diff --git a/source/engine/graphics/back/buffers/DynamicBuffer.hpp b/source/engine/graphics/back/buffers/DynamicBuffer.hpp
index 1cf3573b719ae75776f8dda6fd7f4b2818f00b0b..aea44f2d9207bd104ec89a2141babcf7352d2764 100644
--- a/source/engine/graphics/back/buffers/DynamicBuffer.hpp
+++ b/source/engine/graphics/back/buffers/DynamicBuffer.hpp
@@ -50,7 +50,7 @@ namespace megu {
             T at(size_t index) const;
 
             std::vector<T> extract() const;
-            std::vector<T> extract(size_t from,size_t to) const;
+            std::vector<T> extract(size_t from, size_t to) const;
 
             T operator[](size_t index) const;
 
diff --git a/source/engine/graphics/back/buffers/ElementBuffer.cpp b/source/engine/graphics/back/buffers/ElementBuffer.cpp
index 07b4e4ec5e2a6bb4ce30cd61be99c24cd7d2b39f..a3fe92993dcd3db52185c7b314b65a81f63ea7c8 100644
--- a/source/engine/graphics/back/buffers/ElementBuffer.cpp
+++ b/source/engine/graphics/back/buffers/ElementBuffer.cpp
@@ -70,6 +70,10 @@ namespace megu {
         return this->_id <= ebo._id;
     }
 
+    bool ElementBuffer::operator()(const ElementBuffer & ebo) const {
+        return *this < ebo;
+    }
+
     std::strong_ordering ElementBuffer::operator<=>(const ElementBuffer & ebo) const {
         return this->_id <=> ebo._id; 
     }
diff --git a/source/engine/graphics/back/buffers/ElementBuffer.hpp b/source/engine/graphics/back/buffers/ElementBuffer.hpp
index cff85434716f41eddbe850b66bf7eb0b4b2f3252..e873b580ec5b67a4fa37e52dd77cd0a40e0c3d68 100644
--- a/source/engine/graphics/back/buffers/ElementBuffer.hpp
+++ b/source/engine/graphics/back/buffers/ElementBuffer.hpp
@@ -26,6 +26,7 @@ namespace megu {
             inline bool operator!=(const ElementBuffer &) const;
             inline bool operator<=(const ElementBuffer &) const;
             inline bool operator>=(const ElementBuffer &) const;
+            inline bool operator()(const ElementBuffer &) const;
 
             inline bool operator<(const ElementBuffer &) const;
             inline bool operator>(const ElementBuffer &) const;
diff --git a/source/engine/graphics/back/buffers/VertexArray.cpp b/source/engine/graphics/back/buffers/VertexArray.cpp
index ad2d67c556d534c00c85d73a8eae8456f0a9d27a..da6f9fe305f8dbad8a38a0630c4c2811e84f4fa2 100644
--- a/source/engine/graphics/back/buffers/VertexArray.cpp
+++ b/source/engine/graphics/back/buffers/VertexArray.cpp
@@ -45,6 +45,10 @@ namespace megu {
         return this->_vao >= vao._vao;
     }
 
+    bool VertexArray::operator()(const VertexArray & vao) const {
+        return *this > vao;
+    }
+
     bool VertexArray::operator<(const VertexArray & vao) const {
         return this->_vao < vao._vao;
     }
diff --git a/source/engine/graphics/back/buffers/VertexArray.hpp b/source/engine/graphics/back/buffers/VertexArray.hpp
index 8e5ee67f1a4d9d43649695760f3c778270db0830..4c8fdc2571a35ee00ff95f45776aa52b9ec62ab2 100644
--- a/source/engine/graphics/back/buffers/VertexArray.hpp
+++ b/source/engine/graphics/back/buffers/VertexArray.hpp
@@ -21,6 +21,7 @@ namespace megu {
             bool operator!=(const VertexArray &) const;
             bool operator<=(const VertexArray &) const;
             bool operator>=(const VertexArray &) const;
+            bool operator()(const VertexArray &) const;
 
             bool operator<(const VertexArray &) const;
             bool operator>(const VertexArray &) const;
diff --git a/source/engine/graphics/back/buffers/VerticeBuffer.cpp b/source/engine/graphics/back/buffers/VerticeBuffer.cpp
index 98e2c4d06c568802d40f8df5cc432d4b6980a2d2..2bcee15e52d8c3e1395bb6dfc856fd71d184312e 100644
--- a/source/engine/graphics/back/buffers/VerticeBuffer.cpp
+++ b/source/engine/graphics/back/buffers/VerticeBuffer.cpp
@@ -90,6 +90,10 @@ namespace megu {
         return this->_id <= vbo._id;
     }
 
+    bool VerticeBuffer::operator()(const VerticeBuffer & vbo) const {
+        return *this < vbo;
+    }
+
     std::strong_ordering VerticeBuffer::operator<=>(const VerticeBuffer & vbo) const {
         return this->_id <=> vbo._id; 
     }
diff --git a/source/engine/graphics/back/buffers/VerticeBuffer.hpp b/source/engine/graphics/back/buffers/VerticeBuffer.hpp
index 7c440037ff2514d44bebd2ed54e89f7e87c8056f..27411dfe9e1db0d4bcc46b83f9e3e31e412ca9ef 100644
--- a/source/engine/graphics/back/buffers/VerticeBuffer.hpp
+++ b/source/engine/graphics/back/buffers/VerticeBuffer.hpp
@@ -35,6 +35,7 @@ namespace megu {
             bool operator!=(const VerticeBuffer &) const;
             bool operator<=(const VerticeBuffer &) const;
             bool operator>=(const VerticeBuffer &) const;
+            bool operator()(const VerticeBuffer &) const;
             
             bool operator<(const VerticeBuffer &) const;
             bool operator>(const VerticeBuffer &) const;