remove randomness

examples/3d/spotlight.rs

@@ -5,7 +5,7 @@ use bevy::{
     pbr::NotShadowCaster,
     prelude::*,
 };
-use rand::{thread_rng, Rng};
+use rand::{rngs::StdRng, Rng, SeedableRng};
 
 fn main() {
     App::new()
@@ -40,10 +40,10 @@ fn setup(
     });
 
     // cubes
-    let mut rng = thread_rng();
-    for _ in 0..100 {
+    let mut rng = StdRng::seed_from_u64(19878367467713);
+    for _ in 0..40 {
         let x = rng.gen_range(-5.0..5.0);
-        let y = rng.gen_range(-5.0..5.0);
+        let y = rng.gen_range(0.0..3.0);
         let z = rng.gen_range(-5.0..5.0);
         commands.spawn((
             PbrBundle {

examples/async_tasks/external_source_external_thread.rs

@@ -3,7 +3,7 @@
 use bevy::prelude::*;
 // Using crossbeam_channel instead of std as std `Receiver` is `!Sync`
 use crossbeam_channel::{bounded, Receiver};
-use rand::Rng;
+use rand::{rngs::StdRng, Rng, SeedableRng};
 use std::time::{Duration, Instant};
 
 fn main() {
@@ -25,17 +25,19 @@ fn setup(mut commands: Commands) {
     commands.spawn(Camera2dBundle::default());
 
     let (tx, rx) = bounded::<u32>(10);
-    std::thread::spawn(move || loop {
-        // Everything here happens in another thread
-        // This is where you could connect to an external data source
-        let mut rng = rand::thread_rng();
-        let start_time = Instant::now();
-        let duration = Duration::from_secs_f32(rng.gen_range(0.0..0.2));
-        while start_time.elapsed() < duration {
-            // Spinning for 'duration', simulating doing hard work!
-        }
+    std::thread::spawn(move || {
+        let mut rng = StdRng::seed_from_u64(19878367467713);
+        loop {
+            // Everything here happens in another thread
+            // This is where you could connect to an external data source
+            let start_time = Instant::now();
+            let duration = Duration::from_secs_f32(rng.gen_range(0.0..0.2));
+            while start_time.elapsed() < duration {
+                // Spinning for 'duration', simulating doing hard work!
+            }
 
-        tx.send(rng.gen_range(0..2000)).unwrap();
+            tx.send(rng.gen_range(0..2000)).unwrap();
+        }
     });
 
     commands.insert_resource(StreamReceiver(rx));
@@ -59,11 +61,7 @@ fn spawn_text(mut commands: Commands, mut reader: EventReader<StreamEvent>) {
         commands.spawn(Text2dBundle {
             text: Text::from_section(event.0.to_string(), text_style.clone())
                 .with_alignment(TextAlignment::Center),
-            transform: Transform::from_xyz(
-                per_frame as f32 * 100.0 + rand::thread_rng().gen_range(-40.0..40.0),
-                300.0,
-                0.0,
-            ),
+            transform: Transform::from_xyz(per_frame as f32 * 100.0, 300.0, 0.0),
             ..default()
         });
     }

examples/ecs/iter_combinations.rs

@@ -1,7 +1,7 @@
 //! Shows how to iterate over combinations of query results.
 
 use bevy::{pbr::AmbientLight, prelude::*};
-use rand::{thread_rng, Rng};
+use rand::{rngs::StdRng, Rng, SeedableRng};
 
 const DELTA_TIME: f32 = 0.01;
 
@@ -56,7 +56,7 @@ fn generate_bodies(
     let color_range = 0.5..1.0;
     let vel_range = -0.5..0.5;
 
-    let mut rng = thread_rng();
+    let mut rng = StdRng::seed_from_u64(19878367467713);
     for _ in 0..NUM_BODIES {
         let radius: f32 = rng.gen_range(0.1..0.7);
         let mass_value = radius.powi(3) * 10.;

examples/ecs/parallel_query.rs

@@ -2,22 +2,23 @@
 
 use bevy::ecs::query::BatchingStrategy;
 use bevy::prelude::*;
-use rand::random;
+use rand::{rngs::StdRng, Rng, SeedableRng};
 
 #[derive(Component, Deref)]
 struct Velocity(Vec2);
 
 fn spawn_system(mut commands: Commands, asset_server: Res<AssetServer>) {
     commands.spawn(Camera2dBundle::default());
     let texture = asset_server.load("branding/icon.png");
+    let mut rng = StdRng::seed_from_u64(19878367467713);
     for _ in 0..128 {
         commands.spawn((
             SpriteBundle {
                 texture: texture.clone(),
                 transform: Transform::from_scale(Vec3::splat(0.1)),
                 ..default()
             },
-            Velocity(20.0 * Vec2::new(random::<f32>() - 0.5, random::<f32>() - 0.5)),
+            Velocity(20.0 * Vec2::new(rng.gen::<f32>() - 0.5, rng.gen::<f32>() - 0.5)),
         ));
     }
 }