Player drag and alignment with gravity

+player jumping

src/plugins/player.rs

@@ -1,9 +1,14 @@
+use std::f32::EPSILON;
+
 use bevy::prelude::*;
 use bevy_rapier3d::prelude::*;
 
-use crate::components::{
-	player::{GravityDirection, PlayerForce, PlayerMotion, PlayerVelocity},
-	tags::Player,
+use crate::{
+	components::{
+		player::{GravityDirection, JumpSpeed, MoveSpeed, PlayerDrag, PlayerForce, PlayerMotion, PlayerVelocity},
+		tags::Player,
+	},
+	utils::rotation::get_alignment_rotation,
 };
 
 pub struct PlayerPlugin;
@@ -11,15 +16,16 @@ pub struct PlayerPlugin;
 impl Plugin for PlayerPlugin {
 	fn build(&self, app: &mut App) {
 		app.add_systems(PreUpdate, keyboard_input.in_set(PlayerInputSystems));
-		app.add_systems(Update, (apply_gravity, apply_forces, apply_motion).chain());
+		app.add_systems(Update, (apply_gravity, apply_forces, apply_motion, apply_drag).chain());
+		app.add_systems(Update, align_with_gravity);
 	}
 }
 
 #[derive(SystemSet, Debug, Clone, PartialEq, Eq, Hash)]
 pub struct PlayerInputSystems;
 
-fn apply_forces(player: Single<(&mut PlayerVelocity, &mut PlayerForce), With<Player>>, time: Res<Time>) {
-	let (mut vel, mut force) = player.into_inner();
+fn apply_forces(player: Single<(&mut PlayerVelocity, &PlayerForce), With<Player>>, time: Res<Time>) {
+	let (mut vel, force) = player.into_inner();
 
 	vel.0 += force.0 * time.delta_secs();
 }
@@ -44,10 +50,18 @@ fn apply_gravity(
 	if !is_grounded {
 		vel.0 += grav * scale.0 * 9.47 * time.delta_secs();
 	} else {
-		vel.0 = vel.0 - vel.0.dot(grav) * grav;
+		let dot = vel.0.dot(grav);
+		if dot > 0.0 {
+			vel.0 = vel.0 - dot * grav;
+		}
 	}
 }
 
+fn apply_drag(player: Single<(&mut PlayerVelocity, &PlayerDrag), With<Player>>, time: Res<Time>) {
+	let (mut vel, drag) = player.into_inner();
+	vel.0 *= (1.0 - drag.0 * time.delta_secs()).max(0.0);
+}
+
 fn apply_motion(
 	player: Single<
 		(
@@ -61,10 +75,9 @@ fn apply_motion(
 	time: Res<Time>,
 ) {
 	let (mut controller, transform, vel, motion) = player.into_inner();
-	let max_vel = vel.0.clamp_length_max(500.0);
+	// let max_vel = vel.0.clamp_length_max(500.0);
 	let global_motion = transform.rotation * motion.0;
-	controller.translation =
-		Some((max_vel + global_motion) * controller.custom_mass.unwrap_or(1.0) * time.delta_secs());
+	controller.translation = Some((vel.0 + global_motion) * controller.custom_mass.unwrap_or(1.0) * time.delta_secs());
 }
 
 fn keyboard_input(
@@ -73,13 +86,15 @@ fn keyboard_input(
 		(
 			&mut PlayerMotion,
 			&mut PlayerVelocity,
+			&MoveSpeed,
+			&JumpSpeed,
 			&Transform,
 			Option<&KinematicCharacterControllerOutput>,
 		),
 		With<Player>,
 	>,
 ) {
-	let (mut motion, mut vel, transform, output) = player.into_inner();
+	let (mut motion, mut vel, speed, jump, transform, output) = player.into_inner();
 	let mut move_vec = Vec3::ZERO;
 
 	if key.pressed(KeyCode::KeyW) {
@@ -94,18 +109,13 @@ fn keyboard_input(
 		move_vec.x = 1.0;
 	}
 
+	move_vec = move_vec.normalize_or_zero() * speed.0;
+
 	let is_grounded = output.map(|o| o.grounded).unwrap_or(false);
 	if key.just_pressed(KeyCode::Space) && is_grounded {
-		vel.0 += transform.up() * 200.0;
+		vel.0 += transform.up() * jump.0;
 	}
 
-	let angle = if key.pressed(KeyCode::KeyQ) {
-		-0.1
-	} else if key.pressed(KeyCode::KeyE) {
-		0.1
-	} else {
-		0.0
-	};
 	motion.0 = move_vec;
 
 	// transform.rotate_z(angle * time.delta_secs());
@@ -113,3 +123,32 @@ fn keyboard_input(
 	// move_vec += transform.down().as_vec3();
 	// controller.translation = Some(move_vec * time.delta_secs());
 }
+
+fn align_with_gravity(
+	player: Single<
+		(
+			&mut Transform,
+			&GravityDirection,
+			Option<&KinematicCharacterControllerOutput>,
+		),
+		With<Player>,
+	>,
+	time: Res<Time>,
+) {
+	let (mut transform, grav, output) = player.into_inner();
+	let is_grounded = output.map(|o| o.grounded).unwrap_or(false);
+
+	if !is_grounded {
+		return;
+	}
+
+	let Some(grav_dir) = grav.0 else {
+		return;
+	};
+
+	let cur_up = transform.up();
+	let grav_up = grav_dir * -1.0;
+
+	let desired_rotation = get_alignment_rotation(cur_up, grav_up);
+	transform.rotation = transform.rotation.lerp(desired_rotation, time.delta_secs());
+}