diff --git a/include/m_collision_bg.h b/include/m_collision_bg.h
index 6082cb49..af5db379 100644
--- a/include/m_collision_bg.h
+++ b/include/m_collision_bg.h
@@ -174,7 +174,7 @@ extern f32 mCoBG_GetBgY_AngleS_FromWpos(s_xyz* angle_to_ground, xyz_t wpos, f32
 extern f32 mCoBG_GetShadowBgY_AngleS_FromWpos(f32, s_xyz*, xyz_t);
 extern int mCoBG_CheckWaterAttribute_OutOfSea(u32 attribute);
 extern int mCoBG_CheckHole_OrgAttr(u32 attribute);
-extern f32 mCoBG_GetBgY_OnlyCenter_FromWpos(f32 dist, xyz_t* wpos);
+extern f32 mCoBG_GetBgY_OnlyCenter_FromWpos(xyz_t wpos, f32 dist);
 extern f32 mCoBG_GetBgY_OnlyCenter_FromWpos2(xyz_t wpos, f32 foot_dist);
 extern int mCoBG_Attribute2CheckPlant(u32 attribute, const xyz_t* wpos);
 extern void mCoBG_BgCheckControll(xyz_t* reverse_pos, ACTOR* actor, f32 check_range, f32 offset_y, s16 wall_attr_check, s16 no_reverse, s16 check_type);
diff --git a/rel/ef_room_sunshine.c b/rel/ef_room_sunshine.c
index 80084ceb..a3df47d7 100644
--- a/rel/ef_room_sunshine.c
+++ b/rel/ef_room_sunshine.c
@@ -49,9 +49,7 @@ void Ef_Room_Sunshine_actor_ct(ACTOR* actor, GAME* game){
         sunshine->actor_class.world.position.x -= 1.0f;
     }
 
-    pos = sunshine->actor_class.world.position;
-    
-    sunshine->actor_class.world.position.y = mCoBG_GetBgY_OnlyCenter_FromWpos(0.0f, &pos);
+    sunshine->actor_class.world.position.y = mCoBG_GetBgY_OnlyCenter_FromWpos(sunshine->actor_class.world.position, 0.0f);
 
     sunshine->actor_class.scale.x = 1.0f;
     sunshine->actor_class.scale.y = 1.0f;
@@ -64,15 +62,13 @@ void Ef_Room_Sunshine_actor_ct(ACTOR* actor, GAME* game){
             sunshine->actor_class.mv_proc = Ef_Room_SunshineL_actor_move;
             sunshine->actor_class.dw_proc = Ef_Room_SunshineL_actor_draw;
             sunshine->actor_class.world.position.x += 5.0f;
-            pos2 = sunshine->actor_class.world.position;
-            sunshine->actor_class.world.position.y = 1.0f + mCoBG_GetBgY_OnlyCenter_FromWpos(0.0f, &pos2);
+            sunshine->actor_class.world.position.y = 1.0f + mCoBG_GetBgY_OnlyCenter_FromWpos(sunshine->actor_class.world.position, 0.0f);
             sunshine->actor_class.world.position.x -= 6.0f;
         break;
 
         case 3:
             sunshine->actor_class.world.position.x -= 5.0f;
-            pos3 = sunshine->actor_class.world.position;
-            sunshine->actor_class.world.position.y = 1.0f + mCoBG_GetBgY_OnlyCenter_FromWpos(0.0f, &pos3);
+            sunshine->actor_class.world.position.y = 1.0f + mCoBG_GetBgY_OnlyCenter_FromWpos(sunshine->actor_class.world.position, 0.0f);
             sunshine->actor_class.world.position.x += 6.0f;
         break;
     }
diff --git a/rel/ef_room_sunshine_minsect.c b/rel/ef_room_sunshine_minsect.c
index b254a02f..879ef833 100644
--- a/rel/ef_room_sunshine_minsect.c
+++ b/rel/ef_room_sunshine_minsect.c
@@ -47,10 +47,8 @@ void Ef_Room_Sunshine_Minsect_actor_ct(ACTOR* actor, GAME* game){
     else{
         minsect->ef_sunshine_class.actor_class.world.position.x -= 1.0f;
     }
-
-    pos = minsect->ef_sunshine_class.actor_class.world.position;
     
