diff --git a/src/constants.hpp b/src/constants.hpp
index 15b3e732..b1ae11d4 100644
--- a/src/constants.hpp
+++ b/src/constants.hpp
@@ -16,6 +16,12 @@ inline constexpr bool ENGINE_DEBUG_BUILD = true;
 
 inline const std::string ENGINE_VERSION_STRING = "0.23";
 
+/// @brief world regions format version
+inline constexpr uint REGION_FORMAT_VERSION = 2;
+
+/// @brief max simultaneously open world region files
+inline constexpr uint MAX_OPEN_REGION_FILES = 32;
+
 inline constexpr blockid_t BLOCK_AIR = 0;
 inline constexpr itemid_t ITEM_EMPTY = 0;
 inline constexpr entityid_t ENTITY_NONE = 0;
@@ -40,6 +46,7 @@ inline constexpr itemid_t ITEM_VOID = std::numeric_limits<itemid_t>::max();
 /// @brief max number of block definitions possible
 inline constexpr blockid_t MAX_BLOCKS = BLOCK_VOID;
 
+/// @brief calculates a 1D array index from 3D array indices
 inline constexpr uint vox_index(uint x, uint y, uint z, uint w=CHUNK_W, uint d=CHUNK_D) {
     return (y * d + z) * w + x;
 }
diff --git a/src/files/WorldRegions.cpp b/src/files/WorldRegions.cpp
index 07400895..cd0955c1 100644
--- a/src/files/WorldRegions.cpp
+++ b/src/files/WorldRegions.cpp
@@ -51,8 +51,8 @@ uint WorldRegion::getChunkDataSize(uint x, uint z) {
 }
 
 WorldRegions::WorldRegions(const fs::path& directory) : directory(directory) {
-    for (size_t i = 0; i < sizeof(layers) / sizeof(RegionsLayer); i++) {
-        layers[i].layer = i;
+    for (size_t i = 0; i < REGION_LAYERS_COUNT; i++) {
+        layers[i].layer = static_cast<RegionLayerIndex>(i);
     }
     auto& voxels = layers[REGION_LAYER_VOXELS];
     voxels.folder = directory / fs::path("regions");
@@ -83,7 +83,7 @@ void RegionsLayer::writeAll() {
 void WorldRegions::put(
     int x,
     int z,
-    int layerid,
+    RegionLayerIndex layerid,
     std::unique_ptr<ubyte[]> data,
     size_t size
 ) {
diff --git a/src/files/WorldRegions.hpp b/src/files/WorldRegions.hpp
index df77fdb2..eb2e803a 100644
--- a/src/files/WorldRegions.hpp
+++ b/src/files/WorldRegions.hpp
@@ -8,6 +8,7 @@
 #include <mutex>
 #include <unordered_map>
 
+#include "constants.hpp"
 #include "typedefs.hpp"
 #include "data/dynamic_fwd.hpp"
 #include "util/BufferPool.hpp"
@@ -23,16 +24,18 @@ namespace fs = std::filesystem;
 
 inline constexpr uint REGION_HEADER_SIZE = 10;
 
-inline constexpr uint REGION_LAYER_VOXELS = 0;
-inline constexpr uint REGION_LAYER_LIGHTS = 1;
-inline constexpr uint REGION_LAYER_INVENTORIES = 2;
-inline constexpr uint REGION_LAYER_ENTITIES = 3;
+enum RegionLayerIndex : uint {
+    REGION_LAYER_VOXELS = 0,
+    REGION_LAYER_LIGHTS,
+    REGION_LAYER_INVENTORIES,
+    REGION_LAYER_ENTITIES,
+    
+    REGION_LAYERS_COUNT
+};
 
 inline constexpr uint REGION_SIZE_BIT = 5;
 inline constexpr uint REGION_SIZE = (1 << (REGION_SIZE_BIT));
 inline constexpr uint REGION_CHUNKS_COUNT = ((REGION_SIZE) * (REGION_SIZE));
-inline constexpr uint REGION_FORMAT_VERSION = 2;
-inline constexpr uint MAX_OPEN_REGION_FILES = 32;
 
 class illegal_region_format : public std::runtime_error {
 public:
@@ -122,7 +125,7 @@ inline void calc_reg_coords(
 
 struct RegionsLayer {
     /// @brief Layer index
-    int layer;
+    RegionLayerIndex layer;
     
     /// @brief Regions layer folder
     fs::path folder;
@@ -180,7 +183,7 @@ class WorldRegions {
     /// @brief World directory
     fs::path directory;
 
-    RegionsLayer layers[4] {};
+    RegionsLayer layers[REGION_LAYERS_COUNT] {};
 public:
     bool generatorTestMode = false;
     bool doWriteLights = true;
@@ -201,7 +204,7 @@ public:
     void put(
         int x,
         int z,
-        int layer,
+        RegionLayerIndex layer,
         std::unique_ptr<ubyte[]> data,
         size_t size
     );