13 @@ mod tests {
 
         let (mut world, mut ui_schedule) = setup_ui_test_world();
 
-        world.spawn(Camera2dBundle {
-            camera: Camera {
+        world.spawn((
+            Camera2d,
+            Camera {
                 order: 1,
                 ..default()
             },
-            ..default()
-        });
+        ));
 
         world.spawn((
             NodeBundle {

crates/bevy_ui/src/ui_node.rs

@@ -2437,7 +2437,7 @@ impl TargetCamera {
 /// # use bevy_ui::prelude::*;
 /// # use bevy_ecs::prelude::Commands;
 /// # use bevy_render::camera::{Camera, RenderTarget};
-/// # use bevy_core_pipeline::prelude::Camera2dBundle;
+/// # use bevy_core_pipeline::prelude::Camera2d;
 /// # use bevy_window::{Window, WindowRef};
 ///
 /// fn spawn_camera(mut commands: Commands) {
@@ -2446,11 +2446,9 @@ impl TargetCamera {
 ///         ..Default::default()
 ///     }).id();
 ///     commands.spawn((
-///         Camera2dBundle {
-///             camera: Camera {
-///                 target: RenderTarget::Window(WindowRef::Entity(another_window)),
-///                 ..Default::default()
-///             },
+///         Camera2d,
+///         Camera {
+///             target: RenderTarget::Window(WindowRef::Entity(another_window)),
 ///             ..Default::default()
 ///         },
 ///         // We add the Marker here so all Ui will spawn in
@@ -2502,7 +2500,7 @@ impl<'w, 's> DefaultUiCamera<'w, 's> {
 ///
 /// fn spawn_camera(mut commands: Commands) {
 ///     commands.spawn((
-///         Camera2dBundle::default(),
+///         Camera2d,
 ///         // This will cause all Ui in this camera to be rendered without
 ///         // anti-aliasing
 ///         UiAntiAlias::Off,

docs/cargo_features.md

@@ -41,7 +41,7 @@ The default feature set enables most of the expected features of a game engine,
 |png|PNG image format support|
 |smaa_luts|Include SMAA Look Up Tables KTX2 Files|
 |sysinfo_plugin|Enables system information diagnostic plugin|
-|tonemapping_luts|Include tonemapping Look Up Tables KTX2 files. If everything is pink, you need to enable this feature or change the `Tonemapping` method on your `Camera2dBundle` or `Camera3dBundle`.|
+|tonemapping_luts|Include tonemapping Look Up Tables KTX2 files. If everything is pink, you need to enable this feature or change the `Tonemapping` method for your `Camera2d` or `Camera3d`.|
 |vorbis|OGG/VORBIS audio format support|
 |webgl2|Enable some limitations to be able to use WebGL2. Please refer to the [WebGL2 and WebGPU](https://github.com/bevyengine/bevy/tree/latest/examples#webgl2-and-webgpu) section of the examples README for more information on how to run Wasm builds with WebGPU.|
 |x11|X11 display server support|