Feat/cloth inflator

CHANGELOG.md

@@ -19,6 +19,7 @@
 
 With the new version (See [Migration guide](https://github.com/jakobhellermann/bevy-inspector-egui/blob/main/docs/MIGRATION_GUIDE_0.15_0.16.md)),
 the following changes were applied:
+
 * (**BREAKING**) Removed `debug` feature
 * Removed `bevy_inspector_egui` dependency, kept only as `dev-dependency` for examples
 

Cargo.toml

@@ -58,6 +58,11 @@ default-features = false
 name = "balloon"
 path = "examples/balloon_example.rs"
 
+[[example]]
+name = "bouncy_balloon"
+path = "examples/bouncy_balloon_example.rs"
+required-features = ["rapier_collisions"]
+
 [[example]]
 name = "flag"
 path = "examples/flag_example.rs"

README.md

@@ -286,5 +286,9 @@ run `cargo run --example rapier_collision --features rapier_collisions`
 
 run `cargo run --example anchors`
 
+6. Bouncy ballon
+
+run `cargo run --example bouncy_balloon --features rapier_collisions`
+
 [Rapier]: https://github.com/dimforge/bevy_rapier
 [Heron]: https://github.com/jcornaz/heron

examples/bouncy_balloon_example.rs

@@ -0,0 +1,76 @@
+use bevy::prelude::*;
+use bevy_inspector_egui::quick::{ResourceInspectorPlugin, WorldInspectorPlugin};
+use bevy_rapier3d::prelude::*;
+use bevy_silk::prelude::*;
+
+mod camera_plugin;
+
+fn main() {
+    App::new()
+        .insert_resource(AmbientLight {
+            color: Color::WHITE,
+            brightness: 1.0,
+        })
+        .add_plugins(DefaultPlugins)
+        .add_plugins(WorldInspectorPlugin::new())
+        .add_plugins(RapierPhysicsPlugin::<NoUserData>::default())
+        .add_plugins(RapierDebugRenderPlugin::default())
+        .add_plugins(ResourceInspectorPlugin::<ClothConfig>::new())
+        .add_plugins(camera_plugin::CameraPlugin)
+        .add_plugins(ClothPlugin)
+        .insert_resource(ClothConfig {
+            ..Default::default()
+        })
+        .add_systems(Startup, (spawn_cloth, setup))
+        .run();
+}
+
+fn setup(
+    mut commands: Commands,
+    mut materials: ResMut<Assets<StandardMaterial>>,
+    mut meshes: ResMut<Assets<Mesh>>,
+) {
+    commands.spawn(DirectionalLightBundle::default());
+    let mesh = meshes.add(shape::Cube::new(50.0).into());
+
+    // Ground
+    commands.spawn((
+        PbrBundle {
+            mesh,
+            material: materials.add(Color::WHITE.into()),
+            transform: Transform::from_xyz(0.0, -20.0, 0.0),
+            ..Default::default()
+        },
+        Name::new("Ground"),
+        Collider::cuboid(25.0, 25.0, 25.0),
+    ));
+}
+
+fn spawn_cloth(
+    mut commands: Commands,
+    mut materials: ResMut<Assets<StandardMaterial>>,
+    mut meshes: ResMut<Assets<Mesh>>,
+) {
+    commands.spawn((
+        PbrBundle {
+            mesh: meshes.add(
+                shape::Icosphere {
+                    radius: 5.0,
+                    subdivisions: 10,
+                }
+                .try_into()
+                .unwrap(),
+            ),
+            material: materials.add(Color::YELLOW.into()),
+            transform: Transform::from_xyz(0.0, 15.0, 0.0),
+            ..Default::default()
+        },
+        ClothBuilder::new(),
+        ClothInflator::new(0.7),
+        ClothCollider {
+            velocity_coefficient: 2.0,
+            ..default()
+        },
+        Name::new("Balloon"),
+    ));
+}

src/components/cloth_inflator.rs

@@ -0,0 +1,76 @@
+use crate::components::cloth::StickId;
+use crate::prelude::{StickMode, VertexAnchor};
+use bevy::ecs::prelude::Component;
+use bevy::math::Vec3;
+use bevy::reflect::Reflect;
+
+/// Cloth inflator center selection mode
+#[derive(Debug, Default, Copy, Clone, Reflect)]
+pub enum InflatorCenter {
+    #[default]
+    /// The center of the mesh bounding box will be selected
+    Aabb,
+    /// A custom local center
+    Custom(Vec3),
+}
+
+/// Cloth Inflator component. Allows to simulate inflating a cloth mesh.
+///
+/// This component will add an extra *centroid* point to the cloth and as many spring
+/// sticks as there are points (vertice) on the cloth.
+/// Pleas not that this is not an actual soft body simulation, but a very approximated
+/// version using the verlet integration engine
+#[derive(Debug, Default, Clone, Component, Reflect)]
+pub struct ClothInflator {
+    /// Target minimal inflating amount
+    /// - `0.0` would mean no inflating
+    /// - `1.0` would mean *full* inflating
+    pub inflating_percent: f32,
+    /// The inflating center. This will be applied only once
+    pub(crate) center: InflatorCenter,
+    /// Optional anchor for the added center point
+    pub(crate) anchor: Option<VertexAnchor>,
+    /// The cloth sticks behaviours to edit
+    #[reflect(ignore)]
+    pub(crate) sticks: Vec<StickId>,
+}
+
+impl ClothInflator {
+    /// Instantiates a new inflator with the given `min_volume`
+    #[inline]
+    #[must_use]
+    pub const fn new(inflating_percent: f32) -> Self {
+        Self {
+            inflating_percent,
+            center: InflatorCenter::Aabb,
+            anchor: None,
+            sticks: vec![],
+        }
+    }
+
+    /// Defines a custom local space center instead of the default Aabb center
+    #[inline]
+    #[must_use]
+    pub const fn with_custom_center(mut self, center: Vec3) -> Self {
+        self.center = InflatorCenter::Custom(center);
+        self
+    }
+
+    /// Defines a vertex anchor for the new cloth point
+    #[inline]
+    #[must_use]
+    pub const fn with_anchor(mut self, anchor: VertexAnchor) -> Self {
+        self.anchor = Some(anchor);
+        self
+    }
+
+    #[inline]
+    #[must_use]
+    /// Computes the stick behaviour mode of the inflator
+    pub(crate) fn stick_mode(&self) -> StickMode {
+        StickMode::Spring {
+            min_percent: self.inflating_percent.max(0.1),
+            max_percent: f32::MAX,
+        }
+    }
+}

