Add Viewport component to the camera bundles

Cameras are now decoupled from Windows, but automatic viewport resizing
isn't implemented yet.

crates/bevy_render/src/camera/camera.rs

@@ -1,10 +1,8 @@
-use super::CameraProjection;
-use bevy_app::prelude::EventReader;
-use bevy_ecs::{Added, Component, Entity, Query, QuerySet, Res};
+use super::{CameraProjection, Viewport};
+use bevy_ecs::{Changed, Component, Query};
 use bevy_math::{Mat4, Vec2, Vec3};
 use bevy_reflect::{Reflect, ReflectComponent, ReflectDeserialize};
 use bevy_transform::components::GlobalTransform;
-use bevy_window::{WindowCreated, WindowId, WindowResized, Windows};
 use serde::{Deserialize, Serialize};
 
 #[derive(Default, Debug, Reflect)]
@@ -13,8 +11,6 @@ pub struct Camera {
     pub projection_matrix: Mat4,
     pub name: Option<String>,
     #[reflect(ignore)]
-    pub window: WindowId,
-    #[reflect(ignore)]
     pub depth_calculation: DepthCalculation,
 }
 
@@ -37,12 +33,10 @@ impl Camera {
     /// Given a position in world space, use the camera to compute the screen space coordinates.
     pub fn world_to_screen(
         &self,
-        windows: &Windows,
+        viewport: &Viewport,
         camera_transform: &GlobalTransform,
         world_position: Vec3,
     ) -> Option<Vec2> {
-        let window = windows.get(self.window)?;
-        let window_size = Vec2::new(window.width(), window.height());
         // Build a transform to convert from world to NDC using camera data
         let world_to_ndc: Mat4 =
             self.projection_matrix * camera_transform.compute_matrix().inverse();
@@ -52,50 +46,22 @@ impl Camera {
             return None;
         }
         // Once in NDC space, we can discard the z element and rescale x/y to fit the screen
-        let screen_space_coords = (ndc_space_coords.truncate() + Vec2::one()) / 2.0 * window_size;
+        let screen_space_coords =
+            viewport.origin + (ndc_space_coords.truncate() + Vec2::one()) / 2.0 * viewport.size;
         Some(screen_space_coords)
     }
 }
 
 pub fn camera_system<T: CameraProjection + Component>(
-    mut window_resized_events: EventReader<WindowResized>,
-    mut window_created_events: EventReader<WindowCreated>,
-    windows: Res<Windows>,
-    mut queries: QuerySet<(
-        Query<(Entity, &mut Camera, &mut T)>,
-        Query<Entity, Added<Camera>>,
-    )>,
+    mut query: Query<(&mut Camera, &mut T, &Viewport), Changed<Viewport>>,
 ) {
-    let mut changed_window_ids = Vec::new();
-    // handle resize events. latest events are handled first because we only want to resize each window once
-    for event in window_resized_events.iter().rev() {
-        if changed_window_ids.contains(&event.id) {
-            continue;
-        }
-
-        changed_window_ids.push(event.id);
-    }
-
-    // handle resize events. latest events are handled first because we only want to resize each window once
-    for event in window_created_events.iter().rev() {
-        if changed_window_ids.contains(&event.id) {
-            continue;
-        }
-
-        changed_window_ids.push(event.id);
-    }
-
-    let mut added_cameras = vec![];
-    for entity in &mut queries.q1().iter() {
-        added_cameras.push(entity);
-    }
-    for (entity, mut camera, mut camera_projection) in queries.q0_mut().iter_mut() {
-        if let Some(window) = windows.get(camera.window) {
-            if changed_window_ids.contains(&window.id()) || added_cameras.contains(&entity) {
-                camera_projection.update(window.width(), window.height());
-                camera.projection_matrix = camera_projection.get_projection_matrix();
-                camera.depth_calculation = camera_projection.depth_calculation();
-            }
-        }
+    for (mut camera, mut camera_projection, viewport) in query.iter_mut() {
+        println!(
+            "updating camera {:?}, vp {}x{} at {}x{}",
+            camera.name, viewport.size.x, viewport.size.y, viewport.origin.x, viewport.origin.y
+        );
+        camera_projection.update(viewport.size.x, viewport.size.y);
+        camera.projection_matrix = camera_projection.get_projection_matrix();
+        camera.depth_calculation = camera_projection.depth_calculation();
     }
 }

crates/bevy_render/src/camera/mod.rs

@@ -2,9 +2,11 @@ mod active_cameras;
 #[allow(clippy::module_inception)]
 mod camera;
 mod projection;
+mod viewport;
 mod visible_entities;
 
 pub use active_cameras::*;
 pub use camera::*;
 pub use projection::*;
+pub use viewport::*;
 pub use visible_entities::*;

crates/bevy_render/src/camera/viewport.rs

@@ -0,0 +1,22 @@
+use bevy_math::Vec2;
+use bevy_reflect::{Reflect, ReflectComponent};
+
+#[derive(Debug, PartialEq, Clone, Reflect)]
+#[reflect(Component)]
+pub struct Viewport {
+    pub name: Option<String>,
+    pub origin: Vec2,
+    pub size: Vec2,
+    pub scale_factor: f64,
+}
+
+impl Default for Viewport {
+    fn default() -> Self {
+        Self {
+            name: None,
+            origin: Vec2::zero(),
+            size: Vec2::one(),
+            scale_factor: 1.0,
+        }
+    }
+}

