VoxelInstancer supports VoxelTerrain, although Godot 4 multimeshes are buggy

See https://github.com/godotengine/godot/issues/56357

doc/source/changelog.md

@@ -27,6 +27,7 @@ Godot 4 is required from this version.
     - `VoxelGeneratorGraph`: added math expression node
     - `VoxelGeneratorGraph`: added Pow and Powi nodes
     - `VoxelGeneratorGraph`: Clamp now accepts min and max as inputs. For the version with constant parameters, use ClampC (might be faster in the current state of things).
+    - `VoxelInstancer`: Added support for `VoxelTerrain`. This means only LOD0 works, but mesh-LODs should work.
 
 - Smooth voxels
     - SDF data is now encoded with `inorm8` and `inorm16`, instead of an arbitrary version of `unorm8` and `unorm16`. Migration code is in place to load old save files, but *do a backup before running your project with the new version*.

terrain/fixed_lod/voxel_terrain.cpp

@@ -9,6 +9,7 @@
 #include "../../util/macros.h"
 #include "../../util/profiling.h"
 #include "../../util/profiling_clock.h"
+#include "../instancing/voxel_instancer.h"
 #include "../voxel_data_block_enter_info.h"
 
 #include <core/config/engine.h>
@@ -217,6 +218,13 @@ void VoxelTerrain::set_mesh_block_size(unsigned int mesh_block_size) {
 
 	_mesh_block_size_po2 = po2;
 
+	if (_instancer != nullptr) {
+		VoxelInstancer &instancer = *_instancer;
+		_mesh_map.for_each_block([&instancer](VoxelMeshBlockVT &block) { //
+			instancer.on_mesh_block_exit(block.position, 0);
+		});
+	}
+
 	// Unload all mesh blocks regardless of refcount
 	_mesh_map.clear();
 
@@ -356,6 +364,10 @@ unsigned int VoxelTerrain::get_max_view_distance() const {
 void VoxelTerrain::set_max_view_distance(unsigned int distance_in_voxels) {
 	ERR_FAIL_COND(distance_in_voxels < 0);
 	_max_view_distance_voxels = distance_in_voxels;
+
+	if (_instancer != nullptr) {
+		_instancer->set_mesh_lod_distance(_max_view_distance_voxels);
+	}
 }
 
 void VoxelTerrain::set_block_enter_notification_enabled(bool enable) {
@@ -401,8 +413,9 @@ void VoxelTerrain::set_material(unsigned int id, Ref<Material> material) {
 		_mesh_map.for_each_block([material, old_material](VoxelMeshBlockVT &block) {
 			Ref<Mesh> mesh = block.get_mesh();
 			if (mesh.is_valid()) {
-				// We can't just assign by material index because some meshes don't use all materials of the terrain,
-				// therefore they don't have as many surfaces. So we have to find which surfaces use the old material.
+				// We can't just assign by material index because some meshes don't use all materials of the
+				// terrain, therefore they don't have as many surfaces. So we have to find which surfaces use the
+				// old material.
 				for (int surface_index = 0; surface_index < mesh->get_surface_count(); ++surface_index) {
 					if (mesh->surface_get_material(surface_index) == old_material) {
 						mesh->surface_set_material(surface_index, material);
@@ -640,16 +653,25 @@ void VoxelTerrain::unload_mesh_block(Vector3i bpos) {
 
 	_mesh_map.remove_block(bpos, [&blocks_pending_update](const VoxelMeshBlockVT &block) {
 		if (block.get_mesh_state() == VoxelMeshBlockVT::MESH_UPDATE_NOT_SENT) {
-			// That block was in the list of blocks to update later in the process loop, we'll need to unregister it.
-			// We expect that block to be in that list. If it isn't, something wrong happened with its state.
+			// That block was in the list of blocks to update later in the process loop, we'll need to unregister
+			// it. We expect that block to be in that list. If it isn't, something wrong happened with its state.
 			ERR_FAIL_COND(!unordered_remove_value(blocks_pending_update, block.position));
 		}
 	});
+
+	if (_instancer != nullptr) {
+		_instancer->on_mesh_block_exit(bpos, 0);
+	}
 }
 
 void VoxelTerrain::save_all_modified_blocks(bool with_copy) {
 	// That may cause a stutter, so should be used when the player won't notice
 	_data_map.for_each_block(ScheduleSaveAction{ _blocks_to_save, with_copy });
+
+	if (_stream.is_valid() && _instancer != nullptr && _stream->supports_instance_blocks()) {
+		_instancer->save_all_modified_blocks();
+	}
+
 	// And flush immediately
 	send_block_data_requests();
 }
@@ -658,6 +680,42 @@ const VoxelTerrain::Stats &VoxelTerrain::get_stats() const {
 	return _stats;
 }
 
