Add RenderLayer support to UI cameras

This enables having different UI per camera. With #5225, this enables
having different interactive UIs per window. Although, to properly
complete this, the focus system will need to account for RenderLayer of
UI nodes.

Author: nicopap

crates/bevy_ui/src/entity.rs

@@ -8,7 +8,7 @@ use bevy_ecs::{bundle::Bundle, prelude::Component};
 use bevy_math::Vec2;
 use bevy_render::{
     camera::{DepthCalculation, OrthographicProjection, WindowOrigin},
-    view::Visibility,
+    view::{RenderLayers, Visibility},
 };
 use bevy_text::Text;
 use bevy_transform::prelude::{GlobalTransform, Transform};
@@ -32,6 +32,8 @@ pub struct NodeBundle {
     pub global_transform: GlobalTransform,
     /// Describes the visibility properties of the node
     pub visibility: Visibility,
+    /// The ui camera layers this node is visible in.
+    pub render_layers: RenderLayers,
 }
 
 /// A UI node that is an image
@@ -57,6 +59,8 @@ pub struct ImageBundle {
     pub global_transform: GlobalTransform,
     /// Describes the visibility properties of the node
     pub visibility: Visibility,
+    /// The ui camera layers this image is visible in.
+    pub render_layers: RenderLayers,
 }
 
 /// A UI node that is text
@@ -78,6 +82,8 @@ pub struct TextBundle {
     pub global_transform: GlobalTransform,
     /// Describes the visibility properties of the node
     pub visibility: Visibility,
+    /// The ui camera layers this text is visible in.
+    pub render_layers: RenderLayers,
 }
 
 impl Default for TextBundle {
@@ -91,6 +97,7 @@ impl Default for TextBundle {
             transform: Default::default(),
             global_transform: Default::default(),
             visibility: Default::default(),
+            render_layers: Default::default(),
         }
     }
 }
@@ -118,6 +125,8 @@ pub struct ButtonBundle {
     pub global_transform: GlobalTransform,
     /// Describes the visibility properties of the node
     pub visibility: Visibility,
+    /// The ui camera layers this button is visible in.
+    pub render_layers: RenderLayers,
 }
 
 /// Configuration for cameras related to UI.
@@ -135,6 +144,8 @@ pub struct UiCameraConfig {
     pub show_ui: bool,
     /// The position of the UI camera in UI space.
     pub position: Vec2,
+    /// The ui camera layers this camera can see.
+    pub ui_render_layers: RenderLayers,
     /// The projection data for the UI camera.
     ///
     /// The code relies on this not being set,
@@ -162,6 +173,7 @@ impl Default for UiCameraConfig {
         Self {
             show_ui: true,
             position: Vec2::ZERO,
+            ui_render_layers: Default::default(),
             projection: OrthographicProjection {
                 far: UI_CAMERA_FAR,
                 window_origin: WindowOrigin::BottomLeft,

crates/bevy_ui/src/render/mod.rs

@@ -20,7 +20,7 @@ use bevy_render::{
     render_resource::*,
     renderer::{RenderDevice, RenderQueue},
     texture::Image,
-    view::{ExtractedView, ViewUniforms, Visibility},
+    view::{ExtractedView, RenderLayers, ViewUniforms, Visibility},
     RenderApp, RenderStage, RenderWorld,
 };
 use bevy_sprite::{Rect, SpriteAssetEvents, TextureAtlas};
@@ -166,6 +166,7 @@ pub struct ExtractedUiNode {
     pub image: Handle<Image>,
     pub atlas_size: Option<Vec2>,
     pub clip: Option<Rect>,
+    pub render_layers: RenderLayers,
 }
 
 #[derive(Default)]
@@ -182,12 +183,13 @@ pub fn extract_uinodes(
         &UiColor,
         &UiImage,
         &Visibility,
+        &RenderLayers,
         Option<&CalculatedClip>,
     )>,
 ) {
     let mut extracted_uinodes = render_world.resource_mut::<ExtractedUiNodes>();
     extracted_uinodes.uinodes.clear();
-    for (uinode, transform, color, image, visibility, clip) in uinode_query.iter() {
+    for (uinode, transform, color, image, visibility, render_layers, clip) in uinode_query.iter() {
         if !visibility.is_visible {
             continue;
         }
@@ -206,6 +208,7 @@ pub fn extract_uinodes(
             image,
             atlas_size: None,
             clip: clip.map(|clip| clip.clip),
+            render_layers: *render_layers,
         });
     }
 }
@@ -224,6 +227,7 @@ const UI_CAMERA_TRANSFORM_OFFSET: f32 = -0.1;
 #[derive(Component, Debug)]
 pub struct UiCamera {
     pub entity: Entity,
+    layers: RenderLayers,
 }
 
 pub fn extract_default_ui_camera_view<T: Component>(
@@ -260,7 +264,10 @@ pub fn extract_default_ui_camera_view<T: Component>(
                 height: physical_size.y,
             });
             commands.get_or_spawn(camera_entity).insert_bundle((
-                UiCamera { entity: ui_camera },
+                UiCamera {
+                    entity: ui_camera,
+                    layers: ui_config.ui_render_layers,
+                },
                 RenderPhase::<TransparentUi>::default(),
             ));
         }
@@ -278,14 +285,15 @@ pub fn extract_text_uinodes(
         &GlobalTransform,
         &Text,
         &Visibility,
+        &RenderLayers,
         Option<&CalculatedClip>,
     )>,
 ) {
     let mut extracted_uinodes = render_world.resource_mut::<ExtractedUiNodes>();
 
     let scale_factor = windows.scale_factor(WindowId::primary()) as f32;
 
