From 3ea2f3bc3a43c7cb61386bfdacfe064504ff4fdf Mon Sep 17 00:00:00 2001
From: hut <hut@hut.pm>
Date: Tue, 2 Apr 2024 05:51:50 +0200
Subject: [PATCH] use fastrand for better asteroid distribution

---
 Cargo.lock   |  5 +++--
 Cargo.toml   |  1 +
 src/world.rs | 32 ++++++++++++++++++--------------
 3 files changed, 22 insertions(+), 16 deletions(-)

diff --git a/Cargo.lock b/Cargo.lock
index 4ec62f2..b9adf28 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -1704,9 +1704,9 @@ dependencies = [
 
 [[package]]
 name = "fastrand"
-version = "2.0.1"
+version = "2.0.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "25cbce373ec4653f1a01a31e8a5e5ec0c622dc27ff9c4e6606eefef5cbbed4a5"
+checksum = "658bd65b1cf4c852a3cc96f18a8ce7b5640f6b703f905c7d74532294c2a63984"
 
 [[package]]
 name = "fdeflate"
@@ -2753,6 +2753,7 @@ dependencies = [
  "bevy",
  "bevy_embedded_assets",
  "bevy_xpbd_3d",
+ "fastrand",
  "regex",
 ]
 
diff --git a/Cargo.toml b/Cargo.toml
index 5056c06..d3a7c95 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -14,6 +14,7 @@ regex = "1"
 bevy = { version = "0.13.1", default-features = false, features = ["jpeg", "bevy_asset", "bevy_audio", "bevy_scene", "bevy_winit", "bevy_core_pipeline", "bevy_pbr", "bevy_gltf", "bevy_render", "bevy_text", "bevy_ui", "file_watcher", "multi-threaded", "png", "vorbis", "x11", "tonemapping_luts"]}
 bevy_xpbd_3d = { version = "0.4.2", default-features = false, features = ["3d", "f64", "parry-f64", "parallel", "async-collider"] }
 bevy_embedded_assets = "0.10.2"
+fastrand = "2.0.2"
 
 [features]
 dev = ["bevy/dynamic_linking"]
diff --git a/src/world.rs b/src/world.rs
index e6850c3..b0063cb 100644
--- a/src/world.rs
+++ b/src/world.rs
@@ -6,9 +6,10 @@ use bevy_xpbd_3d::prelude::*;
 use bevy_xpbd_3d::plugins::sync::SyncConfig;
 use std::collections::HashMap;
 use std::f32::consts::PI;
+use fastrand;
 
 const ASTEROID_UPDATE_INTERVAL: f32 = 1.0; // seconds
-const ASTEROID_SIZE_FACTOR: f32 = 5.0;
+const ASTEROID_SIZE_FACTOR: f32 = 3.0;
 const STARS_MAX_MAGNITUDE: f32 = 5.5;
 
 const CENTER_WORLD_ON_PLAYER: bool = true;
@@ -232,6 +233,7 @@ fn spawn_despawn_asteroids(
         }
     }
 
+    let mut rng = fastrand::Rng::new();
     for x in -stepmax..=stepmax {
         for y in -stepmax..=stepmax {
             for z in -stepmax..=stepmax {
@@ -245,9 +247,15 @@ fn spawn_despawn_asteroids(
                     continue;
                 }
 
-                // generate some deterministic pseudorandom numbers seeded with the origin coordinates
-                let rand_s = (4.0*((origin.x+origin.y+origin.z) as f64).sin()
-                            + 3.0*((origin.x+origin.y+origin.z) as f64).cos()).abs() % 1.0;
+                // Get a seed based on all of the origin axes
+                // Probably there's a faster way
+                rng.seed(origin.x as u64);
+                let seed = rng.u64(0..u64::MAX).wrapping_add(origin.y as u64);
+                rng.seed(seed);
+                let seed = rng.u64(0..u64::MAX).wrapping_add(origin.z as u64);
+                rng.seed(seed);
+
+                let rand_s = rng.f32();
                 let size: f32 = (rand_s + 1e-6).powf(-0.5) as f32; // -> between ~1 and 1000
 
                 if rand_s > 0.7 {
@@ -258,18 +266,14 @@ fn spawn_despawn_asteroids(
                     spawned_near += 1;
                 }
 
-                let rand_x = (4.0*((origin.x+origin.y) as f64).sin()
-                            + 3.0*((origin.y+origin.z) as f64).cos()) % 1.0;
-                let rand_y = (4.0*((origin.y+origin.z) as f64).sin()
-                            + 3.0*((origin.z+origin.x) as f64).cos()) % 1.0;
-                let rand_z = (40.0*((origin.z+origin.x) as f64).sin()
-                            + 30.0*((origin.x+origin.y) as f64).cos()) % 1.0;
-                let rand_c = (8.0*((origin.x+origin.z) as f64).sin()
-                            + 4.0*((origin.x+origin.z) as f64).cos()).abs() % 1.0;
-                let class = if rand_c < 0.5 { 0 } else { 1 };
+                let rand_x = rng.f64();
+                let rand_y = rng.f64();
+                let rand_z = rng.f64();
+                let rand_c = rng.bool();
+                let class = if rand_c { 0 } else { 1 };
 
                 //let max_viewdist = ASTEROID_VIEW_RADIUS / ASTEROID_SPAWN_STEP;
-                let wobble = ASTEROID_SPAWN_STEP * 0.3;
+                let wobble = ASTEROID_SPAWN_STEP * 0.5;
                 let pos = DVec3::new(
                     origin.x as f64 * ASTEROID_SPAWN_STEP + wobble * rand_x * 2.0 - 1.0,
                     origin.y as f64 * ASTEROID_SPAWN_STEP + wobble * rand_y * 2.0 - 1.0,