From 34400932847d03a80f19dca655ac45c8bf09f9da Mon Sep 17 00:00:00 2001
From: Elias Stepanik <eliasstepanik@proton.me>
Date: Sun, 8 Jun 2025 06:50:47 +0200
Subject: [PATCH] Added Greedy Mesher + tracy profile

---
 .idea/runConfigurations/Run_horror_game.xml   |   4 +-
 client/Cargo.toml                             |   3 +-
 .../plugins/environment/environment_plugin.rs |   7 +-
 .../environment/systems/voxels/culling.rs     |  37 ++--
 .../environment/systems/voxels/helper.rs      |  59 ++++++
 .../environment/systems/voxels/meshing.rs     | 181 +++++++++++++++++-
 .../systems/voxels/render_chunks.rs           |  84 ++++----
 .../environment/systems/voxels/structure.rs   |   1 +
 8 files changed, 317 insertions(+), 59 deletions(-)

diff --git a/.idea/runConfigurations/Run_horror_game.xml b/.idea/runConfigurations/Run_horror_game.xml
index dea1c47..2cf0f3e 100644
--- a/.idea/runConfigurations/Run_horror_game.xml
+++ b/.idea/runConfigurations/Run_horror_game.xml
@@ -1,7 +1,7 @@
 <component name="ProjectRunConfigurationManager">
   <configuration default="false" name="Run horror-game" type="CargoCommandRunConfiguration" factoryName="Cargo Command" singleton="false">
-    <option name="buildProfileId" value="dev" />
-    <option name="command" value="run --package horror-game --bin horror-game" />
+    <option name="buildProfileId" value="release" />
+    <option name="command" value="run --package horror-game --bin horror-game --features bevy/trace_tracy_memory" />
     <option name="workingDirectory" value="file://$PROJECT_DIR$/client" />
     <envs />
     <option name="emulateTerminal" value="true" />
diff --git a/client/Cargo.toml b/client/Cargo.toml
index 24a1aaf..125b5fc 100644
--- a/client/Cargo.toml
+++ b/client/Cargo.toml
@@ -17,4 +17,5 @@ big_space = "0.9.1"
 noise = "0.9.0"
 itertools = "0.13.0"
 bitvec = "1.0.1"
-smallvec = "1.14.0"
\ No newline at end of file
+smallvec = "1.14.0"
+once_cell = "1.21.3"
\ No newline at end of file
diff --git a/client/src/plugins/environment/environment_plugin.rs b/client/src/plugins/environment/environment_plugin.rs
index 1c93000..1f6aa6d 100644
--- a/client/src/plugins/environment/environment_plugin.rs
+++ b/client/src/plugins/environment/environment_plugin.rs
@@ -23,7 +23,7 @@ impl Plugin for EnvironmentPlugin {
 
         app.insert_resource(ChunkCullingCfg { view_distance_chunks: 10 });
         app.insert_resource(ChunkBudget { per_frame: 20 });
-        
+        app.add_systems(Update, log_mesh_count);
         app
             // ------------------------------------------------------------------------
             // resources
@@ -56,6 +56,11 @@ impl Plugin for EnvironmentPlugin {
     }
 }
 
+fn log_mesh_count(meshes: Res<Assets<Mesh>>, time: Res<Time>) {
+    if time.delta_secs_f64() as i32 % 5 == 0 {
+        info!("meshes: {}", meshes.len());
+    }
+}
 
 fn should_visualize_octree(octree_query: Query<&SparseVoxelOctree>,) -> bool {
     octree_query.single().show_wireframe
diff --git a/client/src/plugins/environment/systems/voxels/culling.rs b/client/src/plugins/environment/systems/voxels/culling.rs
index 6f98290..103ebdc 100644
--- a/client/src/plugins/environment/systems/voxels/culling.rs
+++ b/client/src/plugins/environment/systems/voxels/culling.rs
@@ -8,25 +8,34 @@ use crate::plugins::environment::systems::voxels::structure::*;
 /// configured radius
 
 pub fn despawn_distant_chunks(
-    mut commands   : Commands,
-    cam_q          : Query<&GlobalTransform, With<Camera>>,
-    tree_q         : Query<&SparseVoxelOctree>,
-    mut spawned    : ResMut<SpawnedChunks>,
-    chunk_q        : Query<&Chunk>,
-    cfg            : Res<ChunkCullingCfg>,
+    mut commands : Commands,
+    cam_q        : Query<&GlobalTransform, With<Camera>>,
+    tree_q       : Query<&SparseVoxelOctree>,
+    mut spawned  : ResMut<SpawnedChunks>,
+    chunk_q      : Query<(Entity,
+                          &Chunk,
+                          &Mesh3d,
+                          &MeshMaterial3d<StandardMaterial>)>,
+    mut meshes   : ResMut<Assets<Mesh>>,
+    mut materials: ResMut<Assets<StandardMaterial>>,
+    cfg          : Res<ChunkCullingCfg>,
 ) {
     let tree   = tree_q.single();
     let cam    = cam_q.single().translation();
-    let center = world_to_chunk(tree, cam);
+    let centre = world_to_chunk(tree, cam);
 
