Add anchor points to support manual movement between spaces (#26)

constants/script_constants.asm

@@ -107,6 +107,7 @@ DEF NUM_PLAYER_MOVEMENTS EQU const_value
 DEF SCENE_SCRIPT_SIZE EQU  4 ; scene_script
 DEF CALLBACK_SIZE     EQU  3 ; callback
 DEF WARP_EVENT_SIZE   EQU  5 ; warp_event
+DEF ANCHOR_EVENT_SIZE EQU  3 ; anchor_event
 DEF COORD_EVENT_SIZE  EQU  8 ; coord_event
 DEF BG_EVENT_SIZE     EQU  5 ; bg_event
 ; An object_event is a map_object without its initial MAPOBJECT_OBJECT_STRUCT_ID or final padding

constants/space_constants.asm

@@ -3,6 +3,14 @@ DEF FIRST_SPACE_METATILE        EQU $80
 DEF FIRST_GREY_SPACE_METATILE   EQU $e0
 DEF UNIQUE_SPACE_METATILES_MASK EQU %11111
 
+; reserved next space values that signal movement towards anchor point rather than towards space
+	const_def -1, -1
+	const GO_DOWN  ; 255
+	const GO_UP    ; 254
+	const GO_LEFT  ; 253
+	const GO_RIGHT ; 252
+DEF NEXT_SPACE_IS_ANCHOR_POINT EQU const_value + 1
+
 ; Branch Space special direction values
 DEF BRANCH_DIRECTION_INVALID     EQU -1
 DEF BRANCH_DIRECTION_UNAVAILABLE EQU -2

engine/board/movement.asm

@@ -1,5 +1,7 @@
 StepTowardsNextSpace::
 	ld a, [wCurSpaceNextSpace]
+	cp NEXT_SPACE_IS_ANCHOR_POINT
+	jr nc, .move_towards_anchor_point
 	call LoadTempSpaceData
 	ld a, [wTempSpaceXCoord]
 	ld c, a
@@ -27,3 +29,19 @@ StepTowardsNextSpace::
 .done
 	ld [wCurInput], a
 	ret
+
+.move_towards_anchor_point
+	ld c, D_DOWN
+	cp GO_DOWN
+	jr z, .done2
+	ld c, D_UP
+	cp GO_UP
+	jr z, .done2
+	ld c, D_LEFT
+	cp GO_LEFT
+	jr z, .done2
+	ld c, D_RIGHT
+.done2
+	ld a, c
+	ld [wCurInput], a
+	ret

engine/overworld/events.asm

@@ -357,6 +357,32 @@ CheckBoardEvent:
 .board
 	call CheckSpaceEffectsScriptFlag
 	jr z, .no_space_effect
+
+; anchor point handler
+; if wCurSpaceNextSpace is not an anchor point, override any anchor point we pass though
+	ld a, [wCurSpaceNextSpace]
+	cp NEXT_SPACE_IS_ANCHOR_POINT
+	jr c, .next
+	ld a, [wCurMapAnchorEventCount]
+	and a
+	jr z, .next
+; if we have arrived to an anchor point, load its associated next space to wCurSpaceNextSpace right now.
+; don't queue a script so that it happens transparently from the point of view of the player's movement.
+; note that the next space of an anchor point could be another anchor point.
+	ld c, a
+	ld hl, wCurMapAnchorEventsPointer
+	ld a, [hli]
+	ld h, [hl]
+	ld l, a
+	ld a, [wXCoord]
+	ld d, a
+	ld a, [wYCoord]
+	ld e, a
+	call CheckAndApplyAnchorPoint
+	ret nc ; if we applied an anchor point, we're done here (we're not in a space)
+
+.next
+; space handler
 	ld a, [wPlayerTile]
 	and $f0
 	cp HI_NYBBLE_SPACES

home/map.asm

@@ -244,12 +244,12 @@ GetDestinationWarpNumber::
 	ld a, [wPlayerMapX]
 	sub 4
 	ld d, a
-	ld a, [wCurMapWarpCount]
+	ld a, [wCurMapWarpEventCount]
 	and a
 	ret z
 
 	ld c, a
-	ld hl, wCurMapWarpsPointer
+	ld hl, wCurMapWarpEventsPointer
 	ld a, [hli]
 	ld h, [hl]
 	ld l, a
@@ -282,7 +282,7 @@ GetDestinationWarpNumber::
 	call .IncreaseHLTwice
 	ret nc ; never encountered
 