-    minsect->ef_sunshine_class.actor_class.world.position.y = mCoBG_GetBgY_OnlyCenter_FromWpos(0.0f, &pos);
+    minsect->ef_sunshine_class.actor_class.world.position.y = mCoBG_GetBgY_OnlyCenter_FromWpos(minsect->ef_sunshine_class.actor_class.world.position, 0.0f);
 
     minsect->ef_sunshine_class.actor_class.scale.x = 0.01f;
     minsect->ef_sunshine_class.actor_class.scale.y = 0.01f;
diff --git a/rel/ef_room_sunshine_museum.c b/rel/ef_room_sunshine_museum.c
index 9d4715ed..3565934c 100644
--- a/rel/ef_room_sunshine_museum.c
+++ b/rel/ef_room_sunshine_museum.c
@@ -46,9 +46,7 @@ void Ef_Room_Sunshine_Museum_actor_ct(ACTOR* actor, GAME* game){
         museum->ef_sunshine_class.actor_class.world.position.x -= 1.0f;
     }
 
-    pos = museum->ef_sunshine_class.actor_class.world.position;
-    
-    museum->ef_sunshine_class.actor_class.world.position.y = mCoBG_GetBgY_OnlyCenter_FromWpos(0.0f, &pos);
+    museum->ef_sunshine_class.actor_class.world.position.y = mCoBG_GetBgY_OnlyCenter_FromWpos(museum->ef_sunshine_class.actor_class.world.position, 0.0f);
 
     museum->ef_sunshine_class.actor_class.scale.x = 0.01f;
     museum->ef_sunshine_class.actor_class.scale.y = 0.01f;
@@ -61,15 +59,13 @@ void Ef_Room_Sunshine_Museum_actor_ct(ACTOR* actor, GAME* game){
             museum->ef_sunshine_class.actor_class.mv_proc = Ef_Room_Sunshine_MuseumL_actor_move;
             museum->ef_sunshine_class.actor_class.dw_proc = Ef_Room_Sunshine_MuseumL_actor_draw;
             museum->ef_sunshine_class.actor_class.world.position.x += 5.0f;
-            pos2 = museum->ef_sunshine_class.actor_class.world.position;
-            museum->ef_sunshine_class.actor_class.world.position.y = 1.0f + mCoBG_GetBgY_OnlyCenter_FromWpos(0.0f, &pos2) - 40.0f;
+            museum->ef_sunshine_class.actor_class.world.position.y = 1.0f + mCoBG_GetBgY_OnlyCenter_FromWpos(museum->ef_sunshine_class.actor_class.world.position, 0.0f) - 40.0f;
             museum->ef_sunshine_class.actor_class.world.position.x -= 6.0f;
         break;
 
         case 3:
             museum->ef_sunshine_class.actor_class.world.position.x -= 5.0f;
-            pos3 = museum->ef_sunshine_class.actor_class.world.position;
-            museum->ef_sunshine_class.actor_class.world.position.y = 1.0f + mCoBG_GetBgY_OnlyCenter_FromWpos(0.0f, &pos3) - 40.0f;
+            museum->ef_sunshine_class.actor_class.world.position.y = 1.0f + mCoBG_GetBgY_OnlyCenter_FromWpos(pos3 = museum->ef_sunshine_class.actor_class.world.position, 0.0f) - 40.0f;
             museum->ef_sunshine_class.actor_class.world.position.x += 6.0f;
         break;
     }
diff --git a/rel/ef_room_sunshine_police.c b/rel/ef_room_sunshine_police.c
index c4c3d002..d86a2201 100644
--- a/rel/ef_room_sunshine_police.c
+++ b/rel/ef_room_sunshine_police.c
@@ -45,9 +45,7 @@ void Ef_Room_Sunshine_Police_actor_ct(ACTOR* actor, GAME* game){
         police->ef_sunshine_class.actor_class.world.position.x -= 1.0f;
     }
 
-    pos = police->ef_sunshine_class.actor_class.world.position;
-    
-    police->ef_sunshine_class.actor_class.world.position.y = mCoBG_GetBgY_OnlyCenter_FromWpos(0.0f, &pos);
+    police->ef_sunshine_class.actor_class.world.position.y = mCoBG_GetBgY_OnlyCenter_FromWpos(police->ef_sunshine_class.actor_class.world.position, 0.0f);
 
