Update Activate example with status text (#315)

Update the `activate.rs` example to add a text showing the `Spawner`
status, and a `KillAabbModifier` to constraint particles inside the
water.

.github/workflows/ci.yaml

@@ -123,19 +123,19 @@ jobs:
           for example in .github/example-run/3d/*.ron; do
             example_name=`basename $example .ron`
             echo "running $example_name - "`date`
-            time CI_TESTING_CONFIG=$example xvfb-run cargo run --example $example_name --no-default-features --features="bevy/bevy_winit bevy/bevy_pbr 3d bevy/bevy_ci_testing"
+            time CI_TESTING_CONFIG=$example xvfb-run cargo run --example $example_name --no-default-features --features="bevy/bevy_winit bevy/bevy_pbr bevy/bevy_ui bevy/default_font 3d bevy/bevy_ci_testing"
             sleep 10
           done
           for example in .github/example-run/3dpng/*.ron; do
             example_name=`basename $example .ron`
             echo "running $example_name - "`date`
-            time CI_TESTING_CONFIG=$example xvfb-run cargo run --example $example_name --no-default-features --features="bevy/bevy_winit bevy/bevy_pbr bevy/png 3d bevy/bevy_ci_testing"
+            time CI_TESTING_CONFIG=$example xvfb-run cargo run --example $example_name --no-default-features --features="bevy/bevy_winit bevy/bevy_pbr bevy/bevy_ui bevy/default_font bevy/png 3d bevy/bevy_ci_testing"
             sleep 10
           done
           for example in .github/example-run/2d/*.ron; do
             example_name=`basename $example .ron`
             echo "running $example_name - "`date`
-            time CI_TESTING_CONFIG=$example xvfb-run cargo run --example $example_name --no-default-features --features="bevy/bevy_winit bevy/bevy_sprite 2d bevy/bevy_ci_testing"
+            time CI_TESTING_CONFIG=$example xvfb-run cargo run --example $example_name --no-default-features --features="bevy/bevy_winit bevy/bevy_sprite bevy/bevy_ui bevy/default_font 2d bevy/bevy_ci_testing"
             sleep 10
           done
         env:

Cargo.toml

@@ -110,7 +110,7 @@ required-features = [ "bevy/bevy_winit", "bevy/bevy_pbr", "3d" ]
 
 [[example]]
 name = "activate"
-required-features = [ "bevy/bevy_winit", "bevy/bevy_pbr", "3d" ]
+required-features = [ "bevy/bevy_winit", "bevy/bevy_pbr", "bevy/bevy_ui", "bevy/default_font", "3d" ]
 
 [[example]]
 name = "force_field"

README.md

@@ -202,7 +202,7 @@ cargo run --example multicam --features="bevy/bevy_winit bevy/bevy_pbr 3d"
 
