From 9306dff82ea4287924ea80c0d89f13161b0edf06 Mon Sep 17 00:00:00 2001
From: copygirl <copygirl@mcft.net>
Date: Wed, 26 Mar 2025 20:46:41 +0100
Subject: [PATCH] Add simplex based noise generation

---
 Cargo.lock                 |  7 +++++++
 Cargo.toml                 |  1 +
 src/bloxel/worldgen/mod.rs | 20 ++++++++++++--------
 3 files changed, 20 insertions(+), 8 deletions(-)

diff --git a/Cargo.lock b/Cargo.lock
index 0938636..7315946 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -315,6 +315,7 @@ version = "0.1.0"
 dependencies = [
  "bevy",
  "bitvec",
+ "noise-functions",
  "overload",
  "rand 0.9.0",
  "zorder",
@@ -2836,6 +2837,12 @@ dependencies = [
  "libc",
 ]
 
+[[package]]
+name = "noise-functions"
+version = "0.8.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "3420c74fd988a5c7da54fad9b8dba218f15431833817913d252dc59002c199c5"
+
 [[package]]
 name = "nom"
 version = "7.1.3"
diff --git a/Cargo.toml b/Cargo.toml
index f079b61..f6d6f42 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -14,6 +14,7 @@ opt-level = 3
 [dependencies]
 bevy = { version = "0.15.3", features = [ "file_watcher", "embedded_watcher" ] }
 bitvec = "1.0.1"
+noise-functions = "0.8.1"
 overload = "0.1.1"
 rand = "0.9.0"
 zorder = "0.2.2"
diff --git a/src/bloxel/worldgen/mod.rs b/src/bloxel/worldgen/mod.rs
index a9a14bf..15ffccc 100644
--- a/src/bloxel/worldgen/mod.rs
+++ b/src/bloxel/worldgen/mod.rs
@@ -1,5 +1,5 @@
 use bevy::prelude::*;
-use rand::prelude::*;
+use noise_functions::{Noise, Simplex};
 
 use crate::{
     bloxel::{
@@ -111,9 +111,6 @@ fn generate_terrain(
         return;
     };
 
-    let mut rng = rand::rng();
-    let random_blocks = [terrain.grass, terrain.dirt, terrain.rock, terrain.sand];
-
     for (entity, chunk_pos) in chunks_without_data.iter() {
         let mut data = ChunkData::new(terrain.air);
         let size = data.size().as_ivec3();
@@ -122,10 +119,17 @@ fn generate_terrain(
                 for x in 0..size.x {
                     let relative = IVec3::new(x, y, z);
                     let block_pos = chunk_pos.to_block_pos(relative);
-                    let chance = (-block_pos.y as f64 / 32.).clamp(0., 1.);
-                    if rng.random_bool(chance) {
-                        let block = *random_blocks.choose(&mut rng).unwrap();
-                        data.set(relative, block);
+                    let float_pos = Into::<IVec3>::into(block_pos).as_vec3();
+
+                    let bias = ((float_pos.y + 32.) / 64.).clamp(-0.25, 1.);
+                    let sample = Simplex
+                        .fbm(3, 0.65, 2.0)
+                        .weighted(0.4)
+                        .frequency(0.01)
+                        .sample3(float_pos);
+
+                    if sample > bias {
+                        data.set(relative, terrain.rock);
                     }
                 }
             }