+void VoxelTerrain::set_instancer(VoxelInstancer *instancer) {
+	if (_instancer != nullptr && instancer != nullptr) {
+		ERR_FAIL_COND_MSG(_instancer != nullptr, "No more than one VoxelInstancer per terrain");
+	}
+	_instancer = instancer;
+}
+
+void VoxelTerrain::get_meshed_block_positions(std::vector<Vector3i> &out_positions) const {
+	_mesh_map.for_each_block([&out_positions](const VoxelMeshBlock &mesh_block) {
+		if (mesh_block.has_mesh()) {
+			out_positions.push_back(mesh_block.position);
+		}
+	});
+}
+
+// This function is primarily intented for editor use cases at the moment.
+// It will be slower than using the instancing generation events,
+// because it has to query VisualServer, which then allocates and decodes vertex buffers (assuming they are cached).
+Array VoxelTerrain::get_mesh_block_surface(Vector3i block_pos) const {
+	ZN_PROFILE_SCOPE();
+
+	Ref<Mesh> mesh;
+	{
+		const VoxelMeshBlockVT *block = _mesh_map.get_block(block_pos);
+		if (block != nullptr) {
+			mesh = block->get_mesh();
+		}
+	}
+
+	if (mesh.is_valid()) {
+		return mesh->surface_get_arrays(0);
+	}
+
+	return Array();
+}
+
 Dictionary VoxelTerrain::_b_get_statistics() const {
 	Dictionary d;
 
@@ -811,6 +869,10 @@ void VoxelTerrain::post_edit_area(Box3i box_in_voxels) {
 	}
 
 	try_schedule_mesh_update_from_data(box_in_voxels);
+
+	if (_instancer != nullptr) {
+		_instancer->on_area_edited(box_in_voxels);
+	}
 }
 
 void VoxelTerrain::_notification(int p_what) {
@@ -887,7 +949,7 @@ void VoxelTerrain::send_block_data_requests() {
 	for (size_t i = 0; i < _blocks_pending_load.size(); ++i) {
 		const Vector3i block_pos = _blocks_pending_load[i];
 		// TODO Batch request
-		VoxelServer::get_singleton().request_block_load(_volume_id, block_pos, 0, false);
+		VoxelServer::get_singleton().request_block_load(_volume_id, block_pos, 0, _instancer != nullptr);
 	}
 
 	// Blocks to save
@@ -1275,11 +1337,15 @@ void VoxelTerrain::apply_data_block_response(VoxelServer::BlockDataOutput &ob) {
 	// if (stream_enabled) {
 	// 	send_block_data_requests();
 	// }
+
+	if (_instancer != nullptr && ob.instances != nullptr) {
+		_instancer->on_data_block_loaded(ob.position, ob.lod, std::move(ob.instances));
+	}
 }
 
 // Sets voxel data of a block, discarding existing data if any.
-// If the given block coordinates are not inside any viewer's area, this function won't do anything and return false.
-// If a block is already loading or generating at this position, it will be cancelled.
+// If the given block coordinates are not inside any viewer's area, this function won't do anything and return
+// false. If a block is already loading or generating at this position, it will be cancelled.
 bool VoxelTerrain::try_set_block_data(Vector3i position, std::shared_ptr<VoxelBufferInternal> &voxel_data) {
 	ZN_PROFILE_SCOPE();
 	ERR_FAIL_COND_V(voxel_data == nullptr, false);
@@ -1301,8 +1367,8 @@ bool VoxelTerrain::try_set_block_data(Vector3i position, std::shared_ptr<VoxelBu
 
 	if (refcount.get() == 0) {
 		// Actually, this block is not even in range. So we may ignore it.
-		// If we don't want this behavior, we could introduce a fake viewer that adds a reference to all blocks in this
-		// volume as long as it is enabled?
+		// If we don't want this behavior, we could introduce a fake viewer that adds a reference to all blocks in
+		// this volume as long as it is enabled?
 		return false;
 	}
 
