Merge pull request #26 from eliasstepanik/codex/build-texture-atlas-for-voxel-world

Add texture atlas for voxels

client/src/plugins/environment/environment_plugin.rs

@@ -9,6 +9,7 @@ use crate::plugins::environment::systems::voxels::queue_systems::{
     enqueue_visible_chunks, process_chunk_queue,
 };
 use crate::plugins::environment::systems::voxels::render_chunks::rebuild_dirty_chunks;
+use crate::plugins::environment::systems::voxels::atlas::{VoxelTextureAtlas};
 use crate::plugins::environment::systems::voxels::structure::{
     ChunkBudget, ChunkCullingCfg, ChunkQueue, MeshBufferPool, PrevCameraChunk, SparseVoxelOctree,
     SpawnedChunks,
@@ -22,6 +23,7 @@ impl Plugin for EnvironmentPlugin {
         app.add_systems(
             Startup,
             (
+                setup_texture_atlas,
                 crate::plugins::environment::systems::camera_system::setup,
                 crate::plugins::environment::systems::environment_system::setup
                     .after(crate::plugins::environment::systems::camera_system::setup),
@@ -89,3 +91,8 @@ fn should_draw_grid(octree_query: Query<&SparseVoxelOctree>) -> bool {
     };
     octree.show_world_grid
 }
+
+fn setup_texture_atlas(mut commands: Commands, mut images: ResMut<Assets<Image>>) {
+    let atlas = VoxelTextureAtlas::generate(&mut images);
+    commands.insert_resource(atlas);
+}

client/src/plugins/environment/systems/voxel_system.rs

@@ -1,25 +1,21 @@
-use std::path::Path;
-use rayon::prelude::*;
 use crate::plugins::big_space::big_space_plugin::RootGrid;
 use crate::plugins::environment::systems::voxels::structure::*;
+use rayon::prelude::*;
+use std::path::Path;
 
 use bevy::prelude::*;
 use bevy::render::mesh::*;
 use noise::{NoiseFn, Perlin};
-use rand::{thread_rng, Rng};
+use rand::{Rng, thread_rng};
 
-pub fn setup(
-    mut commands: Commands,
-    root: Res<RootGrid>,
-) {
+pub fn setup(mut commands: Commands, root: Res<RootGrid>) {
     // Octree parameters
-    let unit_size        = 1.0_f32;
+    let unit_size = 1.0_f32;
     let octree_base_size = 64.0 * unit_size;
-    let octree_depth     = 10;
+    let octree_depth = 10;
 
     let path = Path::new("octree.bin");
 
-
     let mut octree = if path.exists() {
         match SparseVoxelOctree::load_from_file(path) {
             Ok(tree) => tree,
@@ -30,7 +26,6 @@ pub fn setup(
         }
     } else {
         let mut tree = SparseVoxelOctree::new(octree_depth, octree_base_size, false, false, false);
-        let color = Color::srgb(0.2, 0.8, 0.2);
         // How many random spheres?
         /*const NUM_SPHERES: usize = 5;
         let mut rng = threald_rng();
@@ -44,30 +39,22 @@ pub fn setup(
 
             let radius = rng.gen_range(20..=150);     // voxels
 
-            generate_voxel_sphere_parallel(&mut tree, center, radius, color);
+            generate_voxel_sphere_parallel(&mut tree, center, radius);
         }*/
-        
-        generate_voxel_sphere(&mut tree, 200, color);
+
+        generate_voxel_sphere(&mut tree, 200);
         tree
     };
 
-
-
-
     // Attach octree to the scene graph
     commands.entity(root.0).with_children(|parent| {
         parent.spawn((Transform::default(), octree));
     });
 }
 
-pub fn generate_voxel_sphere_parallel(
-    octree: &mut SparseVoxelOctree,
-    center: Vec3,
-    radius: i32,
-    color: Color,
-) {
-    let step       = octree.get_spacing_at_depth(octree.max_depth);
-    let radius_sq  = radius * radius;
+pub fn generate_voxel_sphere_parallel(octree: &mut SparseVoxelOctree, center: Vec3, radius: i32) {
+    let step = octree.get_spacing_at_depth(octree.max_depth);
+    let radius_sq = radius * radius;
 
     // 1. Collect voxel positions in parallel
     let voxels: Vec<(Vec3, Voxel)> = (-radius..=radius)
@@ -75,7 +62,7 @@ pub fn generate_voxel_sphere_parallel(
         .flat_map_iter(|ix| {
             let dx2 = ix * ix;
             (-radius..=radius).flat_map(move |iy| {
-                let dy2   = iy * iy;
+                let dy2 = iy * iy;
                 let r2_xy = dx2 + dy2;
 
                 if r2_xy > radius_sq {
@@ -83,14 +70,16 @@ pub fn generate_voxel_sphere_parallel(
                 }
 
                 let max_z = ((radius_sq - r2_xy) as f32).sqrt() as i32;
-                (-max_z..=max_z).map(move |iz| {
-                    let pos = Vec3::new(
-                        center.x + ix as f32 * step,
-                        center.y + iy as f32 * step,
-                        center.z + iz as f32 * step,
-                    );
-                    (pos, Voxel { color })
-                }).collect::<Vec<_>>()
+                (-max_z..=max_z)
+                    .map(move |iz| {
+                        let pos = Vec3::new(
+                            center.x + ix as f32 * step,
+                            center.y + iy as f32 * step,
+                            center.z + iz as f32 * step,
+                        );
+                        (pos, Voxel::random_sides())
+                    })
+                    .collect::<Vec<_>>()
             })
         })
         .collect();
@@ -101,12 +90,7 @@ pub fn generate_voxel_sphere_parallel(
     }
 }
 
