From 6a3e244f5e6191a71fe2cea92c6b41d933c5beef Mon Sep 17 00:00:00 2001
From: rewin <rewin1996@gmail.com>
Date: Sat, 9 Dec 2023 15:08:18 +0300
Subject: [PATCH] Air resistance for walk controller (more realistic stopping
 behaviour)

---
 src/physics.rs  | 8 +++++---
 src/shepherd.rs | 4 ++--
 2 files changed, 7 insertions(+), 5 deletions(-)

diff --git a/src/physics.rs b/src/physics.rs
index 3a55f9a..3513719 100644
--- a/src/physics.rs
+++ b/src/physics.rs
@@ -4,6 +4,8 @@ use crate::GameSet;
 
 pub struct PhysicsPlugin;
 
+const AIR_RESISTANCE: f32 = 0.5;
+
 impl Plugin for PhysicsPlugin {
     fn build(&self, app: &mut App) {
         app.add_systems(
@@ -32,11 +34,11 @@ pub struct WalkController {
 }
 
 fn walk_system(time: Res<Time>, mut query: Query<(&mut Velocity, &mut WalkController)>) {
-    for (mut velocity, controller) in query.iter_mut() {
+    for (mut velocity, mut controller) in query.iter_mut() {
         let dspeed = controller.target_velocity - velocity.0;
         let accel = controller.acceleration.min(dspeed.length() * 100.0);
-
-        velocity.0 += dspeed.normalize_or_zero() * accel * time.delta_seconds();
+        let cur_vel = velocity.0;
+        velocity.0 += (dspeed.normalize_or_zero() * accel - cur_vel * AIR_RESISTANCE) * time.delta_seconds();
         velocity.0 = velocity.0.clamp_length_max(controller.max_speed);
     }
 }
diff --git a/src/shepherd.rs b/src/shepherd.rs
index 2ed41fb..3f1aa3e 100644
--- a/src/shepherd.rs
+++ b/src/shepherd.rs
@@ -4,8 +4,8 @@ use crate::{player::{DOG_SPEED, DOG_ACCELERATION}, common_storage::CommonStorage
 
 const SHEPHERD_PATH: &str = "test/Knight.png";
 
-const SHEPHERD_SPEED: f32 = DOG_SPEED;
-const SHEPHERD_ACCEL: f32 = DOG_ACCELERATION;
+const SHEPHERD_SPEED: f32 = DOG_SPEED * 0.5;
+const SHEPHERD_ACCEL: f32 = DOG_ACCELERATION * 0.5;
 
 const IGNITE_RADIUS: f32 = 5.0;