@@ -1423,7 +1489,6 @@ void VoxelTerrain::apply_mesh_update(const VoxelServer::BlockMeshOutput &ob) {
 	}
 
 	Ref<ArrayMesh> mesh;
-	mesh.instantiate();
 
 	//need to put both blocky and smooth surfaces into one list
 	std::vector<Array> collidable_surfaces;
@@ -1442,17 +1507,33 @@ void VoxelTerrain::apply_mesh_update(const VoxelServer::BlockMeshOutput &ob) {
 
 		collidable_surfaces.push_back(surface);
 
+		if (mesh.is_null()) {
+			mesh.instantiate();
+		}
+
 		mesh->add_surface_from_arrays(
 				ob.surfaces.primitive_type, surface, Array(), Dictionary(), ob.surfaces.mesh_flags);
 		mesh->surface_set_material(surface_index, _materials[i]);
 		++surface_index;
 	}
 
-	if (is_mesh_empty(**mesh)) {
+	if (mesh.is_valid() && is_mesh_empty(**mesh)) {
 		mesh = Ref<Mesh>();
 		collidable_surfaces.clear();
 	}
 
+	if (_instancer != nullptr) {
+		if (mesh.is_null() && block != nullptr) {
+			// No surface anymore in this block
+			_instancer->on_mesh_block_exit(ob.position, ob.lod);
+		}
+		if (ob.surfaces.surfaces.size() > 0 && mesh.is_valid() && !block->has_mesh()) {
+			// TODO The mesh could come from an edited region!
+			// We would have to know if specific voxels got edited, or different from the generator
+			_instancer->on_mesh_block_enter(ob.position, ob.lod, ob.surfaces.surfaces[0]);
+		}
+	}
+
 	const bool gen_collisions = _generate_collisions && block->collision_viewers.get() > 0;
 
 	block->set_mesh(mesh, DirectMeshInstance::GIMode(get_gi_mode()));

terrain/fixed_lod/voxel_terrain.h

@@ -14,6 +14,7 @@
 namespace zylann::voxel {
 
 class VoxelTool;
+class VoxelInstancer;
 
 // Infinite paged terrain made of voxel blocks all with the same level of detail.
 // Voxels are polygonized around the viewer by distance in a large cubic space.
@@ -86,7 +87,7 @@ public:
 		return _data_map;
 	}
 
-	Ref<VoxelTool> get_voxel_tool();
+	Ref<VoxelTool> get_voxel_tool() override;
 
 	// Creates or overrides whatever block data there is at the given position.
 	// The use case is multiplayer, client-side.
@@ -129,6 +130,16 @@ public:
 		Vector3i position;
 	};
 
+	// Internal
+
+	void set_instancer(VoxelInstancer *instancer);
+	void get_meshed_block_positions(std::vector<Vector3i> &out_positions) const;
+	Array get_mesh_block_surface(Vector3i block_pos) const;
+
+	uint32_t get_volume_id() const override {
+		return _volume_id;
+	}
+
 protected:
 	void _notification(int p_what);
 
@@ -272,6 +283,8 @@ private:
 
 	GodotUniqueObjectPtr<VoxelDataBlockEnterInfo> _data_block_enter_info_obj;
 
+	VoxelInstancer *_instancer = nullptr;
+
 	Stats _stats;
 };
 

terrain/instancing/voxel_instancer.cpp

@@ -3,6 +3,7 @@
 #include "../../util/godot/funcs.h"
 #include "../../util/macros.h"
 #include "../../util/profiling.h"
+#include "../fixed_lod/voxel_terrain.h"
 #include "../variable_lod/voxel_lod_terrain.h"
 #include "voxel_instance_component.h"
 #include "voxel_instance_library_scene_item.h"
@@ -104,20 +105,41 @@ void VoxelInstancer::_notification(int p_what) {
 #endif
 			break;
 
-		case NOTIFICATION_PARENTED:
-			_parent = Object::cast_to<VoxelLodTerrain>(get_parent());
-			if (_parent != nullptr) {
-				_parent->set_instancer(this);
+		case NOTIFICATION_PARENTED: {
+			VoxelLodTerrain *vlt = Object::cast_to<VoxelLodTerrain>(get_parent());
+			if (vlt != nullptr) {
+				_parent = vlt;
+				_parent_data_block_size_po2 = vlt->get_data_block_size_pow2();
+				_parent_mesh_block_size_po2 = vlt->get_mesh_block_size_pow2();
+				_mesh_lod_distance = vlt->get_lod_distance();
+				vlt->set_instancer(this);
+			} else {
+				VoxelTerrain *vt = Object::cast_to<VoxelTerrain>(get_parent());
+				if (vt != nullptr) {
+					_parent = vt;
+					_parent_data_block_size_po2 = vt->get_data_block_size_pow2();
+					_parent_mesh_block_size_po2 = vt->get_mesh_block_size_pow2();
+					_mesh_lod_distance = vt->get_max_view_distance();
+					vt->set_instancer(this);
+				}
 			}
 			// TODO may want to reload all instances? Not sure if worth implementing that use case
-			break;
+		} break;
 
 		case NOTIFICATION_UNPARENTED:
 			clear_blocks();
 			if (_parent != nullptr) {
-				_parent->set_instancer(nullptr);
+				VoxelLodTerrain *vlt = Object::cast_to<VoxelLodTerrain>(_parent);
+				if (vlt != nullptr) {
+					vlt->set_instancer(nullptr);
+				} else {
+					VoxelTerrain *vt = Object::cast_to<VoxelTerrain>(get_parent());
+					if (vt != nullptr) {
+						vt->set_instancer(nullptr);
+					}
+				}
+				_parent = nullptr;
 			}
-			_parent = nullptr;
 			break;
 
 		case NOTIFICATION_TRANSFORM_CHANGED: {
@@ -130,7 +152,7 @@ void VoxelInstancer::_notification(int p_what) {
 			}
 
 			const Transform3D parent_transform = get_global_transform();
-			const int base_block_size_po2 = _parent->get_mesh_block_size_pow2();
+			const int base_block_size_po2 = _parent_mesh_block_size_po2;
 			//print_line(String("IP: {0}").format(varray(parent_transform.origin)));
 
 			for (auto it = _blocks.begin(); it != _blocks.end(); ++it) {
@@ -157,7 +179,7 @@ void VoxelInstancer::_notification(int p_what) {
 			break;
 
 		case NOTIFICATION_INTERNAL_PROCESS:
-			if (_parent != nullptr && _library.is_valid()) {
+			if (_parent != nullptr && _library.is_valid() && _mesh_lod_distance > 0.f) {
 				process_mesh_lods();
 			}
 #ifdef TOOLS_ENABLED
@@ -183,7 +205,7 @@ void VoxelInstancer::set_show_gizmos(bool enable) {
 void VoxelInstancer::process_gizmos() {
 	ERR_FAIL_COND(_parent == nullptr);
 	const Transform3D parent_transform = get_global_transform();
-	const int base_block_size_po2 = _parent->get_mesh_block_size_pow2();
+	const int base_block_size_po2 = _parent_mesh_block_size_po2;
 
 	_debug_renderer.begin();
 
@@ -246,13 +268,11 @@ void VoxelInstancer::process_mesh_lods() {
 	const Vector3 cam_pos_local = (gtrans.affine_inverse() * camera->get_global_transform()).origin;
 
 	ERR_FAIL_COND(_parent == nullptr);
-	const int block_size = _parent->get_mesh_block_size();
+	const int block_size = 1 << _parent_mesh_block_size_po2;
 
-	// Hardcoded LOD thresholds for now.
-	// Can't really use pixel density because view distances are controlled by the main surface LOD octree
 	{
-		const int block_region_extent = _parent->get_mesh_block_region_extent();
-
+		// Hardcoded LOD thresholds for now.
+		// Can't really use pixel density because view distances are controlled by the main surface LOD octree
 		FixedArray<float, 4> coeffs;
 		coeffs[0] = 0;
 		coeffs[1] = 0.1;
@@ -260,13 +280,15 @@ void VoxelInstancer::process_mesh_lods() {
 		coeffs[3] = 0.5;
 		const float hysteresis = 1.05;
 
+		const float max_distance = _mesh_lod_distance;
+
 		for (unsigned int lod_index = 0; lod_index < _lods.size(); ++lod_index) {
 			Lod &lod = _lods[lod_index];
-			const float max_distance = block_size * (block_region_extent << lod_index);
 
 			for (unsigned int j = 0; j < lod.mesh_lod_distances.size(); ++j) {
 				MeshLodDistances &mld = lod.mesh_lod_distances[j];
-				mld.exit_distance_squared = max_distance * max_distance * coeffs[j];
+				const float lod_max_distance = (1 << j) * max_distance;
+				mld.exit_distance_squared = lod_max_distance * lod_max_distance * coeffs[j];
 				mld.enter_distance_squared = hysteresis * mld.exit_distance_squared;
 			}
 		}
@@ -415,10 +437,19 @@ void VoxelInstancer::regenerate_layer(uint16_t layer_id, bool regenerate_blocks)
 
 	const Transform3D parent_transform = get_global_transform();
 
+	const VoxelLodTerrain *parent_vlt = Object::cast_to<VoxelLodTerrain>(_parent);
+	const VoxelTerrain *parent_vt = Object::cast_to<VoxelTerrain>(_parent);
+
 	if (regenerate_blocks) {
 		// Create blocks
 		std::vector<Vector3i> positions;
-		_parent->get_meshed_block_positions_at_lod(layer->lod_index, positions);
+
+		if (parent_vlt != nullptr) {
+			parent_vlt->get_meshed_block_positions_at_lod(layer->lod_index, positions);
+		} else if (parent_vt != nullptr) {
+			parent_vt->get_meshed_block_positions(positions);
+		}
+
 		for (unsigned int i = 0; i < positions.size(); ++i) {
 			const Vector3i pos = positions[i];
 
@@ -431,7 +462,7 @@ void VoxelInstancer::regenerate_layer(uint16_t layer_id, bool regenerate_blocks)
 		}
 	}
 
-	const int render_to_data_factor = _parent->get_mesh_block_size() / _parent->get_data_block_size();
+	const int render_to_data_factor = 1 << (_parent_mesh_block_size_po2 - _parent_mesh_block_size_po2);
 	ERR_FAIL_COND(render_to_data_factor <= 0 || render_to_data_factor > 2);
 
 	struct L {
@@ -500,9 +531,15 @@ void VoxelInstancer::regenerate_layer(uint16_t layer_id, bool regenerate_blocks)
 
 		_transform_cache.clear();
 
-		Array surface_arrays = _parent->get_mesh_block_surface(block->grid_position, lod_index);
+		Array surface_arrays;
+		if (parent_vlt != nullptr) {
+			surface_arrays = parent_vlt->get_mesh_block_surface(block->grid_position, lod_index);
+		} else if (parent_vt != nullptr) {
+			surface_arrays = parent_vt->get_mesh_block_surface(block->grid_position);
+		}
 
-		const int lod_block_size = _parent->get_mesh_block_size() << lod_index;
+		const int mesh_block_size = 1 << _parent_mesh_block_size_po2;
+		const int lod_block_size = mesh_block_size << lod_index;
 		const Transform3D block_local_transform(Basis(), Vector3(block->grid_position * lod_block_size));
 		const Transform3D block_transform = parent_transform * block_local_transform;
 
@@ -512,7 +549,7 @@ void VoxelInstancer::regenerate_layer(uint16_t layer_id, bool regenerate_blocks)
 
 		if (render_to_data_factor == 2 && octant_mask != 0xff) {
 			// Complete transforms with edited ones
-			L::extract_octant_transforms(*block, _transform_cache, ~octant_mask, _parent->get_mesh_block_size());
+			L::extract_octant_transforms(*block, _transform_cache, ~octant_mask, mesh_block_size);
 			// TODO What if these blocks had loaded data which wasn't yet uploaded for render?
 			// We may setup a local transform list as well since it's expensive to get it from VisualServer
 		}
@@ -553,7 +590,7 @@ void VoxelInstancer::update_layer_scenes(int layer_id) {
 	ERR_FAIL_COND(item_base.is_null());
 	VoxelInstanceLibrarySceneItem *item = Object::cast_to<VoxelInstanceLibrarySceneItem>(*item_base);
 	ERR_FAIL_COND(item == nullptr);
-	const int data_block_size_po2 = _parent->get_data_block_size_pow2();
+	const int data_block_size_po2 = _parent_data_block_size_po2;
 
 	for (unsigned int block_index = 0; block_index < _blocks.size(); ++block_index) {
 		Block *block = _blocks[block_index];
@@ -728,7 +765,8 @@ void VoxelInstancer::on_mesh_block_exit(Vector3i render_grid_position, unsigned
 	Lod &lod = _lods[lod_index];
 
