mirror of https://github.com/pret/pokecrystal.git
84 lines
2.0 KiB
NASM
84 lines
2.0 KiB
NASM
CheckForHiddenItems:
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; Checks to see if there are hidden items on the screen that have not yet been found. If it finds one, returns carry.
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call GetMapScriptsBank
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ld [wCurMapScriptBank], a
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; Get the coordinate of the bottom right corner of the screen, and load it in wBottomRightYCoord/wBottomRightXCoord.
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ld a, [wXCoord]
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add SCREEN_WIDTH / 4
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ld [wBottomRightXCoord], a
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ld a, [wYCoord]
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add SCREEN_HEIGHT / 4
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ld [wBottomRightYCoord], a
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; Get the pointer for the first bg_event in the map...
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ld hl, wCurMapBGEventsPointer
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ld a, [hli]
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ld h, [hl]
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ld l, a
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; ... before even checking to see if there are any BG events on this map.
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ld a, [wCurMapBGEventCount]
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and a
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jr z, .nobgeventitems
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; For i = 1:wCurMapBGEventCount...
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.loop
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; Store the counter in wRemainingBGEventCount, and store the bg_event pointer in the stack.
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ld [wRemainingBGEventCount], a
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push hl
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; Get the Y coordinate of the BG event.
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call .GetFarByte
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ld e, a
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; Is the Y coordinate of the BG event on the screen? If not, go to the next BG event.
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ld a, [wBottomRightYCoord]
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sub e
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jr c, .next
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cp SCREEN_HEIGHT / 2
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jr nc, .next
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; Is the X coordinate of the BG event on the screen? If not, go to the next BG event.
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call .GetFarByte
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ld d, a
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ld a, [wBottomRightXCoord]
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sub d
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jr c, .next
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cp SCREEN_WIDTH / 2
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jr nc, .next
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; Is this BG event a hidden item? If not, go to the next BG event.
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call .GetFarByte
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cp BGEVENT_ITEM
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jr nz, .next
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; Has this item already been found? If not, set off the Itemfinder.
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ld a, [wCurMapScriptBank]
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call GetFarHalfword
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ld a, [wCurMapScriptBank]
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call GetFarHalfword
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ld d, h
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ld e, l
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ld b, CHECK_FLAG
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call EventFlagAction
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ld a, c
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and a
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jr z, .itemnearby
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.next
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; Restore the bg_event pointer and increment it by the length of a bg_event.
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pop hl
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ld bc, BG_EVENT_SIZE
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add hl, bc
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; Restore the BG event counter and decrement it. If it hits zero, there are no hidden items in range.
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ld a, [wRemainingBGEventCount]
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dec a
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jr nz, .loop
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.nobgeventitems
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xor a
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ret
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.itemnearby
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pop hl
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scf
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ret
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.GetFarByte:
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ld a, [wCurMapScriptBank]
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call GetFarByte
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inc hl
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ret
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