-    for chunk in chunk_q.iter() {
+    for (ent, chunk, mesh3d, mat3d) in chunk_q.iter() {
         let ChunkKey(x, y, z) = chunk.key;
-        if  (x - center.0).abs() > cfg.view_distance_chunks ||
-            (y - center.1).abs() > cfg.view_distance_chunks ||
-            (z - center.2).abs() > cfg.view_distance_chunks {
-            if let Some(ent) = spawned.0.remove(&chunk.key) {
-                commands.entity(ent).despawn_recursive();
-            }
+        if  (x - centre.0).abs() > cfg.view_distance_chunks ||
+            (y - centre.1).abs() > cfg.view_distance_chunks ||
+            (z - centre.2).abs() > cfg.view_distance_chunks {
+
+            // free assets – borrow, don't move
+            meshes.remove(&mesh3d.0);
+            materials.remove(&mat3d.0);
+
+            commands.entity(ent).despawn_recursive();
+            spawned.0.remove(&chunk.key);
         }
     }
 }
\ No newline at end of file
diff --git a/client/src/plugins/environment/systems/voxels/helper.rs b/client/src/plugins/environment/systems/voxels/helper.rs
index 6279d4f..b865e17 100644
--- a/client/src/plugins/environment/systems/voxels/helper.rs
+++ b/client/src/plugins/environment/systems/voxels/helper.rs
@@ -269,3 +269,62 @@ pub fn world_to_chunk(tree: &SparseVoxelOctree, p: Vec3) -> ChunkKey {
     )
 }
 
+impl AABB {
+    pub fn intersects_aabb(&self, other: &AABB) -> bool {
+        self.min.x <= other.max.x &&
+            self.max.x >= other.min.x &&
+            self.min.y <= other.max.y &&
+            self.max.y >= other.min.y &&
+            self.min.z <= other.max.z &&
+            self.max.z >= other.min.z
+    }
+
+    pub fn center(&self) -> Vec3 {
+        (self.min + self.max) * 0.5
+    }
+}
+
+impl SparseVoxelOctree {
+    pub fn collect_voxels_in_region(&self, min: Vec3, max: Vec3) -> Vec<(Vec3, Voxel)> {
+        let half_size = self.size * 0.5;
+        let root_bounds = AABB {
+            min: Vec3::new(-half_size, -half_size, -half_size),
+            max: Vec3::new(half_size, half_size, half_size),
+        };
+        let mut voxels = Vec::new();
+        self.collect_voxels_in_region_recursive(&self.root, root_bounds, min, max, &mut voxels);
+        voxels
+    }
+
+    fn collect_voxels_in_region_recursive(
+        &self,
+        node: &OctreeNode,
+        node_bounds: AABB,
+        min: Vec3,
+        max: Vec3,
+        out: &mut Vec<(Vec3, Voxel)>,
+    ) {
+        if !node_bounds.intersects_aabb(&AABB { min, max }) {
+            return;
+        }
+
+        if node.is_leaf {
+            if let Some(voxel) = &node.voxel {
+                let center = node_bounds.center();
+                if center.x >= min.x && center.x <= max.x &&
+                    center.y >= min.y && center.y <= max.y &&
+                    center.z >= min.z && center.z <= max.z
+                {
+                    out.push((center, *voxel));
+                }
+            }
+        }
+
+        if let Some(children) = &node.children {
+            for (i, child) in children.iter().enumerate() {
+                let child_bounds = self.compute_child_bounds(&node_bounds, i);
+                self.collect_voxels_in_region_recursive(child, child_bounds, min, max, out);
+            }
+        }
+    }
+}
\ No newline at end of file
diff --git a/client/src/plugins/environment/systems/voxels/meshing.rs b/client/src/plugins/environment/systems/voxels/meshing.rs
index e006013..1a0ff45 100644
--- a/client/src/plugins/environment/systems/voxels/meshing.rs
+++ b/client/src/plugins/environment/systems/voxels/meshing.rs
@@ -3,7 +3,7 @@ use bevy::prelude::*;
 use bevy::render::mesh::{Indices, PrimitiveTopology, VertexAttributeValues, Mesh};
 use crate::plugins::environment::systems::voxels::structure::*;
 
-pub(crate) fn mesh_chunk(
+/*pub(crate) fn mesh_chunk(
     buffer: &[[[Option<Voxel>; CHUNK_SIZE as usize]; CHUNK_SIZE as usize]; CHUNK_SIZE as usize],
     origin: Vec3,
     step:   f32,
@@ -296,4 +296,181 @@ pub(crate) fn mesh_chunk(
     mesh.insert_attribute(Mesh::ATTRIBUTE_UV_0,     VertexAttributeValues::Float32x2(uvs));
     mesh.insert_indices(Indices::U32(indices));
     mesh
-}
\ No newline at end of file
+}*/
+
+
+pub(crate) fn mesh_chunk(
+    buffer: &[[[Option<Voxel>; CHUNK_SIZE as usize]; CHUNK_SIZE as usize]; CHUNK_SIZE as usize],
+    origin: Vec3,
+    step:   f32,
+    tree:   &SparseVoxelOctree,
+) -> Mesh {
+    // ────────────────────────────────────────────────────────────────────────────
+    // Helpers
+    // ────────────────────────────────────────────────────────────────────────────
+
+    const N: usize = CHUNK_SIZE as usize;
+
+    // Safe voxel query that falls back to the octree for out‑of‑chunk requests.
+    let filled = |x: i32, y: i32, z: i32| -> bool {
+        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()
+        } 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()
+        }
+    };
+
+    // Push a single quad (4 vertices, 6 indices).  `base` is the lower‑left
+    // corner in world space; `u`/`v` are the tangent vectors (length 1); `size`
+    // is expressed in world units along those axes; `n` is the face normal.
+    let mut positions = Vec::<[f32; 3]>::new();
+    let mut normals   = Vec::<[f32; 3]>::new();
+    let mut uvs       = Vec::<[f32; 2]>::new();
+    let mut indices   = Vec::<u32>::new();
+
+    let mut push_quad = |base: Vec3, size: Vec2, n: Vec3, u: Vec3, v: Vec3| {
+        let i0 = positions.len() as u32;
+        positions.extend_from_slice(&[
+            (base).into(),
+            (base + u * size.x).into(),
+            (base + u * size.x + v * size.y).into(),
+            (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]]);
+
+        if n.x + n.y + n.z >= 0.0 {
+            indices.extend_from_slice(&[i0, i0 + 1, i0 + 2, i0 + 2, i0 + 3, i0]);
+        } else {
+            // Flip winding for faces with a negative normal component sum so the
+            // result is still counter‑clockwise.
+            indices.extend_from_slice(&[i0, i0 + 3, i0 + 2, i0 + 2, i0 + 1, i0]);
+        }
+    };
+
+    // ────────────────────────────────────────────────────────────────────────────
+    // Greedy meshing
+    // ────────────────────────────────────────────────────────────────────────────
+
+    // Axes: 0→X, 1→Y, 2→Z.  For each axis we process the negative and positive
+    // faces (dir = −1 / +1).
+    for (axis, dir) in [ (0, -1), (0, 1), (1, -1), (1, 1), (2, -1), (2, 1) ] {
+        // Mapping of (u,v) axes and their unit vectors in world space.
+        let (u_axis, v_axis, face_normal, u_vec, v_vec) = match (axis, dir) {
+            (0, d) => (1, 2, Vec3::new(d as f32, 0.0, 0.0), Vec3::Y, Vec3::Z),
+            (1, d) => (2, 0, Vec3::new(0.0, d as f32, 0.0), Vec3::Z, Vec3::X),
+            (2, d) => (0, 1, Vec3::new(0.0, 0.0, d as f32), Vec3::X, Vec3::Y),
+            _ => unreachable!(),
+        };
+
+        // Iterate over every slice perpendicular to `axis`.  Faces can lie on
+        // the 0…N grid lines (inclusive) because the positive‑side faces of the
+        // last voxel sit at slice N.
+        for slice in 0..=N {
+            // Build the face mask for this slice.
+            let mut mask = vec![false; N * N];
+            let idx = |u: usize, v: usize| -> usize { u * N + v };
+
+            for u in 0..N {
+                for v in 0..N {
+                    // Translate (u,v,slice) to (x,y,z) voxel coordinates.
+                    let mut cell = [0i32; 3];
+                    let mut neighbor = [0i32; 3];
+
+                    cell [axis] = slice as i32 + if dir == 1 { -1 } else { 0 };
+                    neighbor[axis] = cell[axis] + dir;
+
+                    cell [u_axis] = u as i32;
+                    cell [v_axis] = v as i32;
+                    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;
+                    }
+                }
+            }
+
+            // Greedy merge the mask into maximal rectangles.
+            let mut visited = vec![false; N * N];
+            for u0 in 0..N {
+                for v0 in 0..N {
+                    if !mask[idx(u0, v0)] || visited[idx(u0, v0)] {
+                        continue;
+                    }
+
+                    // Determine the rectangle width.
+                    let mut width = 1;
+                    while u0 + width < N && mask[idx(u0 + width, v0)] && !visited[idx(u0 + width, v0)] {
+                        width += 1;
+                    }
+
+                    // Determine the rectangle height.
+                    let mut height = 1;
+                    'h: while v0 + height < N {
+                        for du in 0..width {
+                            if !mask[idx(u0 + du, v0 + height)] || visited[idx(u0 + du, v0 + height)] {
+                                break 'h;
+                            }
+                        }
+                        height += 1;
+                    }
+
+                    // Mark the rectangle area as visited.
+                    for du in 0..width {
+                        for dv in 0..height {
+                            visited[idx(u0 + du, v0 + dv)] = true;
+                        }
+                    }
+
+                    // Compute world‑space base corner.
+                    let mut base = origin;
+                    match axis {
+                        0 => {
+                            base.x += step * slice as f32;
+                            base.y += step * u0 as f32;
+                            base.z += step * v0 as f32;
+                        }
+                        1 => {
+                            base.x += step * v0 as f32;
+                            base.y += step * slice as f32;
+                            base.z += step * u0 as f32;
+                        }
+                        2 => {
+                            base.x += step * u0 as f32;
+                            base.y += step * v0 as f32;
+                            base.z += step * slice as f32;
+                        }
+                        _ => unreachable!(),
+                    }
+
+                    let size = Vec2::new(width as f32 * step, height as f32 * step);
+                    push_quad(base, size, face_normal, u_vec, v_vec);
+                }
+            }
+        }
+    }
+
+    // ────────────────────────────────────────────────────────────────────────────
+    // Final mesh assembly
+    // ────────────────────────────────────────────────────────────────────────────
+    let mut mesh = Mesh::new(PrimitiveTopology::TriangleList, RenderAssetUsages::default());
+    mesh.insert_attribute(
+        Mesh::ATTRIBUTE_POSITION,
+        VertexAttributeValues::Float32x3(positions),
+    );
+    mesh.insert_attribute(
+        Mesh::ATTRIBUTE_NORMAL,
+        VertexAttributeValues::Float32x3(normals),
+    );
+    mesh.insert_attribute(
+        Mesh::ATTRIBUTE_UV_0,
+        VertexAttributeValues::Float32x2(uvs),
+    );
+    mesh.insert_indices(Indices::U32(indices));
+    mesh
+}
diff --git a/client/src/plugins/environment/systems/voxels/render_chunks.rs b/client/src/plugins/environment/systems/voxels/render_chunks.rs
index 9cedb11..bcdf2fd 100644
--- a/client/src/plugins/environment/systems/voxels/render_chunks.rs
+++ b/client/src/plugins/environment/systems/voxels/render_chunks.rs
@@ -1,5 +1,6 @@
 use std::collections::HashMap;
 use std::fmt::format;
+use bevy::pbr::wireframe::Wireframe;
 use bevy::prelude::*;
 use bevy::render::mesh::Mesh;
 use big_space::prelude::GridCell;
@@ -7,41 +8,41 @@ use itertools::Itertools;
 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::*;
+
 /// rebuilds meshes only for chunks flagged dirty by the octree
 pub fn rebuild_dirty_chunks(
-    mut commands:   Commands,
-    mut octrees:    Query<(Entity, &mut SparseVoxelOctree)>,
-    mut meshes:     ResMut<Assets<Mesh>>,
-    mut materials:  ResMut<Assets<StandardMaterial>>,
-    chunk_q:        Query<(Entity, &Chunk)>,
-    mut spawned    : ResMut<SpawnedChunks>,
-    root:           Res<RootGrid>,
+    mut commands : Commands,
+    mut octrees  : Query<&mut SparseVoxelOctree>,
+    mut meshes   : ResMut<Assets<Mesh>>,
+    mut materials: ResMut<Assets<StandardMaterial>>,
+    chunk_q      : Query<(Entity,
+                          &Chunk,
+                          &Mesh3d,
+                          &MeshMaterial3d<StandardMaterial>)>,
+    mut spawned  : ResMut<SpawnedChunks>,
+    root         : Res<RootGrid>,
 ) {
-    // map ChunkKey → entity
-    
-    let existing: HashMap<ChunkKey, Entity> =
-        chunk_q.iter().map(|(e, c)| (c.key, e)).collect();
+    // map ChunkKey → (entity, mesh-handle, material-handle)
+    let existing: HashMap<ChunkKey, (Entity, Handle<Mesh>, Handle<StandardMaterial>)> =
+        chunk_q
+            .iter()
+            .map(|(e, c, m, mat)| (c.key, (e, m.0.clone(), mat.0.clone())))
+            .collect();
 