-	ld a, [wCurMapWarpCount]
+	ld a, [wCurMapWarpEventCount]
 	inc a
 	sub c
 	ld c, a
@@ -309,7 +309,7 @@ CopyWarpData::
 
 .CopyWarpData:
 	push bc
-	ld hl, wCurMapWarpsPointer
+	ld hl, wCurMapWarpEventsPointer
 	ld a, [hli]
 	ld h, [hl]
 	ld l, a
@@ -390,7 +390,8 @@ ReadMapEvents::
 	ld l, a
 	inc hl
 	inc hl
-	call ReadWarps
+	call ReadWarpEvents
+	call ReadAnchorEvents
 	call ReadCoordEvents
 	call ReadBGEvents
 
@@ -500,14 +501,14 @@ ReadMapCallbacks::
 	call AddNTimes
 	ret
 
-ReadWarps::
+ReadWarpEvents::
 	ld a, [hli]
 	ld c, a
-	ld [wCurMapWarpCount], a
+	ld [wCurMapWarpEventCount], a
 	ld a, l
-	ld [wCurMapWarpsPointer], a
+	ld [wCurMapWarpEventsPointer], a
 	ld a, h
-	ld [wCurMapWarpsPointer + 1], a
+	ld [wCurMapWarpEventsPointer + 1], a
 	ld a, c
 	and a
 	ret z
@@ -515,6 +516,23 @@ ReadWarps::
 	call AddNTimes
 	ret
 
+ReadAnchorEvents::
+	ld a, [hli]
+	ld c, a
+	ld [wCurMapAnchorEventCount], a
+	ld a, l
+	ld [wCurMapAnchorEventsPointer], a
+	ld a, h
+	ld [wCurMapAnchorEventsPointer + 1], a
+
+	ld a, c
+	and a
+	ret z
+
+	ld bc, ANCHOR_EVENT_SIZE
+	call AddNTimes
+	ret
+
 ReadCoordEvents::
 	ld a, [hli]
 	ld c, a
@@ -1783,6 +1801,44 @@ GetBlockLocation::
 	add hl, bc
 	ret
 
+CheckAndApplyAnchorPoint::
+; c = [wCurMapAnchorEventCount] (non-0)
+; d = [wXCoord]
+; e = [wYCoord]
+; hl = [wCurMapAnchorEventsPointer]
+; if currently at coords of any anchor point, copy its next space byte to wCurSpaceNextSpace.
+; return carry if anchor point matched, nc otherwise.
+	ldh a, [hROMBank]
+	push af
+	call SwitchToMapScriptsBank
+
+.loop
+	ld a, [hli]
+	cp d ; x
+	jr nz, .next1
+	ld a, [hli]
+	cp e ; y
+	jr nz, .next2
+
+; found anchor point in current player coords
+	ld a, [hl]
+	ld [wCurSpaceNextSpace], a
+	pop af
+	rst Bankswitch
+	xor a
+	ret
+
+.next1
+	inc hl
+.next2
+	inc hl
+	dec c
+	jr nz, .loop
+	pop af
+	rst Bankswitch
+	scf
+	ret
+
 CheckFacingBGEvent::
 	call GetFacingTileCoord
 ; Load facing into b.

home/stone_queue.asm

@@ -56,11 +56,11 @@ HandleStoneQueue::
 	ret
 
 .check_on_warp
-	ld hl, wCurMapWarpsPointer
+	ld hl, wCurMapWarpEventsPointer
 	ld a, [hli]
 	ld h, [hl]
 	ld l, a
-	ld a, [wCurMapWarpCount]
+	ld a, [wCurMapWarpEventCount]
 	and a
 	jr z, .nope2
 