 	// Remove data blocks
-	const int render_to_data_factor = _parent->get_mesh_block_size() / _parent->get_data_block_size();
+	const int render_to_data_factor = 1 << (_parent_mesh_block_size_po2 - _parent_data_block_size_po2);
+	ERR_FAIL_COND(render_to_data_factor <= 0 || render_to_data_factor > 2);
 	const Vector3i data_min_pos = render_grid_position * render_to_data_factor;
 	const Vector3i data_max_pos = data_min_pos + Vector3iUtil::create(render_to_data_factor);
 	Vector3i data_grid_pos;
@@ -878,7 +916,7 @@ void VoxelInstancer::update_block_from_transforms(int block_index, Span<const Tr
 		if (collision_shapes.size() > 0) {
 			ZN_PROFILE_SCOPE_NAMED("Update multimesh bodies");
 
-			const int data_block_size_po2 = _parent->get_data_block_size_pow2();
+			const int data_block_size_po2 = _parent_data_block_size_po2;
 
 			// Add new bodies
 			for (unsigned int instance_index = 0; instance_index < transforms.size(); ++instance_index) {
@@ -930,7 +968,7 @@ void VoxelInstancer::update_block_from_transforms(int block_index, Span<const Tr
 		ZN_PROFILE_SCOPE_NAMED("Update scene instances");
 		ERR_FAIL_COND(scene_item->get_scene().is_null());
 
-		const int data_block_size_po2 = _parent->get_data_block_size_pow2();
+		const int data_block_size_po2 = _parent_data_block_size_po2;
 
 		// Add new instances
 		for (unsigned int instance_index = 0; instance_index < transforms.size(); ++instance_index) {
@@ -989,15 +1027,16 @@ void VoxelInstancer::create_render_blocks(Vector3i render_grid_position, int lod
 	ERR_FAIL_COND(world_ref.is_null());
 	World3D *world = *world_ref;
 
-	const int lod_block_size = _parent->get_mesh_block_size() << lod_index;
+	const int mesh_block_size = (1 << _parent_mesh_block_size_po2);
+	const int lod_block_size = mesh_block_size << lod_index;
 	const Transform3D block_local_transform = Transform3D(Basis(), render_grid_position * lod_block_size);
 	const Transform3D block_transform = parent_transform * block_local_transform;
 
-	const int render_to_data_factor = _parent->get_mesh_block_size() / _parent->get_data_block_size();
+	const int render_to_data_factor = mesh_block_size / (1 << _parent_data_block_size_po2);
 	const Vector3i data_min_pos = render_grid_position * render_to_data_factor;
 	const Vector3i data_max_pos = data_min_pos + Vector3iUtil::create(render_to_data_factor);
 
-	const int lod_render_block_size = _parent->get_mesh_block_size() << lod_index;
+	const int lod_render_block_size = mesh_block_size << lod_index;
 
 	for (auto layer_it = lod.layers.begin(); layer_it != lod.layers.end(); ++layer_it) {
 		const int layer_id = *layer_it;
@@ -1083,19 +1122,20 @@ void VoxelInstancer::create_render_blocks(Vector3i render_grid_position, int lod
 void VoxelInstancer::save_block(Vector3i data_grid_pos, int lod_index) const {
 	ZN_PROFILE_SCOPE();
 	ERR_FAIL_COND(_library.is_null());
+	ERR_FAIL_COND(_parent == nullptr);
 
 	ZN_PRINT_VERBOSE(format("Requesting save of instance block {} lod {}", data_grid_pos, lod_index));
 
 	const Lod &lod = _lods[lod_index];
 
 	std::unique_ptr<InstanceBlockData> data = std::make_unique<InstanceBlockData>();
-	const int data_block_size = _parent->get_data_block_size() << lod_index;
+	const int data_block_size = (1 << _parent_data_block_size_po2) << lod_index;
 	data->position_range = data_block_size;
 
