From aaab14f0f47669933ada65bcf0f3ca6bf33e03ad Mon Sep 17 00:00:00 2001
From: copygirl <copygirl@mcft.net>
Date: Wed, 26 Mar 2025 19:11:12 +0100
Subject: [PATCH] Add destroy_chunks_away_from_camera system
---
src/bloxel/worldgen/mod.rs | 46 ++++++++++++++++++++++++++++++++++++--
1 file changed, 44 insertions(+), 2 deletions(-)
diff --git a/src/bloxel/worldgen/mod.rs b/src/bloxel/worldgen/mod.rs
index 895beb7..a9a14bf 100644
--- a/src/bloxel/worldgen/mod.rs
+++ b/src/bloxel/worldgen/mod.rs
@@ -14,8 +14,14 @@ pub struct WorldGenPlugin;
impl Plugin for WorldGenPlugin {
fn build(&self, app: &mut App) {
- app.init_resource::<ExistingChunks>()
- .add_systems(Update, (create_chunks_around_camera, generate_terrain));
+ app.init_resource::<ExistingChunks>().add_systems(
+ Update,
+ (
+ create_chunks_around_camera,
+ destroy_chunks_away_from_camera,
+ generate_terrain,
+ ),
+ );
}
}
@@ -60,6 +66,42 @@ fn create_chunks_around_camera(
}
}
+fn destroy_chunks_away_from_camera(
+ mut commands: Commands,
+ mut octree: ResMut<ExistingChunks>,
+ camera: Single<&Transform, With<ControlledCamera>>,
+ chunk_map: Single<&ChunkMap>,
+) {
+ let block_pos = camera.translation.as_ivec3().into();
+ let (chunk_pos, _) = ChunkPos::from_block_pos(block_pos);
+
+ let distance = |node: OctreeNode| -> i32 {
+ let (min, max) = node.region().into();
+ let a = (chunk_pos - min).length_squared();
+ let b = (chunk_pos - max).length_squared();
+ a.max(b)
+ };
+
+ let to_destroy = octree
+ .find(|node, exist| (exist != Existing::None).then(|| distance(node)))
+ .take_while(|(_, _, neg_sqr_distance)| *neg_sqr_distance > 16 * 16)
+ .map(|(chunk_pos, _, _)| chunk_pos)
+ .collect::<Vec<_>>();
+
+ for chunk_pos in to_destroy {
+ let chunk = *chunk_map.get(&chunk_pos).unwrap();
+ commands.entity(chunk).despawn_recursive();
+ octree.update(chunk_pos, |_, children, parent| {
+ let children = children.map(|a| a.as_slice()).unwrap_or_default();
+ *parent = if children.iter().all(|c| *c == Existing::None) {
+ Existing::None
+ } else {
+ Existing::Some
+ }
+ });
+ }
+}
+
fn generate_terrain(
mut commands: Commands,
terrain_blocks: Option<Res<TerrainBlocks>>,