     police->ef_sunshine_class.actor_class.scale.x = 0.01f;
     police->ef_sunshine_class.actor_class.scale.y = 0.01f;
@@ -60,15 +58,13 @@ void Ef_Room_Sunshine_Police_actor_ct(ACTOR* actor, GAME* game){
             police->ef_sunshine_class.actor_class.mv_proc = Ef_Room_Sunshine_PoliceL_actor_move;
             police->ef_sunshine_class.actor_class.dw_proc = Ef_Room_Sunshine_PoliceL_actor_draw;
             police->ef_sunshine_class.actor_class.world.position.x += 5.0f;
-            pos2 = police->ef_sunshine_class.actor_class.world.position;
-            police->ef_sunshine_class.actor_class.world.position.y = 1.0f + mCoBG_GetBgY_OnlyCenter_FromWpos(0.0f, &pos2) - 40.0f;
+            police->ef_sunshine_class.actor_class.world.position.y = 1.0f + mCoBG_GetBgY_OnlyCenter_FromWpos(police->ef_sunshine_class.actor_class.world.position, 0.0f) - 40.0f;
             police->ef_sunshine_class.actor_class.world.position.x -= 6.0f;
         break;
 
         case 3:
             police->ef_sunshine_class.actor_class.world.position.x -= 5.0f;
-            pos3 = police->ef_sunshine_class.actor_class.world.position;
-            police->ef_sunshine_class.actor_class.world.position.y = 1.0f + mCoBG_GetBgY_OnlyCenter_FromWpos(0.0f, &pos3) - 40.0f;
+            police->ef_sunshine_class.actor_class.world.position.y = 1.0f + mCoBG_GetBgY_OnlyCenter_FromWpos(police->ef_sunshine_class.actor_class.world.position, 0.0f) - 40.0f;
             police->ef_sunshine_class.actor_class.world.position.x += 6.0f;
         break;
     }
diff --git a/rel/ef_room_sunshine_posthouse.c b/rel/ef_room_sunshine_posthouse.c
index b31e1e26..3792ecf1 100644
--- a/rel/ef_room_sunshine_posthouse.c
+++ b/rel/ef_room_sunshine_posthouse.c
@@ -46,10 +46,8 @@ void Ef_Room_Sunshine_Posthouse_actor_ct(ACTOR* actor, GAME* game){
     else{
         posthouse->ef_sunshine_class.actor_class.world.position.x -= 1.0f;
     }
-
-    pos = posthouse->ef_sunshine_class.actor_class.world.position;
     
-    posthouse->ef_sunshine_class.actor_class.world.position.y = mCoBG_GetBgY_OnlyCenter_FromWpos(0.0f, &pos);
+    posthouse->ef_sunshine_class.actor_class.world.position.y = mCoBG_GetBgY_OnlyCenter_FromWpos(posthouse->ef_sunshine_class.actor_class.world.position, 0.0f);
 
     posthouse->ef_sunshine_class.actor_class.scale.x = 0.05f;
     posthouse->ef_sunshine_class.actor_class.scale.y = 0.05f;
@@ -62,15 +60,13 @@ void Ef_Room_Sunshine_Posthouse_actor_ct(ACTOR* actor, GAME* game){
             posthouse->ef_sunshine_class.actor_class.mv_proc = Ef_Room_Sunshine_PosthouseL_actor_move;
             posthouse->ef_sunshine_class.actor_class.dw_proc = Ef_Room_Sunshine_PosthouseL_actor_draw;
             posthouse->ef_sunshine_class.actor_class.world.position.x += 5.0f;
-            pos2 = posthouse->ef_sunshine_class.actor_class.world.position;
-            posthouse->ef_sunshine_class.actor_class.world.position.y = 1.0f + mCoBG_GetBgY_OnlyCenter_FromWpos(0.0f, &pos2);
+            posthouse->ef_sunshine_class.actor_class.world.position.y = 1.0f + mCoBG_GetBgY_OnlyCenter_FromWpos(posthouse->ef_sunshine_class.actor_class.world.position, 0.0f);
             posthouse->ef_sunshine_class.actor_class.world.position.x -= 6.0f;
         break;
 
         case 3:
             posthouse->ef_sunshine_class.actor_class.world.position.x -= 5.0f;
-            pos3 = posthouse->ef_sunshine_class.actor_class.world.position;
-            posthouse->ef_sunshine_class.actor_class.world.position.y = 1.0f + mCoBG_GetBgY_OnlyCenter_FromWpos(0.0f, &pos3);
+            posthouse->ef_sunshine_class.actor_class.world.position.y = 1.0f + mCoBG_GetBgY_OnlyCenter_FromWpos(posthouse->ef_sunshine_class.actor_class.world.position, 0.0f);
             posthouse->ef_sunshine_class.actor_class.world.position.x += 6.0f;
         break;
     }