-
-fn generate_voxel_sphere(
-    octree: &mut SparseVoxelOctree,
-    planet_radius: i32,
-    voxel_color: Color,
-) {
+fn generate_voxel_sphere(octree: &mut SparseVoxelOctree, planet_radius: i32) {
     // For simplicity, we center the sphere around (0,0,0).
     // We'll loop over a cubic region [-planet_radius, +planet_radius] in x, y, z
     let min = -planet_radius;
@@ -131,9 +115,7 @@ fn generate_voxel_sphere(
                     let position = Vec3::new(wx, wy, wz);
 
                     // Insert the voxel
-                    let voxel = Voxel {
-                        color: voxel_color,
-                    };
+                    let voxel = Voxel::random_sides();
                     octree.insert(position, voxel);
                 }
             }
@@ -141,13 +123,9 @@ fn generate_voxel_sphere(
     }
 }
 
-
 /// Inserts a 16x256x16 "column" of voxels into the octree at (0,0,0) corner.
 /// If you want it offset or centered differently, just adjust the for-loop ranges or offsets.
-fn generate_voxel_rect(
-    octree: &mut SparseVoxelOctree,
-    voxel_color: Color,
-) {
+fn generate_voxel_rect(octree: &mut SparseVoxelOctree) {
     // The dimensions of our rectangle: 16 x 256 x 16
     let size_x = 16;
     let size_y = 256;
@@ -172,21 +150,14 @@ fn generate_voxel_rect(
                 let position = Vec3::new(wx, wy, wz);
 
                 // Insert the voxel
-                let voxel = Voxel {
-                    color: voxel_color,
-                };
+                let voxel = Voxel::random_sides();
                 octree.insert(position, voxel);
             }
         }
     }
 }
 
-fn generate_large_plane(
-    octree: &mut SparseVoxelOctree,
-    width: usize,
-    depth: usize,
-    color: Color,
-) {
+fn generate_large_plane(octree: &mut SparseVoxelOctree, width: usize, depth: usize) {
     // We'll get the voxel spacing (size at the deepest level).
     let step = octree.get_spacing_at_depth(octree.max_depth);
 
@@ -207,20 +178,16 @@ fn generate_large_plane(
             let position = Vec3::new(wx, wy, wz);
 
             // Insert the voxel
-            let voxel = Voxel {
-                color,
-            };
+            let voxel = Voxel::random_sides();
             octree.insert(position, voxel);
         }
     }
 }
 
-
 pub fn generate_solid_plane_with_noise(
     octree: &mut SparseVoxelOctree,
     width: usize,
     depth: usize,
-    color: Color,
     noise: &Perlin,
     frequency: f32,
     amplitude: f32,
@@ -245,13 +212,9 @@ pub fn generate_solid_plane_with_noise(
 
             // Fill from layer 0 up to max_layer
             for iy in 0..=max_layer {
-                let position = Vec3::new(
-                    x * step,
-                    iy as f32 * step,
-                    z * step,
-                );
+                let position = Vec3::new(x * step, iy as f32 * step, z * step);
 
-                let voxel = Voxel { color };
+                let voxel = Voxel::random_sides();
                 octree.insert(position, voxel);
             }
         }

client/src/plugins/environment/systems/voxels/atlas.rs

@@ -0,0 +1,71 @@
+use bevy::asset::RenderAssetUsages;
+use bevy::prelude::*;
+use bevy::render::render_resource::{Extent3d, TextureDimension, TextureFormat};
+
+/// Configuration and handle for the voxel texture atlas.
+#[derive(Resource, Clone)]
+pub struct VoxelTextureAtlas {
+    pub handle: Handle<Image>,
+    pub columns: usize,
+    pub rows: usize,
+}
+
+impl VoxelTextureAtlas {
+    /// Create a simple procedural atlas with solid colors.
+    pub fn generate(images: &mut Assets<Image>) -> Self {
+        let tile_size = 16u32;
+        let columns = 2;
+        let rows = 3;
+        let width = tile_size * columns as u32;
+        let height = tile_size * rows as u32;
+        let mut data = vec![0u8; (width * height * 4) as usize];
+        let colors = [
+            [255, 0, 0, 255],   // 0: red
+            [0, 0, 0, 255],     // 1: black
+            [0, 255, 0, 255],   // 2: green
+            [0, 0, 255, 255],   // 3: blue
+            [255, 255, 0, 255], // 4: yellow
+            [255, 0, 255, 255], // 5: magenta
+        ];
+        for (i, col) in colors.iter().enumerate() {
+            let cx = (i % columns) as u32 * tile_size;
+            let cy = (i / columns) as u32 * tile_size;
+            for y in 0..tile_size {
+                for x in 0..tile_size {
+                    let idx = (((cy + y) * width + (cx + x)) * 4) as usize;
+                    data[idx..idx + 4].copy_from_slice(col);
+                }
+            }
+        }
+        let image = Image::new_fill(
+            Extent3d {
+                width,
+                height,
+                depth_or_array_layers: 1,
+            },
+            TextureDimension::D2,
+            &data,
+            TextureFormat::Rgba8UnormSrgb,
+            RenderAssetUsages::default(),
+        );
+        let handle = images.add(image);
+        Self {
+            handle,
+            columns,
+            rows,
+        }
+    }
+
+    /// Compute UV coordinates for the given atlas index.
+    pub fn uv_rect(&self, index: usize) -> [[f32; 2]; 4] {
+        let col = index % self.columns;
+        let row = index / self.columns;
+        let cols = self.columns as f32;
+        let rows = self.rows as f32;
+        let u0 = col as f32 / cols;
+        let v0 = row as f32 / rows;
+        let u1 = (col + 1) as f32 / cols;
+        let v1 = (row + 1) as f32 / rows;
+        [[u0, v1], [u1, v1], [u1, v0], [u0, v0]]
+    }
+}