 ### Activate
 
-This example demonstrates manual activation and deactivation of a spawner, from code (CPU). The circle bobs up and down in the water, spawning square bubbles when in the water only.
+This example demonstrates manual activation and deactivation of a `Spawner`, from code (CPU). The circle bobs up and down in the water, spawning bubbles when in the water only. The bubble particles are constrained to the water with a `KillAabbModifier`, and a small vertical acceleration simulate some pseudo buoyancy.
 
 ```shell
 cargo run --example activate --features="bevy/bevy_winit bevy/bevy_pbr 3d"

examples/activate.rs

@@ -1,10 +1,14 @@
-//! A circle bobs up and down in the water, spawning square bubbles when in the
-//! water.
+//! A circle bobs up and down in the water, spawning bubbles when in the water.
 //!
 //! This example demonstrates the use of [`Spawner::set_active()`] to enable or
 //! disable particle spawning, under the control of the application. This is
 //! similar to the `spawn_on_command.rs` example, where [`Spawner::reset()`] is
 //! used instead to spawn a single burst of particles.
+//!
+//! A small vertical acceleration simulate a pseudo-buoyancy making the bubbles
+//! slowly move upward toward the surface. The example uses a
+//! [`KillAabbModifier`] to ensure the bubble particles never escape water, and
+//! are despawned when reaching the surface.
 
 use bevy::{
     core_pipeline::tonemapping::Tonemapping,
@@ -58,6 +62,9 @@ fn main() -> Result<(), Box<dyn std::error::Error>> {
     Ok(())
 }
 
+#[derive(Component)]
+struct StatusText;
+
 #[derive(Component)]
 struct Ball {
     velocity_y: f32,
@@ -80,6 +87,7 @@ fn setup(
     camera.projection = Projection::Orthographic(projection);
     commands.spawn(camera);
 
+    // Blue rectangle mesh for "water"
     commands
         .spawn(PbrBundle {
             mesh: meshes.add(Rectangle {
@@ -132,6 +140,14 @@ fn setup(
         speed: writer.lit(0.1).expr(),
     };
 
+    let buoyancy = writer.lit(Vec3::Y * 0.2).expr();
+    let update_buoyancy = AccelModifier::new(buoyancy);
+
+    // Kill particles getting out of water
+    let center = writer.lit(Vec3::Y * -2.02).expr();
+    let half_size = writer.lit(Vec3::splat(2.0)).expr();
+    let allow_zone = KillAabbModifier::new(center, half_size);
+
     let mut module = writer.finish();
 
     let round = RoundModifier::constant(&mut module, 1.0);
@@ -143,9 +159,10 @@ fn setup(
             .init(init_vel)
             .init(init_age)
             .init(init_lifetime)
-            .render(SizeOverLifetimeModifier {
-                gradient: Gradient::constant(Vec2::splat(0.02)),
-                screen_space_size: false,
+            .update(update_buoyancy)
+            .update(allow_zone)
+            .render(SetSizeModifier {
+                size: Vec2::splat(0.02).into(),
             })
             .render(ColorOverLifetimeModifier { gradient })
             .render(round),
@@ -155,11 +172,33 @@ fn setup(
         node.spawn(ParticleEffectBundle::new(effect))
             .insert(Name::new("effect"));
     });
+
+    commands.spawn((
+        TextBundle {
+            style: Style {
+                position_type: PositionType::Absolute,
+                top: Val::Px(30.),
+                right: Val::Px(30.),
+                ..default()
+            },
+            text: Text::from_section(
+                "Active",
+                TextStyle {
+                    font_size: 60.0,
+                    color: Color::WHITE,
+                    ..default()
+                },
+            ),
+            ..default()
+        },
+        StatusText,
+    ));
 }
 
 fn update(
     mut q_balls: Query<(&mut Ball, &mut Transform, &Children)>,
     mut q_spawner: Query<&mut EffectSpawner>,
+    mut q_text: Query<&mut Text, With<StatusText>>,
     time: Res<Time>,
 ) {
     const ACCELERATION: f32 = 1.0;
@@ -175,8 +214,12 @@ fn update(
         // Note: On first frame where the effect spawns, EffectSpawner is spawned during
         // CoreSet::PostUpdate, so will not be available yet. Ignore for a frame
         // if so.
+        let is_active = transform.translation.y < 0.0;
         if let Ok(mut spawner) = q_spawner.get_mut(children[0]) {
-            spawner.set_active(transform.translation.y < 0.0);
+            spawner.set_active(is_active);
         }
+
+        let mut text = q_text.single_mut();
+        text.sections[0].value = (if is_active { "Active" } else { "Inactive" }).to_string();
     }
 }

run_examples.bat

@@ -9,7 +9,7 @@ cargo r --example multicam --no-default-features --features="bevy/bevy_winit bev
 cargo r --example visibility --no-default-features --features="bevy/bevy_winit bevy/bevy_pbr 3d examples_world_inspector"
 cargo r --example random --no-default-features --features="bevy/bevy_winit bevy/bevy_pbr 3d examples_world_inspector"
 cargo r --example spawn_on_command --no-default-features --features="bevy/bevy_winit bevy/bevy_pbr 3d examples_world_inspector"
-cargo r --example activate --no-default-features --features="bevy/bevy_winit bevy/bevy_pbr 3d examples_world_inspector"
+cargo r --example activate --no-default-features --features="bevy/bevy_winit bevy/bevy_pbr bevy/bevy_ui bevy/default_font 3d examples_world_inspector"
 cargo r --example force_field --no-default-features --features="bevy/bevy_winit bevy/bevy_pbr 3d examples_world_inspector"
 cargo r --example init --no-default-features --features="bevy/bevy_winit bevy/bevy_pbr 3d examples_world_inspector"
 cargo r --example lifetime --no-default-features --features="bevy/bevy_winit bevy/bevy_pbr 3d examples_world_inspector"

run_examples.sh

@@ -8,7 +8,7 @@ cargo r --example multicam --no-default-features --features="bevy/bevy_winit bev
 cargo r --example visibility --no-default-features --features="bevy/bevy_winit bevy/bevy_pbr 3d examples_world_inspector"
 cargo r --example random --no-default-features --features="bevy/bevy_winit bevy/bevy_pbr 3d examples_world_inspector"
 cargo r --example spawn_on_command --no-default-features --features="bevy/bevy_winit bevy/bevy_pbr 3d examples_world_inspector"
-cargo r --example activate --no-default-features --features="bevy/bevy_winit bevy/bevy_pbr 3d examples_world_inspector"
+cargo r --example activate --no-default-features --features="bevy/bevy_winit bevy/bevy_pbr bevy/bevy_ui bevy/default_font 3d examples_world_inspector"
 cargo r --example force_field --no-default-features --features="bevy/bevy_winit bevy/bevy_pbr 3d examples_world_inspector"
 cargo r --example init --no-default-features --features="bevy/bevy_winit bevy/bevy_pbr 3d examples_world_inspector"
 cargo r --example lifetime --no-default-features --features="bevy/bevy_winit bevy/bevy_pbr 3d examples_world_inspector"