-	const int render_to_data_factor = _parent->get_mesh_block_size() / _parent->get_data_block_size();
+	const int render_to_data_factor = (1 << _parent_mesh_block_size_po2) / (1 << _parent_data_block_size_po2);
 	ERR_FAIL_COND_MSG(render_to_data_factor < 1 || render_to_data_factor > 2, "Unsupported block size");
 
-	const int half_render_block_size = _parent->get_mesh_block_size() / 2;
+	const int half_render_block_size = (1 << _parent_mesh_block_size_po2) / 2;
 	const Vector3i render_block_pos = Vector3iUtil::floordiv(data_grid_pos, render_to_data_factor);
 
 	const int octant_index = (data_grid_pos.x & 1) | ((data_grid_pos.y & 1) << 1) | ((data_grid_pos.z & 1) << 1);
@@ -1363,15 +1403,15 @@ void VoxelInstancer::remove_floating_scene_instances(Block &block, const Transfo
 void VoxelInstancer::on_area_edited(Box3i p_voxel_box) {
 	ZN_PROFILE_SCOPE();
 	ERR_FAIL_COND(_parent == nullptr);
-	const int render_block_size = _parent->get_mesh_block_size();
-	const int data_block_size = _parent->get_data_block_size();
+	const int render_block_size = 1 << _parent_mesh_block_size_po2;
+	const int data_block_size = 1 << _parent_data_block_size_po2;
 
 	Ref<VoxelTool> voxel_tool = _parent->get_voxel_tool();
 	ERR_FAIL_COND(voxel_tool.is_null());
 	voxel_tool->set_channel(VoxelBufferInternal::CHANNEL_SDF);
 
 	const Transform3D parent_transform = get_global_transform();
-	const int base_block_size_po2 = _parent->get_mesh_block_size_pow2();
+	const int base_block_size_po2 = 1 << _parent_mesh_block_size_po2;
 
 	for (unsigned int lod_index = 0; lod_index < _lods.size(); ++lod_index) {
 		Lod &lod = _lods[lod_index];
@@ -1492,6 +1532,18 @@ void VoxelInstancer::on_scene_instance_modified(Vector3i data_block_position, un
 	lod.modified_blocks.set(data_block_position, true);
 }
 
+void VoxelInstancer::set_mesh_block_size_po2(unsigned int p_mesh_block_size_po2) {
+	_parent_mesh_block_size_po2 = p_mesh_block_size_po2;
+}
+
+void VoxelInstancer::set_data_block_size_po2(unsigned int p_data_block_size_po2) {
+	_parent_data_block_size_po2 = p_data_block_size_po2;
+}
+
+void VoxelInstancer::set_mesh_lod_distance(float p_lod_distance) {
+	_mesh_lod_distance = p_lod_distance;
+}
+
 int VoxelInstancer::debug_get_block_count() const {
 	return _blocks.size();
 }
@@ -1540,7 +1592,7 @@ void VoxelInstancer::debug_dump_as_scene(String fpath) const {
 
 Node *VoxelInstancer::debug_dump_as_nodes() const {
 	ERR_FAIL_COND_V(_parent == nullptr, nullptr);
-	const unsigned int mesh_block_size = _parent->get_mesh_block_size();
+	const unsigned int mesh_block_size = 1 << _parent_mesh_block_size_po2;
 
 	Node3D *root = memnew(Node3D);
 	root->set_transform(get_transform());

terrain/instancing/voxel_instancer.h

@@ -1,6 +1,7 @@
 #ifndef VOXEL_INSTANCER_H
 #define VOXEL_INSTANCER_H
 
+#include "../../constants/voxel_constants.h"
 #include "../../streams/instance_data.h"
 #include "../../util/fixed_array.h"
 #include "../../util/godot/direct_multimesh_instance.h"
@@ -24,7 +25,7 @@ class PhysicsBody3D;
 
 namespace zylann::voxel {
 
-class VoxelLodTerrain;
+class VoxelNode;
 class VoxelInstancerRigidBody;
 class VoxelInstanceComponent;
 class VoxelInstanceLibrarySceneItem;
@@ -73,6 +74,12 @@ public:
 			Vector3i data_block_position, unsigned int render_block_index, unsigned int instance_index);
 	void on_scene_instance_modified(Vector3i data_block_position, unsigned int render_block_index);
 