client/src/plugins/environment/systems/voxels/debug.rs

@@ -1,5 +1,5 @@
-use bevy::prelude::*;
 use crate::plugins::environment::systems::voxels::structure::*;
+use bevy::prelude::*;
 
 /// Visualize each node of the octree as a scaled cuboid, **center-based**.
 /// `octree_tf.translation` is the world-space center of the root bounding box.
@@ -13,8 +13,7 @@ pub fn visualize_octree_system(
 
         // Draw a translucent cuboid for the root
         gizmos.cuboid(
-            Transform::from_translation(octree_tf.translation)
-                .with_scale(Vec3::splat(octree.size)),
+            Transform::from_translation(octree_tf.translation).with_scale(Vec3::splat(octree.size)),
             Color::srgba(1.0, 1.0, 0.0, 0.15),
         );
 
@@ -85,9 +84,8 @@ fn visualize_recursive_center(
 
                 // Draw a small cuboid at the same center as the parent node.
                 gizmos.cuboid(
-                    Transform::from_translation(parent_center)
-                        .with_scale(Vec3::splat(leaf_size)),
-                    voxel.color,
+                    Transform::from_translation(parent_center).with_scale(Vec3::splat(leaf_size)),
+                    Color::WHITE,
                 );
             }
         }
@@ -100,7 +98,9 @@ pub fn draw_grid(
     camera_query: Query<&Transform, With<Camera>>,
     octree_query: Query<(&SparseVoxelOctree, &Transform)>,
 ) {
-    let Ok(camera_tf) = camera_query.get_single() else { return };
+    let Ok(camera_tf) = camera_query.get_single() else {
+        return;
+    };
     let camera_pos = camera_tf.translation;
 
     for (octree, octree_tf) in octree_query.iter() {
@@ -142,4 +142,4 @@ pub fn draw_grid(
             gizmos.line(p3, p4, Color::WHITE);
         }
     }
-}
+}

client/src/plugins/environment/systems/voxels/meshing.rs

@@ -1,4 +1,5 @@
 use crate::plugins::environment::systems::voxels::structure::*;
+use crate::plugins::environment::systems::voxels::atlas::VoxelTextureAtlas;
 use bevy::asset::RenderAssetUsages;
 use bevy::prelude::*;
 use bevy::render::mesh::{Indices, Mesh, PrimitiveTopology, VertexAttributeValues};
@@ -304,6 +305,7 @@ pub(crate) fn mesh_chunk(
     step: f32,
     tree: &SparseVoxelOctree,
     pool: &mut MeshBufferPool,
+    atlas: &VoxelTextureAtlas,
 ) -> Option<Mesh> {
     // ────────────────────────────────────────────────────────────────────────────
     // Helpers
@@ -313,15 +315,15 @@ pub(crate) fn mesh_chunk(
     const MASK_LEN: usize = N * N;
 
     // Safe voxel query that falls back to the octree for out‑of‑chunk requests.
-    let filled = |x: i32, y: i32, z: i32| -> bool {
+    let get_voxel = |x: i32, y: i32, z: i32| -> Option<Voxel> {
         if (0..CHUNK_SIZE).contains(&x)
             && (0..CHUNK_SIZE).contains(&y)
             && (0..CHUNK_SIZE).contains(&z)
         {
-            buffer[x as usize][y as usize][z as usize].is_some()
+            buffer[x as usize][y as usize][z as usize]
         } else {
             let world = origin + Vec3::new(x as f32 * step, y as f32 * step, z as f32 * step);
-            tree.get_voxel_at_world_coords(world).is_some()
+            tree.get_voxel_at_world_coords(world).copied()
         }
     };
 
@@ -341,7 +343,7 @@ pub(crate) fn mesh_chunk(
     let uvs = &mut pool.uvs;
     let indices = &mut pool.indices;
 