-    for (_tree_ent, mut tree) in &mut octrees {
+    for mut tree in &mut octrees {
         if tree.dirty_chunks.is_empty() {
             continue;
         }
 
-        // gather voxel data for every dirty chunk
-        let mut chunk_voxel_bufs: Vec<(
-            ChunkKey,
-            [[[Option<Voxel>; CHUNK_SIZE as usize]; CHUNK_SIZE as usize]; CHUNK_SIZE as usize],
-            Vec3, // chunk origin
-            f32,  // voxel step
-        )> = Vec::new();
-
+        //------------------------------------------------ collect voxel data
+        let mut bufs = Vec::new();
         for key in tree.dirty_chunks.iter().copied() {
             let mut buf =
                 [[[None; CHUNK_SIZE as usize]; CHUNK_SIZE as usize]; CHUNK_SIZE as usize];
 
             let half = tree.size * 0.5;
             let step = tree.get_spacing_at_depth(tree.max_depth);
-            let start = Vec3::new(
+            let origin = Vec3::new(
                 key.0 as f32 * CHUNK_SIZE as f32 * step - half,
                 key.1 as f32 * CHUNK_SIZE as f32 * step - half,
                 key.2 as f32 * CHUNK_SIZE as f32 * step - half,
@@ -50,7 +51,7 @@ pub fn rebuild_dirty_chunks(
             for lx in 0..CHUNK_SIZE {
                 for ly in 0..CHUNK_SIZE {
                     for lz in 0..CHUNK_SIZE {
-                        let world = start
+                        let world = origin
                             + Vec3::new(lx as f32 * step, ly as f32 * step, lz as f32 * step);
                         if let Some(v) = tree.get_voxel_at_world_coords(world) {
                             buf[lx as usize][ly as usize][lz as usize] = Some(*v);
@@ -59,28 +60,33 @@ pub fn rebuild_dirty_chunks(
                 }
             }
 
-            chunk_voxel_bufs.push((key, buf, start, step));
+            bufs.push((key, buf, origin, step));
         }
 
-        // build / replace meshes
-        for (key, buf, origin, step) in chunk_voxel_bufs {
-            let mesh_handle =
-                meshes.add(mesh_chunk(&buf, origin, step, &tree));
-            let mesh_3d     = Mesh3d::from(mesh_handle);
-            let material    = MeshMaterial3d::<StandardMaterial>::default();
-
-            if let Some(&ent) = existing.get(&key) {
-                commands.entity(ent).insert(mesh_3d);
+        //------------------------------------------------ create / update
+        for (key, buf, origin, step) 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);
+                }
                 spawned.0.insert(key, ent);
             } else {
+                // spawn brand-new chunk
+                let mesh_h = meshes.add(mesh_chunk(&buf, origin, step, &tree));
+                let mat_h  = materials.add(StandardMaterial::default());
+
                 commands.entity(root.0).with_children(|p| {
-                    let e = p.spawn((
-                        mesh_3d,
-                        material,
-                        Transform::default(),
-                        GridCell::<i64>::ZERO,
-                        Chunk { key, voxels: Vec::new(), dirty: false },
-                    )).id();
+                    let e = p
+                        .spawn((
+                            Mesh3d::from(mesh_h.clone()),
+                            MeshMaterial3d(mat_h.clone()),
+                            Transform::default(),
+                            GridCell::<i64>::ZERO,
+                            Chunk { key, voxels: Vec::new(), dirty: false },
+                            /*Wireframe,*/
+                        ))
+                        .id();
                     spawned.0.insert(key, e);
                 });
             }
diff --git a/client/src/plugins/environment/systems/voxels/structure.rs b/client/src/plugins/environment/systems/voxels/structure.rs
index 731afff..9ebc72d 100644
--- a/client/src/plugins/environment/systems/voxels/structure.rs
+++ b/client/src/plugins/environment/systems/voxels/structure.rs
@@ -93,6 +93,7 @@ pub struct Chunk {
     pub key: ChunkKey,
     pub voxels: Vec<(IVec3, Voxel)>,   // local coords 0‥15
     pub dirty: bool,
+    
 }