+	// Internal properties
+
+	void set_mesh_block_size_po2(unsigned int p_mesh_block_size_po2);
+	void set_data_block_size_po2(unsigned int p_data_block_size_po2);
+	void set_mesh_lod_distance(float p_lod_distance);
+
 	// Debug
 
 	int debug_get_block_count() const;
@@ -203,7 +210,10 @@ private:
 
 	std::vector<Transform3D> _transform_cache;
 
-	VoxelLodTerrain *_parent;
+	VoxelNode *_parent = nullptr;
+	unsigned int _parent_data_block_size_po2 = constants::DEFAULT_BLOCK_SIZE_PO2;
+	unsigned int _parent_mesh_block_size_po2 = constants::DEFAULT_BLOCK_SIZE_PO2;
+	float _mesh_lod_distance = 0.f;
 
 #ifdef TOOLS_ENABLED
 	DebugRenderer _debug_renderer;

terrain/variable_lod/voxel_lod_terrain.cpp

@@ -420,6 +420,11 @@ void VoxelLodTerrain::set_mesh_block_size(unsigned int mesh_block_size) {
 		lod.last_view_distance_mesh_blocks = 0;
 	}
 
+	// Doing this after because `on_mesh_block_exit` may use the old size
+	if (_instancer != nullptr) {
+		_instancer->set_mesh_block_size_po2(mesh_block_size);
+	}
+
 	// Reset LOD octrees
 	LodOctree::NoDestroyAction nda;
 	for (Map<Vector3i, VoxelLodTerrainUpdateData::OctreeItem>::Element *E = state.lod_octrees.front(); E;
@@ -766,10 +771,15 @@ void VoxelLodTerrain::set_lod_distance(float p_lod_distance) {
 
 	// Distance must be greater than a threshold,
 	// otherwise lods will decimate too fast and it will look messy
-	_update_data->settings.lod_distance =
+	const float lod_distance =
 			math::clamp(p_lod_distance, constants::MINIMUM_LOD_DISTANCE, constants::MAXIMUM_LOD_DISTANCE);
+	_update_data->settings.lod_distance = lod_distance;
 	_update_data->state.force_update_octrees_next_update = true;
 	VoxelServer::get_singleton().set_volume_octree_lod_distance(_volume_id, get_lod_distance());
+
+	if (_instancer != nullptr) {
+		_instancer->set_mesh_lod_distance(lod_distance);
+	}
 }
 
 float VoxelLodTerrain::get_lod_distance() const {

terrain/variable_lod/voxel_lod_terrain.h

@@ -232,7 +232,7 @@ public:
 	// Internal
 
 	void set_instancer(VoxelInstancer *instancer);
-	uint32_t get_volume_id() const {
+	uint32_t get_volume_id() const override {
 		return _volume_id;
 	}
 

terrain/voxel_node.cpp

@@ -1,4 +1,5 @@
 #include "voxel_node.h"
+#include "../edition/voxel_tool.h"
 #include "../generators/voxel_generator.h"
 #include "../meshers/voxel_mesher.h"
 #include "../streams/voxel_stream.h"
@@ -40,6 +41,16 @@ void VoxelNode::remesh_all_blocks() {
 	// Not implemented
 }
 
+uint32_t VoxelNode::get_volume_id() const {
+	CRASH_NOW_MSG("Not implemented");
+	return 0;
+}
+
+Ref<VoxelTool> VoxelNode::get_voxel_tool() {
+	CRASH_NOW_MSG("Not implemented");
+	return Ref<VoxelTool>();
+}
+
 #ifdef TOOLS_ENABLED
 
 TypedArray<String> VoxelNode::get_configuration_warnings() const {

terrain/voxel_node.h

@@ -9,6 +9,8 @@
 
 namespace zylann::voxel {
 
+class VoxelTool;
+
 // Base class for voxel volumes
 class VoxelNode : public Node3D {
 	GDCLASS(VoxelNode, Node3D)
@@ -35,6 +37,10 @@ public:
 	virtual void restart_stream();
 	virtual void remesh_all_blocks();
 
+	virtual uint32_t get_volume_id() const;
+
+	virtual Ref<VoxelTool> get_voxel_tool();
+
 #ifdef TOOLS_ENABLED
 	virtual TypedArray<String> get_configuration_warnings() const override;
 #endif