-    let mut push_quad = |base: Vec3, size: Vec2, n: Vec3, u: Vec3, v: Vec3| {
+    let mut push_quad = |base: Vec3, size: Vec2, n: Vec3, u: Vec3, v: Vec3, tex_id: usize| {
         let i0 = positions.len() as u32;
         positions.extend_from_slice(&[
             (base).into(),
@@ -350,7 +352,8 @@ pub(crate) fn mesh_chunk(
             (base + v * size.y).into(),
         ]);
         normals.extend_from_slice(&[[n.x, n.y, n.z]; 4]);
-        uvs.extend_from_slice(&[[0.0, 1.0], [1.0, 1.0], [1.0, 0.0], [0.0, 0.0]]);
+        let uv_rect = atlas.uv_rect(tex_id);
+        uvs.extend_from_slice(&uv_rect);
 
         if n.x + n.y + n.z >= 0.0 {
             indices.extend_from_slice(&[i0, i0 + 1, i0 + 2, i0 + 2, i0 + 3, i0]);
@@ -382,7 +385,7 @@ pub(crate) fn mesh_chunk(
         for slice in 0..=N {
             // Build the face mask for this slice using a fixed-size array to
             // avoid heap allocations.
-            let mut mask = [false; MASK_LEN];
+            let mut mask = [None::<usize>; MASK_LEN];
             let mut visited = [false; MASK_LEN];
             let idx = |u: usize, v: usize| -> usize { u * N + v };
 
@@ -400,10 +403,19 @@ pub(crate) fn mesh_chunk(
                     neighbor[u_axis] = u as i32;
                     neighbor[v_axis] = v as i32;
 
-                    if filled(cell[0], cell[1], cell[2])
-                        && !filled(neighbor[0], neighbor[1], neighbor[2])
-                    {
-                        mask[idx(u, v)] = true;
+                    if let Some(vox) = get_voxel(cell[0], cell[1], cell[2]) {
+                        if get_voxel(neighbor[0], neighbor[1], neighbor[2]).is_none() {
+                            let face_idx = match (axis, dir) {
+                                (0, -1) => 0,
+                                (0, 1) => 1,
+                                (1, -1) => 2,
+                                (1, 1) => 3,
+                                (2, -1) => 4,
+                                (2, 1) => 5,
+                                _ => unreachable!(),
+                            };
+                            mask[idx(u, v)] = Some(vox.textures[face_idx]);
+                        }
                     }
                 }
             }
@@ -411,14 +423,15 @@ pub(crate) fn mesh_chunk(
             // Greedy merge the mask into maximal rectangles.
             for u0 in 0..N {
                 for v0 in 0..N {
-                    if !mask[idx(u0, v0)] || visited[idx(u0, v0)] {
+                    if visited[idx(u0, v0)] {
                         continue;
                     }
+                    let Some(tex_id) = mask[idx(u0, v0)] else { continue };
 
                     // Determine the rectangle width.
                     let mut width = 1;
                     while u0 + width < N
-                        && mask[idx(u0 + width, v0)]
+                        && mask[idx(u0 + width, v0)] == Some(tex_id)
                         && !visited[idx(u0 + width, v0)]
                     {
                         width += 1;
@@ -428,7 +441,7 @@ pub(crate) fn mesh_chunk(
                     let mut height = 1;
                     'h: while v0 + height < N {
                         for du in 0..width {
-                            if !mask[idx(u0 + du, v0 + height)]
+                            if mask[idx(u0 + du, v0 + height)] != Some(tex_id)
                                 || visited[idx(u0 + du, v0 + height)]
                             {
                                 break 'h;
@@ -466,7 +479,7 @@ pub(crate) fn mesh_chunk(
                     }
 
                     let size = Vec2::new(width as f32 * step, height as f32 * step);
-                    push_quad(base, size, face_normal, u_vec, v_vec);
+                    push_quad(base, size, face_normal, u_vec, v_vec, tex_id);
                 }
             }
         }

client/src/plugins/environment/systems/voxels/mod.rs

@@ -10,3 +10,4 @@ mod meshing;
 pub mod meshing_gpu;
 pub mod queue_systems;
 pub mod render_chunks;
+pub mod atlas;

client/src/plugins/environment/systems/voxels/octree.rs

@@ -1,19 +1,27 @@
-use std::collections::{HashMap, HashSet};
-use std::path::Path;
-use std::io;
-use bincode;
+use crate::plugins::environment::systems::voxels::helper::chunk_key_from_world;
+use crate::plugins::environment::systems::voxels::structure::{
+    AABB, CHUNK_SIZE, ChunkKey, DirtyVoxel, NEIGHBOR_OFFSETS, OctreeNode, Ray, SparseVoxelOctree,
+    Voxel,
+};
 use bevy::asset::Assets;
-use bevy::color::Color;
 use bevy::math::{DQuat, DVec3};
 use bevy::prelude::*;
 use bevy::render::mesh::{Indices, PrimitiveTopology, VertexAttributeValues};
 use bevy::render::render_asset::RenderAssetUsages;
-use crate::plugins::environment::systems::voxels::helper::chunk_key_from_world;
-use crate::plugins::environment::systems::voxels::structure::{DirtyVoxel, OctreeNode, Ray, SparseVoxelOctree, Voxel, AABB, NEIGHBOR_OFFSETS, CHUNK_SIZE, ChunkKey};
+use bincode;
+use std::collections::{HashMap, HashSet};
+use std::io;
+use std::path::Path;
 
