diff --git a/server/gameserver/bullet.cc b/server/gameserver/bullet.cc
index a5f6009..47477bc 100644
--- a/server/gameserver/bullet.cc
+++ b/server/gameserver/bullet.cc
@@ -4,6 +4,7 @@
 #include "metamgr.h"
 #include "movement.h"
 #include "room.h"
+#include "collider.h"
 
 Bullet::Bullet():Entity()
 {
@@ -19,6 +20,7 @@ Bullet::~Bullet()
 
 void Bullet::Initialize()
 {
+    RecalcSelfCollider();
 }
 
 void Bullet::Update(int delta_time)
@@ -31,3 +33,13 @@ void Bullet::Update(int delta_time)
         room->AddDeletedObject(objects[0]->entity_uniid);
     }
 }
+
+void Bullet::RecalcSelfCollider()
+{
+    if (!self_collider_) {
+        self_collider_ = new CircleCollider();
+        colliders.push_back(self_collider_);
+    }
+    self_collider_->pos = Vector2D();
+    self_collider_->rad = meta->i->bullet_rad();
+}
diff --git a/server/gameserver/bullet.h b/server/gameserver/bullet.h
index 291adea..479f235 100644
--- a/server/gameserver/bullet.h
+++ b/server/gameserver/bullet.h
@@ -9,6 +9,7 @@ namespace MetaData
 }
 
 class Human;
+class CircleCollider;
 class Bullet : public Entity
 {
  public:
@@ -22,4 +23,9 @@ class Bullet : public Entity
     virtual ~Bullet() override;
     virtual void Initialize() override;
     virtual void Update(int delta_time) override;
+    void RecalcSelfCollider();
+
+private:
+    CircleCollider* self_collider_ = nullptr;
+
 };
diff --git a/server/gameserver/entity.cc b/server/gameserver/entity.cc
index a7cae5c..4c49a06 100644
--- a/server/gameserver/entity.cc
+++ b/server/gameserver/entity.cc
@@ -30,5 +30,12 @@ Entity::~Entity()
 
 bool Entity::TestCollision(Entity* b)
 {
-    return false;
+    for (auto& a_collider : b->colliders) {
+        for (auto& b_collider : b->colliders) {
+            if (a_collider->Intersect(b_collider)) {
+                return false;
+            }
+        }
+    }
+    return true;
 }
diff --git a/server/gameserver/human.cc b/server/gameserver/human.cc
index 597ea8f..6444df0 100644
--- a/server/gameserver/human.cc
+++ b/server/gameserver/human.cc
@@ -6,6 +6,7 @@
 #include "metamgr.h"
 #include "room.h"
 #include "bullet.h"
+#include "collider.h"
 
 Human::Human()
 {
@@ -26,6 +27,7 @@ void Human::Initialize()
     helmet_meta = MetaMgr::Instance()->GetEquip(helmet);
     chest_meta = MetaMgr::Instance()->GetEquip(chest);
     weapon_meta = MetaMgr::Instance()->GetEquip(weapon);
+    RecalcSelfCollider();
 }
 
 float Human::GetSpeed()
@@ -101,3 +103,13 @@ void Human::Shot(Vector2D& target_dir)
         room->AddBullet(bullet);
     }
 }
+
+void Human::RecalcSelfCollider()
+{
+    if (!self_collider_) {
+        self_collider_ = new CircleCollider();
+        colliders.push_back(self_collider_);
+    }
+    self_collider_->pos = Vector2D();
+    self_collider_->rad = meta->i->radius();
+}
diff --git a/server/gameserver/human.h b/server/gameserver/human.h
index e038a82..723e733 100644
--- a/server/gameserver/human.h
+++ b/server/gameserver/human.h
@@ -15,6 +15,7 @@ struct HumanFrameData
     ::google::protobuf::RepeatedPtrField<::cs::MFShot> shots;
 };
 
+class CircleCollider;
 class Human : public Entity
 {
  public:
@@ -57,5 +58,9 @@ class Human : public Entity
     virtual void FillMFObjectPart(cs::MFObjectPart* part_data) override;
     virtual void FillMFObjectFull(cs::MFObjectFull* full_data) override;
     void Shot(Vector2D& target_dir);
+    void RecalcSelfCollider();
+
+private:
+    CircleCollider* self_collider_ = nullptr;
 
 };
diff --git a/third_party/tools b/third_party/tools
index 0fe613a..23026cb 160000
--- a/third_party/tools
+++ b/third_party/tools
@@ -1 +1 @@
-Subproject commit 0fe613a85023d94103a013cadcc4927004aab8b4
+Subproject commit 23026cb4e2ec630f6d421f742b65de6752a57b9d