From 9875417232e760f0ca6b2e76a399779745205ca0 Mon Sep 17 00:00:00 2001
From: Felix Ableitner <me@nutomic.com>
Date: Fri, 1 Jan 2021 17:40:58 +0100
Subject: [PATCH] Rewrite and simplify movement, reorder player functions

---
 src/player.rs | 142 +++++++++++++++++++++-----------------------------
 1 file changed, 59 insertions(+), 83 deletions(-)

diff --git a/src/player.rs b/src/player.rs
index 9328384..42534e8 100644
--- a/src/player.rs
+++ b/src/player.rs
@@ -8,17 +8,31 @@ use bevy_rapier3d::{
   },
 };
 
+pub struct PlayerPlugin;
+
+impl Plugin for PlayerPlugin {
+  fn build(&self, app: &mut AppBuilder) {
+    app
+      .init_resource::<State>()
+      .add_system(player_movement_system.system())
+      .add_system(player_look_system.system())
+      .add_startup_system(init_player.system());
+  }
+}
+
+#[derive(Default)]
+struct State {
+  mouse_motion_event_reader: EventReader<MouseMotion>,
+}
+
 struct Player {
   /// The current pitch of the FlyCamera in degrees. This value is always up-to-date, enforced by [FlyCameraPlugin](struct.FlyCameraPlugin.html)
   pitch: f32,
   /// The current pitch of the FlyCamera in degrees. This value is always up-to-date, enforced by [FlyCameraPlugin](struct.FlyCameraPlugin.html)
   yaw: f32,
-  /// The current velocity of the FlyCamera. This value is always up-to-date, enforced by [FlyCameraPlugin](struct.FlyCameraPlugin.html)
-  velocity: Vec3,
 }
 
-const PLAYER_SPEED: f32 = 15.0;
-const PLAYER_FRICTION: f32 = 1.0;
+const PLAYER_SPEED: f32 = 320.0;
 const MOUSE_SENSITIVITY: f32 = 6.0;
 
 impl Player {
@@ -26,11 +40,50 @@ impl Player {
     Self {
       pitch: 0.0,
       yaw: 0.0,
-      velocity: Vec3::zero(),
     }
   }
 }
 
+fn init_player(commands: &mut Commands) {
+  commands
+    .spawn(Camera3dBundle {
+      transform: Transform::from_translation(Vec3::new(0.0, 3.0, 3.0)),
+      ..Default::default()
+    })
+    .with(Player::create())
+    .with(
+      RigidBodyBuilder::new_dynamic()
+        .translation(0.0, 3.0, 0.0)
+        .lock_rotations(),
+    )
+    .with(ColliderBuilder::cylinder(1.0, 0.5).friction(0.0));
+}
+
+fn player_movement_system(
+  time: Res<Time>,
+  mut bodies: ResMut<RigidBodySet>,
+  keyboard_input: Res<Input<KeyCode>>,
+  mut query: Query<(&mut Transform, &RigidBodyHandleComponent), With<Player>>,
+) {
+  for (transform, handle) in query.iter_mut() {
+    let body: &mut RigidBody = bodies.get_mut(handle.handle()).unwrap();
+    let axis_straight = movement_axis(&keyboard_input, KeyCode::D, KeyCode::A);
+    let axis_strafe = movement_axis(&keyboard_input, KeyCode::S, KeyCode::W);
+
+    let rotation = transform.rotation;
+    let mut speed_2d: Vec3 =
+      (strafe_vector(&rotation) * axis_straight) + (forward_vector(&rotation) * axis_strafe);
+    if speed_2d.length() != 0.0 {
+      speed_2d = speed_2d.normalize() * PLAYER_SPEED;
+    }
+
+    let velocity_2d = speed_2d * time.delta_seconds();
+
+    let velocity_3d = Matrix3x1::new(velocity_2d.x, body.linvel().y, velocity_2d.z);
+    body.set_linvel(velocity_3d, true);
+  }
+}
+
 fn forward_vector(rotation: &Quat) -> Vec3 {
   rotation.mul_vec3(Vec3::unit_z()).normalize()
 }
@@ -55,57 +108,7 @@ fn movement_axis(input: &Res<Input<KeyCode>>, plus: KeyCode, minus: KeyCode) ->
   axis
 }
 
-fn camera_movement_system(
-  time: Res<Time>,
-  mut bodies: ResMut<RigidBodySet>,
-  keyboard_input: Res<Input<KeyCode>>,
-  mut query: Query<(&mut Player, &mut Transform, &RigidBodyHandleComponent)>,
-) {
-  for (mut player, transform, handle) in query.iter_mut() {
-    let body: &mut RigidBody = bodies.get_mut(handle.handle()).unwrap();
-    let (axis_h, axis_v, axis_float) = (
-      movement_axis(&keyboard_input, KeyCode::D, KeyCode::A),
-      movement_axis(&keyboard_input, KeyCode::S, KeyCode::W),
-      movement_axis(&keyboard_input, KeyCode::Space, KeyCode::LControl),
-    );
-
-    let rotation = transform.rotation;
-    let accel: Vec3 = (strafe_vector(&rotation) * axis_h)
-      + (forward_vector(&rotation) * axis_v)
-      + (Vec3::unit_y() * axis_float);
-    let accel: Vec3 = if accel.length() != 0.0 {
-      accel.normalize() * PLAYER_SPEED
-    } else {
-      Vec3::zero()
-    };
-
-    let friction: Vec3 = if player.velocity.length() != 0.0 {
-      player.velocity.normalize() * -1.0 * PLAYER_FRICTION
-    } else {
-      Vec3::zero()
-    };
-
-    player.velocity += accel * time.delta_seconds();
-
-    let vel = Matrix3x1::new(player.velocity.x, body.linvel().y, player.velocity.z);
-    body.set_linvel(vel, true);
-
-    let delta_friction = friction * time.delta_seconds();
-
-    player.velocity = if (player.velocity + delta_friction).signum() != player.velocity.signum() {
-      Vec3::zero()
-    } else {
-      player.velocity + delta_friction
-    };
-  }
-}
-
-#[derive(Default)]
-struct State {
-  mouse_motion_event_reader: EventReader<MouseMotion>,
-}
-
-fn mouse_motion_system(
+fn player_look_system(
   time: Res<Time>,
   mut state: ResMut<State>,
   mut bodies: ResMut<RigidBodySet>,
@@ -138,30 +141,3 @@ fn mouse_motion_system(
     body.set_angvel(Matrix3x1::new(pitch_radians, yaw_radians, 0.), true);
   }
 }
-
-pub struct PlayerPlugin;
-
-impl Plugin for PlayerPlugin {
-  fn build(&self, app: &mut AppBuilder) {
-    app
-      .init_resource::<State>()
-      .add_system(camera_movement_system.system())
-      .add_system(mouse_motion_system.system())
-      .add_startup_system(init_player.system());
-  }
-}
-
-fn init_player(commands: &mut Commands) {
-  commands
-    .spawn(Camera3dBundle {
-      transform: Transform::from_translation(Vec3::new(0.0, 3.0, 3.0)),
-      ..Default::default()
-    })
-    .with(Player::create())
-    .with(
-      RigidBodyBuilder::new_dynamic()
-        .translation(0.0, 3.0, 0.0)
-        .lock_rotations(),
-    )
-    .with(ColliderBuilder::cylinder(1.0, 0.5).friction(0.0));
-}