@@ -94,7 +94,7 @@ HandleStoneQueue::
 .found_warp
 	pop af
 	ld d, a
-	ld a, [wCurMapWarpCount]
+	ld a, [wCurMapWarpEventCount]
 	sub d
 	inc a
 	scf

macros/scripts/maps.asm

@@ -62,6 +62,21 @@ MACRO warp_event
 	DEF {_NUM_WARP_EVENTS} += 1
 ENDM
 
+MACRO def_anchor_events
+	REDEF _NUM_ANCHOR_EVENTS EQUS "_NUM_ANCHOR_EVENTS_\@"
+	db {_NUM_ANCHOR_EVENTS}
+	DEF {_NUM_ANCHOR_EVENTS} = 0
+ENDM
+
+MACRO anchor_event
+;\1: x coord
+;\2: y coord
+;\3: next space
+; there is no \4. An anchor point can't act as an space with an effect (neither as a branch space)
+	db \1, \2, \3
+	DEF {_NUM_ANCHOR_EVENTS} += 1
+ENDM
+
 MACRO def_coord_events
 	REDEF _NUM_COORD_EVENTS EQUS "_NUM_COORD_EVENTS_\@"
 	db {_NUM_COORD_EVENTS}

maps/DebugLevel1_Map1.asm

@@ -16,6 +16,8 @@ DebugLevel1_Map1_MapEvents:
 	def_warp_events
 	warp_event  7,  0, LEVEL_1_MAP_1, 1
 
+	def_anchor_events
+
 	def_coord_events
 
 	def_bg_events

maps/DebugLevel2_Map1.asm

@@ -10,6 +10,8 @@ DebugLevel2_Map1_MapEvents:
 
 	def_warp_events
 
+	def_anchor_events
+
 	def_coord_events
 
 	def_bg_events

maps/DebugLevel3_Map1.asm

@@ -10,6 +10,8 @@ DebugLevel3_Map1_MapEvents:
 
 	def_warp_events
 
+	def_anchor_events
+
 	def_coord_events
 
 	def_bg_events

maps/DebugLevel4_Map1.asm

@@ -10,6 +10,8 @@ DebugLevel4_Map1_MapEvents:
 
 	def_warp_events
 
+	def_anchor_events
+
 	def_coord_events
 
 	def_bg_events

maps/DebugLevel5_Map1.asm

@@ -10,6 +10,10 @@ DebugLevel5_Map1_MapEvents:
 
 	def_warp_events
 
+	def_anchor_events
+	anchor_event 10,  1, GO_RIGHT
+	anchor_event 12,  1, 39
+
 	def_coord_events
 
 	def_bg_events
@@ -58,7 +62,7 @@ DebugLevel5_Map1_MapSpaces:
 	space  6,  2,  $0, 36 ; 35
 	space  6,  0,  $0, 37 ; 36
 	space  8,  0,  $0, 38 ; 37
-	space 10,  0,  $0, 39 ; 38
+	space 10,  0,  $0, GO_DOWN ; 38
 	space 12,  0,  $0, 40 ; 39
 	space 14,  0,  $0, 41 ; 40
 	space 16,  0,  $0, 42 ; 41

maps/DebugLevel5_Map1.blk

@@ -1 +1 @@
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maps/DebugLevel5_Map1.blk.bak

@@ -1 +0,0 @@
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maps/Level1_Map1.asm

@@ -16,6 +16,8 @@ Level1_Map1_MapEvents:
 	def_warp_events
 	warp_event  7,  0, LEVEL_1_MAP_1, 1
 
+	def_anchor_events
+
 	def_coord_events
 
 	def_bg_events

ram/wram.asm

@@ -1597,6 +1597,13 @@ wElevatorPointer:: dw
 wElevatorOriginFloor:: db
 wElevatorDataEnd::
 
+NEXTU
+; anchor event data
+wCurAnchorEvent::
+wCurAnchorEventXCoord:: db
+wCurAnchorEventYCoord:: db
+wCurAnchorEventNextSpace:: db
+
 NEXTU
 ; coord event data
 wCurCoordEvent::
@@ -2434,8 +2441,10 @@ wBikeFlags::
 wCurMapSceneScriptPointer:: dw
 
 wCurCaller:: dw
-wCurMapWarpCount:: db
+wCurMapWarpEventCount:: db
-wCurMapWarpsPointer:: dw
+wCurMapWarpEventsPointer:: dw
+wCurMapAnchorEventCount:: db
+wCurMapAnchorEventsPointer:: dw
 wCurMapCoordEventCount:: db
 wCurMapCoordEventsPointer:: dw
 wCurMapBGEventCount:: db