From 5d52d3cdf481acc9f9867b8a426a953c8e44abdf Mon Sep 17 00:00:00 2001
From: hut <hut@hut.pm>
Date: Fri, 5 Apr 2024 01:19:46 +0200
Subject: [PATCH] add "wants novelocity" command to icarus

---
 src/actor.rs    | 39 ++++++++++++++++++++++++++++++++++-----
 src/commands.rs | 10 ++++++++++
 src/defs.txt    |  3 ++-
 3 files changed, 46 insertions(+), 6 deletions(-)

diff --git a/src/actor.rs b/src/actor.rs
index 065b00d..3e1cc32 100644
--- a/src/actor.rs
+++ b/src/actor.rs
@@ -13,6 +13,7 @@ impl Plugin for ActorPlugin {
         app.add_systems(FixedUpdate, (
             update_physics_lifeforms,
             handle_wants_norotation,
+            handle_wants_novelocity,
         ));
         app.add_systems(Update, (
             handle_input,
@@ -62,6 +63,7 @@ impl Default for Actor {
 #[derive(Component)] pub struct ActorEnteringVehicle;
 #[derive(Component)] pub struct ActorVehicleBeingEntered;
 #[derive(Component)] pub struct WantsNoRotation;
+#[derive(Component)] pub struct WantsNoVelocity;
 
 #[derive(Component)]
 pub struct LifeForm {
@@ -299,13 +301,14 @@ fn handle_collisions(
 }
 
 fn handle_wants_norotation(
-    time: Res<Time>,
-    mut q_v_ang: Query<(&mut AngularVelocity, &Engine), With<WantsNoRotation>>,
+    //time: Res<Time>,
+    mut q_angularvelocity: Query<(&mut AngularVelocity, &Engine), With<WantsNoRotation>>,
 ) {
-    let d = time.delta_seconds();
-    for (mut v_ang, engine) in &mut q_v_ang {
+    let epsilon = 0.0001;
+    //let d = time.delta_seconds();
+    for (mut v_ang, engine) in &mut q_angularvelocity {
         let total = v_ang.0.length();
-        if total <= 0.0001 {
+        if total <= epsilon {
             if total > 0.0 {
                 v_ang.0 = DVec3::splat(0.0);
             }
@@ -316,3 +319,29 @@ fn handle_wants_norotation(
         }
     }
 }
+
+fn handle_wants_novelocity(
+    time: Res<Time>,
+    mut q_velocity: Query<(&mut LinearVelocity, &Engine), With<WantsNoVelocity>>,
+) {
+    let dt = time.delta_seconds();
+    let epsilon = 0.0001;
+    for (mut v, engine) in &mut q_velocity {
+        let total = v.0.length();
+        if total <= epsilon {
+            if total > 0.0 {
+                v.0 = DVec3::splat(0.0);
+            }
+            // already not moving
+            continue;
+        }
+
+        // TODO: respect engine parameters for different thrusts for different directions
+        let avg_thrust = (engine.thrust_forward + engine.thrust_back + engine.thrust_sideways) / 3.0;
+        let acceleration = (avg_thrust * dt) as f64 * -v.0;
+        v.0 += acceleration;
+        if v.0.length() + epsilon < acceleration.length() {
+            v.0 = DVec3::splat(0.0);
+        }
+    }
+}
diff --git a/src/commands.rs b/src/commands.rs
index 5cd64d8..89e79a7 100644
--- a/src/commands.rs
+++ b/src/commands.rs
@@ -50,6 +50,7 @@ struct ParserState {
     is_vehicle: bool,
     has_physics: bool,
     wants_norotation: bool,
+    wants_novelocity: bool,
     collider_is_mesh: bool,
     thrust_forward: f32,
     thrust_sideways: f32,
@@ -101,6 +102,7 @@ impl Default for ParserState {
             is_vehicle: false,
             has_physics: true,
             wants_norotation: false,
+            wants_novelocity: false,
             collider_is_mesh: false,
             thrust_forward: default_engine.thrust_forward,
             thrust_sideways: default_engine.thrust_forward,
@@ -427,6 +429,9 @@ pub fn load_defs(
             ["wants", "norotation"] => {
                 state.wants_norotation = true;
             }
+            ["wants", "novelocity"] => {
+                state.wants_novelocity = true;
+            }
 
             // Parsing chats
             ["chat", chat_name] => {
@@ -618,8 +623,13 @@ fn spawn_entities(
                 });
             }
             if state.wants_norotation {
+                // NOTE: requires an engine to slow down rotation
                 actor.insert(actor::WantsNoRotation);
             }
+            if state.wants_novelocity {
+                // NOTE: requires an engine to slow down velocity
+                actor.insert(actor::WantsNoVelocity);
+            }
             if let Some(color) = state.light_color {
                 actor.insert(PointLightBundle {
                     point_light: PointLight {
diff --git a/src/defs.txt b/src/defs.txt
index eeab1f0..a2a7b34 100644
--- a/src/defs.txt
+++ b/src/defs.txt
@@ -210,8 +210,9 @@ actor 70 -25 -60 suit
     mass 200.0
     collider capsule 2 1
     angularmomentum 0.1 0.2 0.1
-    thrust 1.2 1 1 3 1.5
+    thrust 1.2 1 1 10 1.5
     wants norotation
+    wants novelocity
     pronoun it
     chat hi_icarus
         name Icarus