Implement clearing level in RAM according to End Space effect, supporting up to 4 clearable stages per level; Implement unlocking levels [Commit 1] (#35)

data/levels/levels.asm

@@ -0,0 +1,41 @@
+MACRO level_unlock_req
+
+; a list of levels that must be cleared (each must be in the form of: <Level>, STAGE_*)
+if !STRCMP("\1", "LEVELS_CLEARED")
+	db UNLOCK_WHEN_\1
+	rept (_NARG - 1) / 2
+		db \2, \3
+		shift
+		shift
+	endr
+
+; an amount of levels that must be cleared (regardless of stage)
+elif !STRCMP("\1", "NUMBER_OF_LEVELS_CLEARED")
+	db UNLOCK_WHEN_\1
+	db \2
+
+; a list of techniques that must be cleared
+elif !STRCMP("\1", "TECHNIQUES_CLEARED")
+	db UNLOCK_WHEN_\1
+	rept _NARG - 1
+		db \2
+		shift
+	endr
+
+; else no requirements
+endc
+	db $ff
+	REDEF x += 1
+ENDM
+
+LevelUnlockRequirements:
+DEF x = 0
+	level_unlock_req NONE ; LEVEL_1 (irrelevant)
+if DEF(_DEBUG)
+	level_unlock_req NONE ; DEBUGLEVEL_1
+	level_unlock_req LEVELS_CLEARED, DEBUGLEVEL_1, STAGE_1 ; DEBUGLEVEL_2
+	level_unlock_req LEVELS_CLEARED, DEBUGLEVEL_2, STAGE_1 ; DEBUGLEVEL_3
+	level_unlock_req LEVELS_CLEARED, DEBUGLEVEL_3, STAGE_1 ; DEBUGLEVEL_4
+	level_unlock_req LEVELS_CLEARED, DEBUGLEVEL_4, STAGE_1 ; DEBUGLEVEL_5
+endc
+	assert x == NUM_LEVELS