From f0c8f6453988701b69b4b79cf1bd10fc3d1f34af Mon Sep 17 00:00:00 2001
From: Jan Hohenheim <jan@hohenheim.ch>
Date: Wed, 21 Aug 2024 03:43:07 +0200
Subject: [PATCH] Twiddle constants

---
 src/actor.rs                     | 20 ++++++++++++++------
 src/interaction/hold/simulate.rs | 15 +++++++++------
 2 files changed, 23 insertions(+), 12 deletions(-)

diff --git a/src/actor.rs b/src/actor.rs
index 13ce498..bdb9513 100644
--- a/src/actor.rs
+++ b/src/actor.rs
@@ -86,11 +86,18 @@ pub struct AvianPickupActor {
     /// `max(collider_radius, min_distance)`.\
     /// Default: 0.5 m
     pub min_distance: Scalar,
-    /// A number >= 0 that indicates how much easing will be applied to the
-    /// held prop's velocity when the actor is moving.\
-    /// A value of 0 means no smoothing, i.e. the prop perfectly follows the actor.\
-    /// Default: 1.4
-    pub easing: Scalar,
+    /// A number >= 0 that indicates how much exponential easing will be applied
+    /// to the held prop's velocity when the actor is moving.\
+    /// A value of 0 means no smoothing, i.e. the prop perfectly follows the
+    /// actor.\
+    /// Default: 1.3
+    pub linear_velocity_easing: Scalar,
+    /// A number >= 0 that indicates how much exponential easing will be applied
+    /// to the held prop's angular velocity when the actor is rotating.\
+    /// A value of 0 means no smoothing, i.e. the prop perfectly follows the
+    /// actor's point of view.\
+    /// Default: 1.7
+    pub angular_velocity_easing: Scalar,
 }
 
 #[derive(Debug, Clone, Copy, Hash, PartialEq, Eq, Component, Default, Reflect)]
@@ -124,7 +131,8 @@ impl Default for AvianPickupActor {
             max_mass: 35.0,
             pull_force: 100.0,
             min_distance: 0.5,
-            easing: 1.4,
+            linear_velocity_easing: 1.3,
+            angular_velocity_easing: 1.7,
         }
     }
 }
diff --git a/src/interaction/hold/simulate.rs b/src/interaction/hold/simulate.rs
index 7720c6e..7ba4888 100644
--- a/src/interaction/hold/simulate.rs
+++ b/src/interaction/hold/simulate.rs
@@ -19,11 +19,8 @@ pub(super) fn set_velocities(
     // so I reverted to this simpler version. If you need the original version,
     // check out the commit aa51b2bc4dbc52049476135ba146b3ba143b681a
     let dt = time.delta_seconds();
+    let inv_dt = dt.recip();
     for (shadow, holding, actor) in q_actor.iter_mut() {
-        // This is used for a bit of easing. We don't need to be careful about
-        // things like overshooting as we are in a fixed timestep.
-        // A damping factor of 0 means no easing.
-        let inv_dt = (dt * f32::exp(actor.easing)).recip();
         let prop = holding.0;
         // Safety: All props are rigid bodies, so they are guaranteed to have a
         // `Position`, `Rotation`, `LinearVelocity`, and `AngularVelocity`.
@@ -37,10 +34,16 @@ pub(super) fn set_velocities(
         let angle = if angle > PI { angle - TAU } else { angle };
         let delta_rotation_scaled_axis = axis * angle;
 
-        velocity.0 = (delta_position * inv_dt).clamp_length_max(shadow.max_speed);
+        // This is used for a bit of easing. We don't need to be careful about
+        // things like overshooting as we are in a fixed timestep.
+        // Negative because the dt is already inverted
+        let vel_ease = f32::exp(-actor.linear_velocity_easing);
+        velocity.0 = (delta_position * inv_dt * vel_ease).clamp_length_max(shadow.max_speed);
         velocity.0 = zero_if_near_zero(velocity.0);
 
-        angvel.0 = (delta_rotation_scaled_axis * inv_dt).clamp_length_max(shadow.max_angular);
+        let angvel_ease = f32::exp(-actor.angular_velocity_easing);
+        angvel.0 = (delta_rotation_scaled_axis * inv_dt * angvel_ease)
+            .clamp_length_max(shadow.max_angular);
         angvel.0 = zero_if_near_zero(angvel.0);
     }
 }