src/components/mod.rs

@@ -2,6 +2,8 @@
 pub mod cloth;
 /// cloth builder module
 pub mod cloth_builder;
+/// Cloth inflator module
+pub mod cloth_inflator;
 /// cloth rendering module
 pub mod cloth_rendering;
 /// collider module

src/lib.rs

@@ -285,6 +285,7 @@ pub mod prelude {
     pub use crate::components::collider::ClothCollider;
     pub use crate::{
         components::cloth_builder::ClothBuilder,
+        components::cloth_inflator::ClothInflator,
         components::cloth_rendering::NormalComputing,
         config::{AccelerationSmoothing, ClothConfig},
         error::Error,
@@ -306,12 +307,18 @@ impl Plugin for ClothPlugin {
         app.register_type::<ClothConfig>()
             .register_type::<Wind>()
             .register_type::<Winds>()
-            .register_type::<ClothBuilder>();
+            .register_type::<ClothBuilder>()
+            .register_type::<ClothInflator>();
         app.add_systems(
             Update,
             (
                 systems::cloth::init,
-                (systems::cloth::update, systems::cloth::render).chain(),
+                (
+                    systems::cloth::inflate,
+                    systems::cloth::update,
+                    systems::cloth::render,
+                )
+                    .chain(),
             ),
         );
         #[cfg(feature = "rapier_collisions")]

src/systems/cloth.rs

@@ -6,6 +6,7 @@
 
 use crate::components::cloth::Cloth;
 use crate::components::cloth_builder::ClothBuilder;
+use crate::components::cloth_inflator::{ClothInflator, InflatorCenter};
 use crate::components::cloth_rendering::ClothRendering;
 use crate::config::ClothConfig;
 use crate::wind::Winds;
@@ -41,6 +42,12 @@ pub fn update(
     }
 }
 
+pub fn inflate(mut query: Query<(&mut Cloth, &ClothInflator), Changed<ClothInflator>>) {
+    for (mut cloth, inflator) in query.iter_mut() {
+        cloth.edit_stick_modes(&inflator.sticks, inflator.stick_mode());
+    }
+}
+
 pub fn render(
     mut cloth_query: Query<(
         &Cloth,
@@ -64,16 +71,25 @@ pub fn render(
 
 pub fn init(
     mut commands: Commands,
-    mut query: Query<(Entity, &ClothBuilder, &GlobalTransform, &Handle<Mesh>), Added<ClothBuilder>>,
+    mut query: Query<
+        (
+            Entity,
+            &ClothBuilder,
+            &GlobalTransform,
+            &Handle<Mesh>,
+            Option<&mut ClothInflator>,
+        ),
+        Added<ClothBuilder>,
+    >,
     meshes: Res<Assets<Mesh>>,
 ) {
-    for (entity, builder, transform, handle) in query.iter_mut() {
+    for (entity, builder, transform, handle, inflator) in query.iter_mut() {
         if let Some(mesh) = meshes.get(handle) {
             let matrix = transform.compute_matrix();
             log::debug!("Initializing Cloth entity {:?}", entity);
             let rendering = ClothRendering::init(mesh, builder.normals_computing).unwrap();
             let aabb = rendering.compute_aabb();
-            let cloth = Cloth::new(
+            let mut cloth = Cloth::new(
                 &rendering.vertex_positions,
                 &rendering.indices,
                 builder.anchored_vertex_ids(mesh),
@@ -82,6 +98,20 @@ pub fn init(
                 builder.default_stick_mode,
                 &matrix,
             );
+            if let Some(mut inflator) = inflator {
+                let center = match inflator.center {
+                    InflatorCenter::Aabb => aabb.center.into(),
+                    InflatorCenter::Custom(c) => c,
+                };
+                let (_, sticks) = cloth.add_point(
+                    center,
+                    inflator.stick_mode(),
+                    inflator.anchor,
+                    &matrix,
+                    |_, _| true,
+                );
+                inflator.sticks = sticks;
+            }
             commands.entity(entity).insert((rendering, cloth, aabb));
         }
     }