Verify the battle BG effect pointer table length

Author: Rangi42

constants/battle_anim_constants.asm

@@ -719,7 +719,8 @@ assert NUM_BATTLE_ANIM_OAMSETS <= FIRST_OAM_CMD, \
 	"BATTLE_ANIM_OAMSET_* constants overlap oam*_command constants"
 
 ; BattleBGEffects indexes (see engine/battle_anims/bg_effects.asm)
-	const_def 1
+	const_def
+	const BATTLE_BG_EFFECT_END                              ; 00
 	const BATTLE_BG_EFFECT_FLASH_INVERTED                   ; 01
 	const BATTLE_BG_EFFECT_FLASH_WHITE                      ; 02
 	const BATTLE_BG_EFFECT_WHITE_HUES                       ; 03
@@ -773,7 +774,7 @@ assert NUM_BATTLE_ANIM_OAMSETS <= FIRST_OAM_CMD, \
 	const BATTLE_BG_EFFECT_VIBRATE_MON                      ; 33
 	const BATTLE_BG_EFFECT_WOBBLE_PLAYER                    ; 34
 	const BATTLE_BG_EFFECT_WOBBLE_SCREEN                    ; 35
-DEF NUM_BATTLE_BG_EFFECTS EQU const_value - 1
+DEF NUM_BATTLE_BG_EFFECTS EQU const_value
 
 ; wBattleAnimTileDict keys (see wram.asm)
 ; AnimObjGFX indexes (see data/battle_anims/object_gfx.asm)

engine/battle_anims/bg_effects.asm

@@ -79,6 +79,7 @@ DoBattleBGEffectFunction:
 
 BattleBGEffects:
 ; entries correspond to BATTLE_BG_EFFECT_* constants
+	table_width 2
 	dw BattleBGEffect_End
 	dw BattleBGEffect_FlashInverted
 	dw BattleBGEffect_FlashWhite
@@ -133,6 +134,7 @@ BattleBGEffects:
 	dw BattleBGEffect_VibrateMon
 	dw BattleBGEffect_WobblePlayer
 	dw BattleBGEffect_WobbleScreen
+	assert_table_length NUM_BATTLE_BG_EFFECTS
 
 BattleBGEffect_End:
 	call EndBattleBGEffect