 impl SparseVoxelOctree {
     /// Creates a new octree with the specified max depth, size, and wireframe visibility.
-    pub fn new(max_depth: u32, size: f32, show_wireframe: bool, show_world_grid: bool, show_chunks: bool) -> Self {
+    pub fn new(
+        max_depth: u32,
+        size: f32,
+        show_wireframe: bool,
+        show_world_grid: bool,
+        show_chunks: bool,
+    ) -> Self {
         Self {
             root: OctreeNode::new(),
             max_depth,
@@ -38,9 +46,7 @@ impl SparseVoxelOctree {
             world_center = self.denormalize_voxel_center(aligned);
         }
 
-        let dirty_voxel = DirtyVoxel{
-            position: aligned,
-        };
+        let dirty_voxel = DirtyVoxel { position: aligned };
 
         self.dirty.push(dirty_voxel);
         let key = chunk_key_from_world(self, position);
@@ -48,7 +54,6 @@ impl SparseVoxelOctree {
         self.mark_neighbor_chunks_dirty(position);
         self.occupied_chunks.insert(key);
 
-
         Self::insert_recursive(&mut self.root, aligned, voxel, self.max_depth);
     }
 
@@ -147,9 +152,12 @@ impl SparseVoxelOctree {
     /// Mark all six neighbor chunks of the given key as dirty if they exist.
     pub fn mark_neighbors_dirty_from_key(&mut self, key: ChunkKey) {
         let offsets = [
-            (-1, 0, 0), (1, 0, 0),
-            (0, -1, 0), (0, 1, 0),
-            (0, 0, -1), (0, 0, 1),
+            (-1, 0, 0),
+            (1, 0, 0),
+            (0, -1, 0),
+            (0, 1, 0),
+            (0, 0, -1),
+            (0, 0, 1),
         ];
         for (dx, dy, dz) in offsets {
             let neighbor = ChunkKey(key.0 + dx, key.1 + dy, key.2 + dz);
@@ -159,13 +167,7 @@ impl SparseVoxelOctree {
         }
     }
 
-    fn remove_recursive(
-        node: &mut OctreeNode,
-        x: f32,
-        y: f32,
-        z: f32,
-        depth: u32,
-    ) -> bool {
+    fn remove_recursive(node: &mut OctreeNode, x: f32, y: f32, z: f32, depth: u32) -> bool {
         if depth == 0 {
             if node.voxel.is_some() {
                 node.voxel = None;
@@ -222,7 +224,6 @@ impl SparseVoxelOctree {
         false
     }
 
-
     fn expand_root(&mut self, _x: f32, _y: f32, _z: f32) {
         info!("Root expanding ...");
         // Save the old root and its size.
@@ -244,7 +245,15 @@ impl SparseVoxelOctree {
     /// The coordinate system here assumes the node covers [–old_size/2, +old_size/2] in each axis.
     fn collect_voxels_from_node(node: &OctreeNode, old_size: f32) -> Vec<(Vec3, Voxel, u32)> {
         let mut voxels = Vec::new();
-        Self::collect_voxels_recursive(node, -old_size / 2.0, -old_size / 2.0, -old_size / 2.0, old_size, 0, &mut voxels);
+        Self::collect_voxels_recursive(
+            node,
+            -old_size / 2.0,
+            -old_size / 2.0,
+            -old_size / 2.0,
+            old_size,
+            0,
+            &mut voxels,
+        );
         voxels
     }
 
@@ -270,14 +279,20 @@ impl SparseVoxelOctree {
                 let offset_x = if (i & 1) != 0 { half } else { 0.0 };
                 let offset_y = if (i & 2) != 0 { half } else { 0.0 };
                 let offset_z = if (i & 4) != 0 { half } else { 0.0 };
-                Self::collect_voxels_recursive(child, x + offset_x, y + offset_y, z + offset_z, half, depth + 1, out);
+                Self::collect_voxels_recursive(
+                    child,
+                    x + offset_x,
+                    y + offset_y,
+                    z + offset_z,
+                    half,
+                    depth + 1,
+                    out,
+                );
             }
         }
     }
 
-
-
-    pub fn traverse(&self) -> Vec<(Vec3, Color, u32)> {
+    pub fn traverse(&self) -> Vec<(Vec3, u32)> {
         let mut voxels = Vec::new();
         // Start at the normalized center (0.5, 0.5, 0.5) rather than (0,0,0)
         Self::traverse_recursive(
@@ -296,20 +311,20 @@ impl SparseVoxelOctree {
         local_center: Vec3,
         size: f32,
         depth: u32,
-        out: &mut Vec<(Vec3, Color, u32)>,
+        out: &mut Vec<(Vec3, u32)>,
         octree: &SparseVoxelOctree,
     ) {
         // If a leaf contains a voxel, record its world-space center
         if node.is_leaf {
             if let Some(voxel) = node.voxel {
-                out.push((octree.denormalize_voxel_center(local_center), voxel.color, depth));
+                out.push((octree.denormalize_voxel_center(local_center), depth));
             }
         }
 
         // If the node has children, subdivide the cell into 8 subcells.
         if let Some(ref children) = node.children {
-            let offset = size / 4.0;  // child center offset from parent center
-            let new_size = size / 2.0;  // each child cell's size in normalized space
+            let offset = size / 4.0; // child center offset from parent center
+            let new_size = size / 2.0; // each child cell's size in normalized space
             for (i, child) in children.iter().enumerate() {
                 // Compute each axis' offset: use +offset if the bit is set, else -offset.
                 let dx = if (i & 1) != 0 { offset } else { -offset };
@@ -322,8 +337,6 @@ impl SparseVoxelOctree {
         }
     }
 
-
-
     /// Retrieve a voxel from the octree if it exists (x,y,z in [-0.5..+0.5] range).
     pub fn get_voxel_at(&self, x: f32, y: f32, z: f32) -> Option<&Voxel> {
         Self::get_voxel_recursive(&self.root, x, y, z)
@@ -388,7 +401,6 @@ impl SparseVoxelOctree {
         self.get_voxel_at_world_coords(neighbor_world).is_some()
     }
 
-
     /// Performs a raycast against the octree and returns the first intersected voxel.
     pub fn raycast(&self, ray: &Ray) -> Option<(f32, f32, f32, u32, Vec3)> {
         // Start from the root node
@@ -397,12 +409,7 @@ impl SparseVoxelOctree {
             min: Vec3::new(-half_size as f32, -half_size as f32, -half_size as f32),
             max: Vec3::new(half_size as f32, half_size as f32, half_size as f32),
         };
-        self.raycast_recursive(
-            &self.root,
-            ray,
-            &root_bounds,
-            0,
-        )
+        self.raycast_recursive(&self.root, ray, &root_bounds, 0)
     }
 
     fn raycast_recursive(
@@ -435,7 +442,8 @@ impl SparseVoxelOctree {
                 let mut hits = Vec::new();
                 for (i, child) in children.iter().enumerate() {
                     let child_bounds = self.compute_child_bounds(bounds, i);
-                    if let Some(hit) = self.raycast_recursive(child, ray, &child_bounds, depth + 1) {
+                    if let Some(hit) = self.raycast_recursive(child, ray, &child_bounds, depth + 1)
+                    {
                         hits.push(hit);
                     }
                 }
@@ -445,11 +453,11 @@ impl SparseVoxelOctree {
                         let dist_a = ((a.0 as f32 - ray.origin.x).powi(2)
                             + (a.1 as f32 - ray.origin.y).powi(2)
                             + (a.2 as f32 - ray.origin.z).powi(2))
-                            .sqrt();
+                        .sqrt();
                         let dist_b = ((b.0 as f32 - ray.origin.x).powi(2)
                             + (b.1 as f32 - ray.origin.y).powi(2)
                             + (b.2 as f32 - ray.origin.z).powi(2))
-                            .sqrt();
+                        .sqrt();
                         dist_a.partial_cmp(&dist_b).unwrap()
                     });
                     return Some(hits[0]);
@@ -462,16 +470,15 @@ impl SparseVoxelOctree {
 
     /// Save the octree to a file using bincode serialization.
     pub fn save_to_file<P: AsRef<Path>>(&self, path: P) -> io::Result<()> {
-        let data = bincode::serialize(self)
-            .map_err(|e| io::Error::new(io::ErrorKind::Other, e))?;
+        let data = bincode::serialize(self).map_err(|e| io::Error::new(io::ErrorKind::Other, e))?;
         std::fs::write(path, data)
     }
 
     /// Load an octree from a file and rebuild runtime caches.
     pub fn load_from_file<P: AsRef<Path>>(path: P) -> io::Result<Self> {
         let bytes = std::fs::read(path)?;
-        let mut tree: Self = bincode::deserialize(&bytes)
-            .map_err(|e| io::Error::new(io::ErrorKind::Other, e))?;
+        let mut tree: Self =
+            bincode::deserialize(&bytes).map_err(|e| io::Error::new(io::ErrorKind::Other, e))?;
         tree.rebuild_cache();
         Ok(tree)
     }
@@ -481,7 +488,7 @@ impl SparseVoxelOctree {
         self.dirty.clear();
         self.dirty_chunks.clear();
         self.occupied_chunks.clear();
-        
+
         let voxels = Self::collect_voxels_from_node(&self.root, self.size);
         for (pos, _voxel, _depth) in voxels {
             let key = chunk_key_from_world(self, pos);
@@ -489,4 +496,3 @@ impl SparseVoxelOctree {
         }
     }
 }
-

