Define more bit flag constants

constants/map_object_constants.asm

@@ -52,6 +52,11 @@ FIXED_FACING EQU 2
 SLIDING      EQU 3
 EMOTE_OBJECT EQU 7
 
+; object_struct OBJECT_FLAGS2 bit flags
+LOW_PRIORITY  EQU 0
+HIGH_PRIORITY EQU 1
+OVERHEAD      EQU 3
+
 
 ; map_object struct members (see macros/wram.asm)
 	const_def

engine/map_objects.asm

@@ -233,7 +233,7 @@ Function462a: ; 462a
 UpdateTallGrassFlags: ; 463f
 	ld hl, OBJECT_FLAGS2
 	add hl, bc
-	bit 3, [hl] ; is current tile grass?
+	bit OVERHEAD, [hl]
 	jr z, .ok
 	ld hl, OBJECT_NEXT_TILE
 	add hl, bc
@@ -260,13 +260,13 @@ SetTallGrassFlags: ; 4661
 .set
 	ld hl, OBJECT_FLAGS2
 	add hl, bc
-	set 3, [hl]
+	set OVERHEAD, [hl]
 	ret
 
 .reset
 	ld hl, OBJECT_FLAGS2
 	add hl, bc
-	res 3, [hl]
+	res OVERHEAD, [hl]
 	ret
 ; 4679
 
@@ -2918,10 +2918,10 @@ InitSprites: ; 5991
 	ld e, PRIORITY_LOW
 	ld hl, OBJECT_FLAGS2
 	add hl, bc
-	bit 0, [hl]
+	bit LOW_PRIORITY, [hl]
 	jr nz, .add
 	ld e, PRIORITY_NORM
-	bit 1, [hl]
+	bit HIGH_PRIORITY, [hl]
 	jr z, .add
 	ld e, PRIORITY_HIGH
 	jr .add

engine/movement.asm

@@ -838,7 +838,7 @@ JumpStep: ; 548a
 
 	ld hl, OBJECT_FLAGS2
 	add hl, bc
-	res 3, [hl]
+	res OVERHEAD, [hl]
 
 	ld hl, OBJECT_ACTION
 	add hl, bc