crates/bevy_render/src/entity.rs

@@ -1,7 +1,7 @@
 use crate::{
     camera::{
         Camera, DepthCalculation, OrthographicProjection, PerspectiveProjection, ScalingMode,
-        VisibleEntities,
+        Viewport, VisibleEntities,
     },
     pipeline::RenderPipelines,
     prelude::Visible,
@@ -32,6 +32,7 @@ pub struct MeshBundle {
 pub struct PerspectiveCameraBundle {
     pub camera: Camera,
     pub perspective_projection: PerspectiveProjection,
+    pub viewport: Viewport,
     pub visible_entities: VisibleEntities,
     pub transform: Transform,
     pub global_transform: GlobalTransform,
@@ -49,6 +50,7 @@ impl PerspectiveCameraBundle {
                 ..Default::default()
             },
             perspective_projection: Default::default(),
+            viewport: Default::default(),
             visible_entities: Default::default(),
             transform: Default::default(),
             global_transform: Default::default(),
@@ -64,6 +66,7 @@ impl Default for PerspectiveCameraBundle {
                 ..Default::default()
             },
             perspective_projection: Default::default(),
+            viewport: Default::default(),
             visible_entities: Default::default(),
             transform: Default::default(),
             global_transform: Default::default(),
@@ -78,6 +81,7 @@ impl Default for PerspectiveCameraBundle {
 pub struct OrthographicCameraBundle {
     pub camera: Camera,
     pub orthographic_projection: OrthographicProjection,
+    pub viewport: Viewport,
     pub visible_entities: VisibleEntities,
     pub transform: Transform,
     pub global_transform: GlobalTransform,
@@ -98,6 +102,7 @@ impl OrthographicCameraBundle {
                 depth_calculation: DepthCalculation::ZDifference,
                 ..Default::default()
             },
+            viewport: Default::default(),
             visible_entities: Default::default(),
             transform: Transform::from_xyz(0.0, 0.0, far - 0.1),
             global_transform: Default::default(),
@@ -115,6 +120,7 @@ impl OrthographicCameraBundle {
                 depth_calculation: DepthCalculation::Distance,
                 ..Default::default()
             },
+            viewport: Default::default(),
             visible_entities: Default::default(),
             transform: Default::default(),
             global_transform: Default::default(),
@@ -128,6 +134,7 @@ impl OrthographicCameraBundle {
                 ..Default::default()
             },
             orthographic_projection: Default::default(),
+            viewport: Default::default(),
             visible_entities: Default::default(),
             transform: Default::default(),
             global_transform: Default::default(),

crates/bevy_render/src/render_graph/nodes/pass_node.rs

@@ -1,5 +1,5 @@
 use crate::{
-    camera::{ActiveCameras, VisibleEntities},
+    camera::{ActiveCameras, Viewport, VisibleEntities},
     draw::{Draw, RenderCommand},
     pass::{ClearColor, LoadOp, PassDescriptor, TextureAttachment},
     pipeline::{
@@ -216,13 +216,26 @@ where
                         continue;
                     };
 
-                    // get an ordered list of entities visible to the camera
-                    let visible_entities = if let Some(camera_entity) = active_cameras.get(&camera_info.name) {
-                        world.get::<VisibleEntities>(camera_entity).unwrap()
+                    let camera_entity = if let Some(camera_entity) = active_cameras.get(&camera_info.name) {
+                        camera_entity
                     } else {
                         continue;
                     };
 
+                    // get an ordered list of entities visible to the camera
+                    let visible_entities = world.get::<VisibleEntities>(camera_entity).unwrap();
+
+                    // get camera viewport and apply it
+                    let viewport = world.get::<Viewport>(camera_entity).unwrap();
+                    render_pass.set_viewport(
+                        viewport.origin.x,
+                        viewport.origin.y,
+                        viewport.size.x,
+                        viewport.size.y,
+                        // TODO: implement min/max depth
+                        0.0, 1.0,
+                    );
+
                     // attempt to draw each visible entity
                     let mut draw_state = DrawState::default();
                     for visible_entity in visible_entities.iter() {

crates/bevy_ui/src/entity.rs

@@ -7,7 +7,9 @@ use crate::{
 use bevy_asset::Handle;
 use bevy_ecs::Bundle;
 use bevy_render::{
-    camera::{Camera, DepthCalculation, OrthographicProjection, VisibleEntities, WindowOrigin},
+    camera::{
+        Camera, DepthCalculation, OrthographicProjection, Viewport, VisibleEntities, WindowOrigin,
+    },
     draw::Draw,
     mesh::Mesh,
     pipeline::{RenderPipeline, RenderPipelines},
@@ -167,6 +169,7 @@ impl Default for ButtonBundle {
 pub struct UiCameraBundle {
     pub camera: Camera,
     pub orthographic_projection: OrthographicProjection,
+    pub viewport: Viewport,
     pub visible_entities: VisibleEntities,
     pub transform: Transform,
     pub global_transform: GlobalTransform,
@@ -189,6 +192,7 @@ impl Default for UiCameraBundle {
                 ..Default::default()
             },
             visible_entities: Default::default(),
+            viewport: Default::default(),
             transform: Transform::from_xyz(0.0, 0.0, far - 0.1),
             global_transform: Default::default(),
         }