From c03bf8b622551e2571ba477754d5e8f42b414b7d Mon Sep 17 00:00:00 2001
From: Elias Stepanik <40958815+eliasstepanik@users.noreply.github.com>
Date: Mon, 9 Jun 2025 13:46:48 +0200
Subject: [PATCH] skip empty chunk meshes

---
 .../environment/systems/voxels/meshing.rs     |  8 +++++--
 .../systems/voxels/render_chunks.rs           | 21 +++++++++++++------
 2 files changed, 21 insertions(+), 8 deletions(-)

diff --git a/client/src/plugins/environment/systems/voxels/meshing.rs b/client/src/plugins/environment/systems/voxels/meshing.rs
index bfa853e..c0c3e63 100644
--- a/client/src/plugins/environment/systems/voxels/meshing.rs
+++ b/client/src/plugins/environment/systems/voxels/meshing.rs
@@ -304,7 +304,7 @@ pub(crate) fn mesh_chunk(
     origin: Vec3,
     step:   f32,
     tree:   &SparseVoxelOctree,
-) -> Mesh {
+) -> Option<Mesh> {
     // ────────────────────────────────────────────────────────────────────────────
     // Helpers
     // ────────────────────────────────────────────────────────────────────────────
@@ -462,6 +462,10 @@ pub(crate) fn mesh_chunk(
     // ────────────────────────────────────────────────────────────────────────────
     // Final mesh assembly
     // ────────────────────────────────────────────────────────────────────────────
+    if indices.is_empty() {
+        return None;
+    }
+
     let mut mesh = Mesh::new(PrimitiveTopology::TriangleList, RenderAssetUsages::default());
     mesh.insert_attribute(
         Mesh::ATTRIBUTE_POSITION,
@@ -476,5 +480,5 @@ pub(crate) fn mesh_chunk(
         VertexAttributeValues::Float32x2(uvs),
     );
     mesh.insert_indices(Indices::U32(indices));
-    mesh
+    Some(mesh)
 }
diff --git a/client/src/plugins/environment/systems/voxels/render_chunks.rs b/client/src/plugins/environment/systems/voxels/render_chunks.rs
index a8edc65..36d1eac 100644
--- a/client/src/plugins/environment/systems/voxels/render_chunks.rs
+++ b/client/src/plugins/environment/systems/voxels/render_chunks.rs
@@ -85,13 +85,22 @@ pub fn rebuild_dirty_chunks(
         for (key, buf, origin, step, lod) in bufs {
             if let Some((ent, mesh_h, _mat_h, _)) = existing.get(&key).cloned() {
                 // update mesh in-place; keeps old asset id
-                if let Some(mesh) = meshes.get_mut(&mesh_h) {
-                    *mesh = mesh_chunk(&buf, origin, step, &tree);
+                match mesh_chunk(&buf, origin, step, &tree) {
+                    Some(new_mesh) => {
+                        if let Some(mesh) = meshes.get_mut(&mesh_h) {
+                            *mesh = new_mesh;
+                        }
+                        spawned.0.insert(key, ent);
+                    }
+                    None => {
+                        meshes.remove(&mesh_h);
+                        commands.entity(ent).despawn_recursive();
+                        spawned.0.remove(&key);
+                    }
                 }
-                spawned.0.insert(key, ent);
-            } else {
-                // spawn brand-new chunk
-                let mesh_h = meshes.add(mesh_chunk(&buf, origin, step, &tree));
+            } else if let Some(mesh) = mesh_chunk(&buf, origin, step, &tree) {
+                // spawn brand-new chunk only if mesh has faces
+                let mesh_h = meshes.add(mesh);
                 let mat_h  = materials.add(StandardMaterial::default());
 
                 commands.entity(root.0).with_children(|p| {