Fix compound collider

src/interaction/hold/update.rs

@@ -57,7 +57,7 @@ pub(super) fn update_object(
     )>,
 
     q_collider_ancestor: Query<&Children, With<AncestorMarker<ColliderMarker>>>,
-    q_collider: Query<(&Position, &Rotation, &Collider), Without<Sensor>>,
+    q_collider: Query<(&Transform, &Collider), Without<Sensor>>,
 ) {
     let max_error = 0.3048; // 12 inches in the source engine
     for (actor, _config, grab, _shadow, holding, actor_position, actor_rotation) in
@@ -77,9 +77,12 @@ pub(super) fn update_object(
         let _actor_to_prop_pitch = actor_pitch.clamp(clamp_pitch.min, clamp_pitch.max);
         let forward = Transform::from_rotation(actor_rotation.0).forward();
         let compound_collider =
-            rigid_body_compound_collider(prop, *actor_position, &q_collider_ancestor, &q_collider);
+            rigid_body_compound_collider(prop, &q_collider_ancestor, &q_collider);
+        let Some(compound_collider) = compound_collider else {
+            error!("Held prop does not have a collider in its hierarchy. Ignoring.");
+            continue;
+        };
         let radial = collide_get_extent(&compound_collider, Vec3::ZERO, prop_rotation.0, -forward);
-        info!("radial: {:?}", radial);
 
         let _target_rotation = preferred_rotation
             .map(|preferred| preferred.0)
@@ -92,18 +95,19 @@ pub(super) fn update_object(
 /// but we can only do that for convex shapes in parry. Notably, compound shapes
 /// made of convex shapes are not supported.\
 /// So, we instead just cast a ray in the direction and get the hit point.
+/// Since the original code multiplies the directoin by the dot product of
+/// the direction and the support point, it looks like the result is the same.
 fn collide_get_extent(collider: &Collider, origin: Vec3, rotation: Quat, dir: Dir3) -> Vec3 {
     const TRANSLATION: Vec3 = Vec3::ZERO;
     // We cast from inside the collider, so we don't care about a max TOI
     const MAX_TOI: f32 = f32::INFINITY;
     // Needs to be false to not just get the origin back
     const SOLID: bool = false;
-    info!(
-        "translation: {:?}, rotation: {:?}, origin: {:?}, dir: {:?}",
-        TRANSLATION, rotation, origin, dir
-    );
-    info!("collider: {:?}", collider);
     let hit = collider.cast_ray(TRANSLATION, rotation, origin, dir.into(), MAX_TOI, SOLID);
-    let (toi, _normal) = hit.expect("Casting a ray from inside a collider did not hit the collider itself. This seems like a bug in Avian.");
+    let (toi, _normal) = hit.expect(
+        "Casting a ray from inside a collider did not hit the collider itself.\n\
+        This means the compound collider we constructed is malformed.\n\
+        This is a bug. Please report it on `avian_pickup`s GitHub page.",
+    );
     dir * toi
 }

src/math.rs

@@ -1,36 +1,42 @@
 use avian3d::{prelude::*, sync::ancestor_marker::AncestorMarker};
 use bevy::prelude::*;
-use dynamics::rigid_body;
 
 pub(crate) const METERS_PER_INCH: f32 = 0.0254;
 
 pub(crate) fn rigid_body_compound_collider(
     rigid_body: Entity,
-    origin: Position,
     q_collider_ancestor: &Query<&Children, With<AncestorMarker<ColliderMarker>>>,
-    q_collider: &Query<(&Position, &Rotation, &Collider), Without<Sensor>>,
-) -> Collider {
+    q_collider: &Query<(&Transform, &Collider), Without<Sensor>>,
+) -> Option<Collider> {
     let mut colliders = Vec::new();
-    rigid_body_compound_collider_recursive(
-        rigid_body,
-        q_collider_ancestor,
-        q_collider,
-        &mut colliders,
-        origin,
-    );
-    Collider::compound(colliders)
+    if let Ok((&_transform, col)) = q_collider.get(rigid_body) {
+        colliders.push((Vec3::ZERO, Quat::IDENTITY, col.clone()));
+    }
+    if let Ok(children) = q_collider_ancestor.get(rigid_body) {
+        for child in children.iter() {
+            rigid_body_compound_collider_recursive(
+                *child,
+                q_collider_ancestor,
+                q_collider,
+                &mut colliders,
+            );
+        }
+    }
+    if colliders.is_empty() {
+        None
+    } else {
+        Some(Collider::compound(colliders))
+    }
 }
 
 fn rigid_body_compound_collider_recursive(
     candidate: Entity,
     q_collider_ancestor: &Query<&Children, With<AncestorMarker<ColliderMarker>>>,
-    q_collider: &Query<(&Position, &Rotation, &Collider), Without<Sensor>>,
-    colliders: &mut Vec<(Position, Rotation, Collider)>,
-    origin: Position,
+    q_collider: &Query<(&Transform, &Collider), Without<Sensor>>,
+    colliders: &mut Vec<(Vec3, Quat, Collider)>,
 ) {
-    if let Ok((&pos, &rot, col)) = q_collider.get(candidate) {
-        let pos = pos.0 - origin.0;
-        colliders.push((pos.into(), rot, col.clone()));
+    if let Ok((&transform, col)) = q_collider.get(candidate) {
+        colliders.push((transform.translation, transform.rotation, col.clone()));
     }
     if let Ok(children) = q_collider_ancestor.get(candidate) {
         for child in children.iter() {
@@ -39,7 +45,6 @@ fn rigid_body_compound_collider_recursive(
                 q_collider_ancestor,
                 q_collider,
                 colliders,
-                origin,
             );
         }
     }