d_a_bg_obj almost matching (#2382)

include/d/actor/d_a_bg_obj.h

@@ -110,7 +110,7 @@ public:
     /* 0xCCA */ u16 field_0xcca;
     /* 0xCCC */ u16 field_0xccc;
     /* 0xCD0 */ spec_data_c mSpecData;
-    /* 0xCF4 */ csXyz field_0xcf4;
+    /* 0xCF4 */ csXyz mRotation;
     /* 0xCFC */ u32 mAttnActorID;
     /* 0xD00 */ u8 field_0xd00;
     /* 0xD01 */ u8 field_0xd01;

include/m_Do/m_Do_mtx.h

@@ -345,6 +345,10 @@ public:
         MTXRotAxisRad(now, axis, rad);
     }
 
+    static void identity() {
+        MTXIdentity(now);
+    }
+
     static Mtx now;
     static Mtx buffer[16];
     static Mtx* next;