-    for (entity, uinode, transform, text, visibility, clip) in uinode_query.iter() {
+    for (entity, uinode, transform, text, visibility, render_layers, clip) in uinode_query.iter() {
         if !visibility.is_visible {
             continue;
         }
@@ -321,6 +329,7 @@ pub fn extract_text_uinodes(
                     image: texture,
                     atlas_size,
                     clip: clip.map(|clip| clip.clip),
+                    render_layers: *render_layers,
                 });
             }
         }
@@ -358,8 +367,10 @@ const QUAD_VERTEX_POSITIONS: [Vec3; 4] = [
 
 const QUAD_INDICES: [usize; 6] = [0, 2, 3, 0, 1, 2];
 
+// Ui nodes are batches per image and per layer
 #[derive(Component)]
 pub struct UiBatch {
+    pub layers: RenderLayers,
     pub range: Range<u32>,
     pub image: Handle<Image>,
     pub z: f32,
@@ -382,20 +393,26 @@ pub fn prepare_uinodes(
     let mut start = 0;
     let mut end = 0;
     let mut current_batch_handle = Default::default();
+    let mut current_batch_layers = Default::default();
     let mut last_z = 0.0;
     for extracted_uinode in &extracted_uinodes.uinodes {
-        if current_batch_handle != extracted_uinode.image {
+        let same_layers = current_batch_layers == extracted_uinode.render_layers;
+        let same_handle = current_batch_handle == extracted_uinode.image;
+        if !same_handle || !same_layers {
             if start != end {
                 commands.spawn_bundle((UiBatch {
+                    layers: current_batch_layers,
                     range: start..end,
                     image: current_batch_handle,
                     z: last_z,
                 },));
                 start = end;
             }
+            current_batch_layers = extracted_uinode.render_layers;
             current_batch_handle = extracted_uinode.image.clone_weak();
         }
 
+        // TODO: the following code is hard to grasp, a refactor would be welcome :)
         let uinode_rect = extracted_uinode.rect;
         let rect_size = uinode_rect.size().extend(1.0);
 
@@ -473,14 +490,14 @@ pub fn prepare_uinodes(
                 color: extracted_uinode.color.as_linear_rgba_f32(),
             });
         }
-
         last_z = extracted_uinode.transform.w_axis[2];
         end += QUAD_INDICES.len() as u32;
     }
 
     // if start != end, there is one last batch to process
     if start != end {
         commands.spawn_bundle((UiBatch {
+            layers: current_batch_layers,
             range: start..end,
             image: current_batch_handle,
             z: last_z,
@@ -507,7 +524,7 @@ pub fn queue_uinodes(
     mut image_bind_groups: ResMut<UiImageBindGroups>,
     gpu_images: Res<RenderAssets<Image>>,
     ui_batches: Query<(Entity, &UiBatch)>,
-    mut views: Query<&mut RenderPhase<TransparentUi>>,
+    mut views: Query<(&mut RenderPhase<TransparentUi>, &UiCamera)>,
     events: Res<SpriteAssetEvents>,
 ) {
     // If an image has changed, the GpuImage has (probably) changed
@@ -531,8 +548,11 @@ pub fn queue_uinodes(
         }));
         let draw_ui_function = draw_functions.read().get_id::<DrawUi>().unwrap();
         let pipeline = pipelines.specialize(&mut pipeline_cache, &ui_pipeline, UiPipelineKey {});
-        for mut transparent_phase in views.iter_mut() {
+        for (mut transparent_phase, cam_data) in views.iter_mut() {
             for (entity, batch) in ui_batches.iter() {
+                if !batch.layers.intersects(&cam_data.layers) {
+                    continue;
+                }
                 image_bind_groups
                     .values
                     .entry(batch.image.clone_weak())

crates/bevy_ui/src/render/render_pass.rs

@@ -17,18 +17,18 @@ use bevy_render::{
 use bevy_utils::FloatOrd;
 
 pub struct UiPassNode {
-    ui_view_query:
+    view_query:
         QueryState<(&'static RenderPhase<TransparentUi>, &'static ViewTarget), With<ExtractedView>>,
-    default_camera_view_query: QueryState<&'static UiCamera>,
+    ui_camera_query: QueryState<&'static UiCamera>,
 }
 
 impl UiPassNode {
     pub const IN_VIEW: &'static str = "view";
 
     pub fn new(world: &mut World) -> Self {
         Self {
-            ui_view_query: world.query_filtered(),
-            default_camera_view_query: world.query(),
+            view_query: world.query_filtered(),
+            ui_camera_query: world.query(),
         }
     }
 }
@@ -39,8 +39,8 @@ impl Node for UiPassNode {
     }
 
     fn update(&mut self, world: &mut World) {
-        self.ui_view_query.update_archetypes(world);
-        self.default_camera_view_query.update_archetypes(world);
+        self.view_query.update_archetypes(world);
+        self.ui_camera_query.update_archetypes(world);
     }
 
     fn run(
@@ -49,10 +49,10 @@ impl Node for UiPassNode {
         render_context: &mut RenderContext,
         world: &World,
     ) -> Result<(), NodeRunError> {
-        let input_view_entity = graph.get_input_entity(Self::IN_VIEW)?;
+        let camera_view = graph.get_input_entity(Self::IN_VIEW)?;
 
         let (transparent_phase, target) =
-            if let Ok(result) = self.ui_view_query.get_manual(world, input_view_entity) {
+            if let Ok(result) = self.view_query.get_manual(world, camera_view) {
                 result
             } else {
                 return Ok(());
@@ -61,14 +61,12 @@ impl Node for UiPassNode {
         if transparent_phase.items.is_empty() {
             return Ok(());
         }
-        let view_entity = if let Ok(default_view) = self
-            .default_camera_view_query
-            .get_manual(world, input_view_entity)
-        {
-            default_view.entity
-        } else {
-            input_view_entity
-        };
+        let ui_view_entity =
+            if let Ok(ui_view) = self.ui_camera_query.get_manual(world, camera_view) {
+                ui_view.entity
+            } else {
+                return Ok(());
+            };
 
         let pass_descriptor = RenderPassDescriptor {
             label: Some("ui_pass"),
@@ -93,7 +91,7 @@ impl Node for UiPassNode {
         let mut tracked_pass = TrackedRenderPass::new(render_pass);
         for item in &transparent_phase.items {
             let draw_function = draw_functions.get_mut(item.draw_function).unwrap();
-            draw_function.draw(world, &mut tracked_pass, view_entity, item);
+            draw_function.draw(world, &mut tracked_pass, ui_view_entity, item);
         }
         Ok(())
     }

examples/window/multiple_windows.rs

@@ -2,7 +2,7 @@
 
 use bevy::{
     prelude::*,
-    render::camera::RenderTarget,
+    render::{camera::RenderTarget, view::RenderLayers},
     window::{CreateWindow, PresentMode, WindowId},
 };
 
@@ -30,10 +30,15 @@ fn setup(
         ..default()
     });
     // main camera
-    commands.spawn_bundle(Camera3dBundle {
-        transform: Transform::from_xyz(0.0, 0.0, 6.0).looking_at(Vec3::ZERO, Vec3::Y),
-        ..default()
-    });
+    commands
+        .spawn_bundle(Camera3dBundle {
+            transform: Transform::from_xyz(0.0, 0.0, 6.0).looking_at(Vec3::ZERO, Vec3::Y),
+            ..default()
+        })
+        .insert(UiCameraConfig {
+            ui_render_layers: RenderLayers::layer(1),
+            ..default()
+        });
 
     let window_id = WindowId::new();
 
@@ -50,12 +55,41 @@ fn setup(
     });
 
     // second window camera
-    commands.spawn_bundle(Camera3dBundle {
-        transform: Transform::from_xyz(6.0, 0.0, 0.0).looking_at(Vec3::ZERO, Vec3::Y),
-        camera: Camera {
-            target: RenderTarget::Window(window_id),
+    commands
+        .spawn_bundle(Camera3dBundle {
+            transform: Transform::from_xyz(6.0, 0.0, 0.0).looking_at(Vec3::ZERO, Vec3::Y),
+            camera: Camera {
+                target: RenderTarget::Window(window_id),
+                ..default()
+            },
             ..default()
-        },
+        })
+        .insert(UiCameraConfig {
+            ui_render_layers: RenderLayers::layer(2),
+            ..default()
+        });
+    let text_style = TextStyle {
+        font: asset_server.load("fonts/FiraSans-Bold.ttf"),
+        font_size: 100.0,
+        color: Color::WHITE,
+    };
+    let align = TextAlignment {
+        horizontal: HorizontalAlign::Center,
+        ..default()
+    };
+    commands.spawn_bundle(TextBundle {
+        text: Text::with_section("Face", text_style.clone(), align),
+        render_layers: RenderLayers::layer(1),
+        ..default()
+    });
+    commands.spawn_bundle(TextBundle {
+        text: Text::with_section("Profile", text_style.clone(), align),
+        render_layers: RenderLayers::layer(2),
+        ..default()
+    });
+    commands.spawn_bundle(TextBundle {
+        text: Text::with_section("view", text_style, align),
+        render_layers: RenderLayers::all(),
         ..default()
     });
 }