Implement Rock Smash technique (#34)

engine/events/overworld.asm

@@ -1358,7 +1358,7 @@ RockSmashScript:
 	playsound SFX_STRENGTH
 	earthquake 84
 	applymovementlasttalked MovementData_RockSmash
-	disappear -2
+	disappear LAST_TALKED
 
 	callasm RockMonEncounter
 	readmem wTempWildMonSpecies
@@ -1369,6 +1369,15 @@ RockSmashScript:
 .done
 	end
 
+RockSmashAutoScript::
+	special WaitSFX
+	playsound SFX_STRENGTH
+	earthquake 84
+	applymovementlasttalked MovementData_RockSmash
+	disappear LAST_TALKED
+	special SetObjectToRemainHidden
+	end
+
 MovementData_RockSmash:
 	rock_smash 10
 	step_end

engine/overworld/events.asm

@@ -360,6 +360,9 @@ PlayerEvents:
 	call DisableTileEvents ; preserves f
 	jr c, .ok
 
+	call CheckFacingTileEvent
+	jr c, .ok
+
 	call RunMemScript
 	jr c, .ok
 
@@ -637,6 +640,86 @@ SetMinTwoStepWildEncounterCooldown: ; unreferenced
 	ld [wWildEncounterCooldown], a
 	ret
 
+CheckFacingTileEvent:
+	ldh a, [hCurBoardEvent]
+	cp BOARDEVENT_VIEW_MAP_MODE
+	jr z, .NoAction
+
+	call .TryObjectEvent
+	jr c, .Action
+	; fallthrough
+
+.NoAction:
+	xor a
+	ret
+
+.Action:
+	push af
+	farcall StopPlayerForEvent
+	pop af
+	scf
+	ret
+
+.TryObjectEvent:
+	farcall CheckFacingObject
+	jr c, .IsObject
+	xor a
+	ret
+
+.IsObject:
+	ldh a, [hObjectStructIndex]
+	call GetObjectStruct
+	ld hl, OBJECT_MAP_OBJECT_INDEX
+	add hl, bc
+	ld a, [hl]
+	ldh [hLastTalked], a
+
+	ldh a, [hLastTalked]
+	call GetMapObject
+	ld hl, MAPOBJECT_TYPE
+	add hl, bc
+	ld a, [hl]
+	and MAPOBJECT_TYPE_MASK
+
+	push bc
+	ld de, 3
+	ld hl, .ObjectEventTypeArray
+	call IsInArray
+	pop bc
+	jr nc, .nope
+
+	inc hl
+	ld a, [hli]
+	ld h, [hl]
+	ld l, a
+	jp hl
+
+.nope
+	xor a
+	ret
+
+.ObjectEventTypeArray:
+	table_width 3, .ObjectEventTypeArray
+	dbw OBJECTTYPE_SCRIPT, .none
+	dbw OBJECTTYPE_ITEMBALL, .none
+	dbw OBJECTTYPE_TRAINER, .none
+	dbw OBJECTTYPE_TALKER, .none
+	dbw OBJECTTYPE_ROCK, .rock_smash
+	dbw OBJECTTYPE_5, .none
+	dbw OBJECTTYPE_6, .none
+	assert_table_length NUM_OBJECT_TYPES
+	db -1 ; end
+
+.none
+	xor a
+	ret ; nc
+
+.rock_smash
+	ld a, BANK(RockSmashAutoScript)
+	ld hl, RockSmashAutoScript
+	call CallScript
+	ret ; c
+
 RunSceneScript:
 	ldh a, [hCurBoardEvent]
 	cp BOARDEVENT_VIEW_MAP_MODE
@@ -824,7 +907,7 @@ ObjectEventTypeArray:
 	dbw OBJECTTYPE_TRAINER, .trainer
 	; the remaining four are dummy events
 	dbw OBJECTTYPE_TALKER, .three
-	dbw OBJECTTYPE_4, .four
+	dbw OBJECTTYPE_ROCK, .four
 	dbw OBJECTTYPE_5, .five
 	dbw OBJECTTYPE_6, .six
 	assert_table_length NUM_OBJECT_TYPES

engine/overworld/map_objects.asm

@@ -2750,6 +2750,21 @@ ResetObject:
 	db SPRITEMOVEDATA_STANDING_LEFT
 	db SPRITEMOVEDATA_STANDING_RIGHT
 
+; Used to make the last talked object remain hidden.
+; This is done by setting its event flag to special value ALWAYS_HIDDEN.
+; Otherwise when data is read from wMapObjectsBackups after entering the map,
+; it would appear by default even if it had been made disappear.
+SetObjectToRemainHidden:
+	ldh a, [hLastTalked]
+	call GetMapObject
+	ld hl, MAPOBJECT_EVENT_FLAG
+	add hl, bc
+	ld de, ALWAYS_HIDDEN
+	ld [hl], e
+	inc hl
+	ld [hl], d
+	ret
+
 _UpdateActiveSpritesAfterOffset::
 	ld a, [wVramState]
 	bit 0, a

engine/overworld/map_objects_2.asm

@@ -41,10 +41,10 @@ CheckObjectFlag:
 	ld e, a
 	ld a, [hl]
 	ld d, a
-	cp -1
+	cp HIGH(ALWAYS_SHOWN) ; HIGH(ALWAYS_HIDDEN)
 	jr nz, .check
 	ld a, e
-	cp -1
+	cp LOW(ALWAYS_SHOWN)
 	jr z, .unmasked
 	jr .masked
 .check

engine/overworld/scripting.asm

@@ -1007,16 +1007,14 @@ ApplyEventActionAppearDisappear:
 	ld e, [hl]
 	inc hl
 	ld d, [hl]
-	ld a, -1
-	cp e
-	jr nz, .okay
+	ld a, HIGH(ALWAYS_SHOWN) ; HIGH(ALWAYS_HIDDEN)
 	cp d
-	jr nz, .okay
-	xor a
-	ret
-.okay
+	jr z, .not_a_flag
 	call EventFlagAction
 	ret
+.not_a_flag
+	xor a
+	ret
 
 Script_follow:
 	call GetScriptByte