diff --git a/server/gameserver/mapservice.cc b/server/gameserver/mapservice.cc
index 4db4d26..945b8b6 100644
--- a/server/gameserver/mapservice.cc
+++ b/server/gameserver/mapservice.cc
@@ -90,10 +90,17 @@ void MapService::AddCollider(ColliderComponent* collider)
             float min_y = (collider->owner->pos + aabb._min).y - 2;
             float max_x = (collider->owner->pos + aabb._max).x + 2;
             float max_y = (collider->owner->pos + aabb._max).y + 2;
+            #if 1
+            int min_grid_x = floor(min_x / cell_width_);
+            int min_grid_y = floor(min_y / cell_width_);
+            int max_grid_x = ceil(max_x / cell_width_);
+            int max_grid_y = ceil(max_y / cell_width_);
+            #else
             int min_grid_x = ceil(min_x / cell_width_) - 1;
             int min_grid_y = ceil(min_y / cell_width_) - 1;
             int max_grid_x = ceil(max_x / cell_width_) - 1;
             int max_grid_y = ceil(max_y / cell_width_) - 1;
+            #endif
             if (min_grid_x < 0 || max_grid_x >= map_width_) {
                 abort();
             }
@@ -148,17 +155,6 @@ void MapService::RemoveCollider(ColliderComponent* collider)
     }
 }
 
-bool MapService::Walkable(float world_x, float world_y)
-{
-    int grid_id = GetGridId(world_x, world_y);
-    if (grid_id < 0 || grid_id >= max_grid_id_) {
-        return false;
-    }
-    list_head& node = map_cells_[grid_id];
-    return (node.next == nullptr && node.prev == nullptr) ||
-        list_empty(&node);
-}
-
 void MapService::GetColliders(float world_x, float world_y, std::set<ColliderComponent*>& colliders)
 {
     int center_grid_id = GetGridId(world_x, world_y);
diff --git a/server/gameserver/mapservice.h b/server/gameserver/mapservice.h
index dcf71f0..6cf8cd8 100644
--- a/server/gameserver/mapservice.h
+++ b/server/gameserver/mapservice.h
@@ -20,7 +20,6 @@ class MapService
 
     void AddCollider(ColliderComponent* collider);
     void RemoveCollider(ColliderComponent* collider);
-    bool Walkable(float world_x, float world_y);
     void GetColliders(float world_x, float world_y, std::set<ColliderComponent*>& colliders);
 
  private: