Worldgen consts and slices

src/bloxel/storage/bloxel_array.rs

@@ -23,7 +23,7 @@ impl<T: Copy> BloxelArray<T> {
         Self { size, data }
     }
 
-    pub fn from_fn(size: USize3, f: impl Fn(IVec3) -> T) -> Self {
+    pub fn from_fn(size: USize3, mut f: impl FnMut(IVec3) -> T) -> Self {
         let f = |(x, y, z)| f(IVec3::new(x as i32, y as i32, z as i32));
         let data = Array3::from_shape_fn(size, f);
         Self { size, data }

src/bloxel/storage/bloxel_store.rs

@@ -12,7 +12,7 @@ pub trait BloxelStore<T: Copy> {
 pub trait BloxelStoreMut<T: Copy>: BloxelStore<T> {
     fn set(&mut self, pos: IVec3, value: T) -> Result<T, ()>;
 
-    fn update(&mut self, f: impl Fn(IVec3, T) -> T) {
+    fn update(&mut self, mut f: impl FnMut(IVec3, T) -> T) {
         let (w, h, d) = self.size().into();
         for prod in Hom3FCartProd::new(0..w, 0..h, 0..d) {
             let pos = UVec3::from(prod).as_ivec3();

src/bloxel/worldgen/mod.rs

@@ -10,6 +10,10 @@ use crate::{
     TerrainBlocks,
 };
 
+const LOAD_DISTANCE: usize = 12;
+const UNLOAD_DISTANCE: usize = 16;
+const CHUNKS_PER_ITERATION: usize = 12;
+
 pub struct WorldGenPlugin;
 
 impl Plugin for WorldGenPlugin {
@@ -52,13 +56,14 @@ fn create_chunks_around_camera(
         create_chunk(&mut octree, chunk_pos);
     }
 
+    let sqr_load_distance = (LOAD_DISTANCE * LOAD_DISTANCE) as i32;
     let to_create = octree
         .find(|node, exist| {
             (exist != Existing::All).then(|| -node.region().distance_to_squared(chunk_pos))
         })
-        .take_while(|(_, _, neg_sqr_distance)| *neg_sqr_distance > -(12 * 12))
+        .take_while(|(_, _, neg_sqr_distance)| *neg_sqr_distance > -sqr_load_distance)
         .map(|(chunk_pos, _, _)| chunk_pos)
-        .take(12) // Create up to 12 chunks per system iteration.
+        .take(CHUNKS_PER_ITERATION) // Create up to this many chunks per system iteration.
         .collect::<Vec<_>>();
 
     for chunk_pos in to_create {
@@ -82,9 +87,10 @@ fn destroy_chunks_away_from_camera(
         a.max(b)
     };
 
+    let sqr_unload_distance = (UNLOAD_DISTANCE * UNLOAD_DISTANCE) as i32;
     let to_destroy = octree
         .find(|node, exist| (exist != Existing::None).then(|| distance(node)))
-        .take_while(|(_, _, neg_sqr_distance)| *neg_sqr_distance > 16 * 16)
+        .take_while(|(_, _, sqr_distance)| *sqr_distance > sqr_unload_distance)
         .map(|(chunk_pos, _, _)| chunk_pos)
         .collect::<Vec<_>>();
 
@@ -111,6 +117,8 @@ fn generate_terrain(
         return;
     };
 
+    let slices = [terrain.rock, terrain.dirt, terrain.grass, terrain.sand];
+
     for (entity, chunk_pos) in chunks_without_data.iter() {
         let mut data = ChunkData::new(terrain.air);
         data.update(|relative, _| {
@@ -125,7 +133,7 @@ fn generate_terrain(
                 .sample3(float_pos);
 
             if sample > bias {
-                terrain.rock
+                slices[relative.y as usize % slices.len()]
             } else {
                 terrain.air
             }