client/src/plugins/environment/systems/voxels/render_chunks.rs

@@ -1,6 +1,7 @@
 use crate::plugins::big_space::big_space_plugin::RootGrid;
 use crate::plugins::environment::systems::voxels::meshing::mesh_chunk;
 use crate::plugins::environment::systems::voxels::structure::*;
+use crate::plugins::environment::systems::voxels::atlas::VoxelTextureAtlas;
 use bevy::pbr::wireframe::Wireframe;
 use bevy::prelude::*;
 use bevy::render::mesh::Mesh;
@@ -25,6 +26,7 @@ pub fn rebuild_dirty_chunks(
     mut spawned: ResMut<SpawnedChunks>,
     mut pool: ResMut<MeshBufferPool>,
     root: Res<RootGrid>,
+    atlas: Res<VoxelTextureAtlas>,
 ) {
     // map ChunkKey → (entity, mesh-handle, material-handle)
     let existing: HashMap<ChunkKey, (Entity, Handle<Mesh>, Handle<StandardMaterial>, u32)> =
@@ -87,7 +89,7 @@ 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
-                match mesh_chunk(&buf, origin, step, &tree, &mut pool) {
+                match mesh_chunk(&buf, origin, step, &tree, &mut pool, &atlas) {
                     Some(new_mesh) => {
                         if let Some(mesh) = meshes.get_mut(&mesh_h) {
                             *mesh = new_mesh;
@@ -100,10 +102,13 @@ pub fn rebuild_dirty_chunks(
                         spawned.0.remove(&key);
                     }
                 }
-            } else if let Some(mesh) = mesh_chunk(&buf, origin, step, &tree, &mut pool) {
+            } else if let Some(mesh) = mesh_chunk(&buf, origin, step, &tree, &mut pool, &atlas) {
                 // spawn brand-new chunk only if mesh has faces
                 let mesh_h = meshes.add(mesh);
-                let mat_h = materials.add(StandardMaterial::default());
+                let mat_h = materials.add(StandardMaterial {
+                    base_color_texture: Some(atlas.handle.clone()),
+                    ..Default::default()
+                });
 
                 commands.entity(root.0).with_children(|p| {
                     let e = p

client/src/plugins/environment/systems/voxels/structure.rs

@@ -1,32 +1,21 @@
-use bevy::color::Color;
 use bevy::prelude::*;
-use serde::{Deserialize, Deserializer, Serialize, Serializer};
+use rand::Rng;
+use serde::{Deserialize, Serialize};
 use std::collections::{HashMap, HashSet, VecDeque};
 
-fn serialize_color<S>(color: &Color, serializer: S) -> Result<S::Ok, S::Error>
-where
-    S: Serializer,
-{
-    let [r, g, b, a] = color.to_linear().to_f32_array();
-    [r, g, b, a].serialize(serializer)
-}
-
-fn deserialize_color<'de, D>(deserializer: D) -> Result<Color, D::Error>
-where
-    D: Deserializer<'de>,
-{
-    let arr: [f32; 4] = Deserialize::deserialize(deserializer)?;
-    Ok(Color::linear_rgba(arr[0], arr[1], arr[2], arr[3]))
-}
-
-/// Represents a single voxel with a color.
-#[derive(Debug, Clone, Copy, Component, PartialEq, Default, Serialize, Deserialize)]
+/// Represents a single voxel with texture indices for each face.
+#[derive(Debug, Clone, Copy, Component, PartialEq, Serialize, Deserialize)]
 pub struct Voxel {
-    #[serde(
-        serialize_with = "serialize_color",
-        deserialize_with = "deserialize_color"
-    )]
-    pub color: Color,
+    /// Indexes into the texture atlas for the six faces in the order
+    /// left, right, bottom, top, back, front.
+    #[serde(default)]
+    pub textures: [usize; 6],
+}
+
+impl Default for Voxel {
+    fn default() -> Self {
+        Self { textures: [0; 6] }
+    }
 }
 
 #[derive(Debug, Clone, Copy)]
@@ -77,8 +66,23 @@ impl OctreeNode {
 
 impl Voxel {
     /// Creates a new empty octree node.
-    pub fn new(color: Color) -> Self {
-        Self { color }
+    pub fn new(textures: [usize; 6]) -> Self {
+        Self { textures }
+    }
+
+    /// Generate a voxel with a red top, black bottom and random colors on
+    /// all remaining faces. Assumes the atlas uses index 0 for red, index 1
+    /// for black and indices >=2 for random colors.
+    pub fn random_sides() -> Self {
+        let mut rng = rand::thread_rng();
+        let mut textures = [0usize; 6];
+        // Face order: left, right, bottom, top, back, front
+        textures[3] = 0; // top is red
+        textures[2] = 1; // bottom is black
+        for &i in &[0usize, 1usize, 4usize, 5usize] {
+            textures[i] = rng.gen_range(2..6);
+        }
+        Self { textures }
     }
 }
 

client/src/plugins/input/systems/voxels.rs

@@ -1,12 +1,11 @@
-use std::path::Path;
-use bevy::prelude::*;
 use crate::plugins::environment::systems::camera_system::CameraController;
 use crate::plugins::environment::systems::voxels::octree;
 use crate::plugins::environment::systems::voxels::structure::*;
+use bevy::prelude::*;
+use std::path::Path;
 
