forces

src/forces.rs

@@ -0,0 +1,35 @@
+use std::any::TypeId;
+
+use bevy::prelude::*;
+use bevy_rapier3d::prelude::ExternalForce;
+use indexmap::IndexMap;
+
+#[derive(Component, Default)]
+pub struct ExternalForceSet {
+    forces: IndexMap<TypeId, ExternalForce, ahash::RandomState>,
+}
+
+impl ExternalForceSet {
+    pub fn get<T: 'static>(&self) -> ExternalForce {
+        self.forces
+            .get(&TypeId::of::<T>())
+            .copied()
+            .unwrap_or_default()
+    }
+
+    pub fn set<T: 'static>(&mut self, force: ExternalForce) {
+        self.forces.insert(TypeId::of::<T>(), force);
+    }
+
+    fn combine(&self) -> ExternalForce {
+        self.forces
+            .values()
+            .fold(ExternalForce::default(), |f1, &f2| f1 + f2)
+    }
+}
+
+pub fn update_external_forces(mut query: Query<(&mut ExternalForce, &ExternalForceSet)>) {
+    for (mut force, forces) in &mut query {
+        *force = forces.combine();
+    }
+}