 ///TODO
 pub fn voxel_system(
-
     keyboard_input: Res<ButtonInput<KeyCode>>,
     mouse_button_input: Res<ButtonInput<MouseButton>>,
     mut octree_query: Query<&mut SparseVoxelOctree>,
@@ -14,29 +13,33 @@ pub fn voxel_system(
     mut query: Query<(&mut Transform, &mut CameraController)>,
     mut windows: Query<&mut Window>,
 ) {
-    let Ok(mut window) = windows.get_single_mut() else { return };
-    let Ok((mut transform, _)) = query.get_single_mut() else { return };
+    let Ok(mut window) = windows.get_single_mut() else {
+        return;
+    };
+    let Ok((mut transform, _)) = query.get_single_mut() else {
+        return;
+    };
 
     // =======================
     // 5) Octree Keys
     // =======================
-    if keyboard_input.just_pressed(KeyCode::F2){
+    if keyboard_input.just_pressed(KeyCode::F2) {
         for mut octree in octree_query.iter_mut() {
             octree.show_wireframe = !octree.show_wireframe;
         }
     }
-    if keyboard_input.just_pressed(KeyCode::F3){
+    if keyboard_input.just_pressed(KeyCode::F3) {
         for mut octree in octree_query.iter_mut() {
             octree.show_world_grid = !octree.show_world_grid;
         }
     }
 
-    if keyboard_input.just_pressed(KeyCode::KeyQ) && window.cursor_options.visible == false{
+    if keyboard_input.just_pressed(KeyCode::KeyQ) && window.cursor_options.visible == false {
         for mut octree in octree_query.iter_mut() {
-            octree.insert(transform.translation, Voxel::new(Color::srgb(1.0, 0.0, 0.0)));
+            octree.insert(transform.translation, Voxel::random_sides());
         }
     }
-    if keyboard_input.just_pressed(KeyCode::F4){
+    if keyboard_input.just_pressed(KeyCode::F4) {
         let path = Path::new("octree.bin");
         for octree in octree_query.iter() {
             if let Err(e) = octree.save_to_file(path) {
@@ -44,7 +47,7 @@ pub fn voxel_system(
             }
         }
     }
-/*    if keyboard_input.just_pressed(KeyCode::F5){
+    /*    if keyboard_input.just_pressed(KeyCode::F5){
         let path = Path::new("octree.bin");
         if path.exists() {
             let path = Path::new("octree.bin");
@@ -57,17 +60,18 @@ pub fn voxel_system(
                     }
                 }
             }
-            
+
         }
     }*/
 
-
     // =======================
     // 6) Building
     // =======================
 
-    if (mouse_button_input.just_pressed(MouseButton::Left) || mouse_button_input.just_pressed(MouseButton::Right)) && !window.cursor_options.visible {
-
+    if (mouse_button_input.just_pressed(MouseButton::Left)
+        || mouse_button_input.just_pressed(MouseButton::Right))
+        && !window.cursor_options.visible
+    {
         // Get the mouse position in normalized device coordinates (-1 to 1)
         if let Some(_) = window.cursor_position() {
             // Set the ray direction to the camera's forward vector
@@ -79,44 +83,33 @@ pub fn voxel_system(
                 direction: ray_direction,
             };
 
-
-
             for mut octree in octree_query.iter_mut() {
-                if let Some((hit_x, hit_y, hit_z, depth,normal)) = octree.raycast(&ray) {
-
-
+                if let Some((hit_x, hit_y, hit_z, depth, normal)) = octree.raycast(&ray) {
                     if mouse_button_input.just_pressed(MouseButton::Right) {
-
                         let voxel_size = octree.get_spacing_at_depth(depth);
                         let hit_position = Vec3::new(hit_x as f32, hit_y as f32, hit_z as f32);
                         let epsilon = voxel_size * 0.1; // Adjust this value as needed (e.g., 0.1 times the voxel size)
 
                         // Offset position by epsilon in the direction of the normal
-                        let offset_position = hit_position - (normal * Vec3::new(epsilon as f32, epsilon as f32, epsilon as f32));
+                        let offset_position = hit_position
+                            - (normal * Vec3::new(epsilon as f32, epsilon as f32, epsilon as f32));
 
                         // Remove the voxel
                         octree.remove(offset_position);
-
-
-                    }
-                    else if mouse_button_input.just_pressed(MouseButton::Left) {
-
+                    } else if mouse_button_input.just_pressed(MouseButton::Left) {
                         let voxel_size = octree.get_spacing_at_depth(depth);
                         let hit_position = Vec3::new(hit_x as f32, hit_y as f32, hit_z as f32);
                         let epsilon = voxel_size * 0.1; // Adjust this value as needed (e.g., 0.1 times the voxel size)
 
                         // Offset position by epsilon in the direction of the normal
-                        let offset_position = hit_position + (normal * Vec3::new(epsilon as f32, epsilon as f32, epsilon as f32));
+                        let offset_position = hit_position
+                            + (normal * Vec3::new(epsilon as f32, epsilon as f32, epsilon as f32));
 
                         // Insert the new voxel
-                        octree.insert(
-                            offset_position,
-                            Voxel::new(Color::srgb(1.0, 0.0, 0.0)),
-                        );
+                        octree.insert(offset_position, Voxel::random_sides());
                     }
                 }
             }
         }
     }
-    
-}
+}