Routines
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48498: Test Thing Upstairs Overlap
Used by the routine at ScriptRoutine_ThingUpstairsChase.
Return 1 in A when the Thing Upstairs entity overlaps Berk on X (BerkXCoordinateCopy / BerkXExtentCopy) and the camera-follow entity (StateData_Berk) on Y while Berk's room copy is 0. Otherwise return 0.
Input
IX Address of the Thing Upstairs entity's complex state data
Horizontal overlap against Berk's X / X-extent copies.
Test_ThingUpstairs_Overlap 48498 LD A,(29444) Load Berk's X-extent copy (BerkXExtentCopy) into A.
48501 DEC A Step that right edge back by one.
48502 CP (IX+7) Is Berk's right edge left of the Thing Upstairs entity's left edge (IX+7)? If so, no overlap, so return.
48505 RET C
48506 LD A,(29443) Load Berk's X-coordinate copy (BerkXCoordinateCopy) into A.
48509 CP (IX+8) Is Berk's left edge at or beyond the Thing Upstairs entity's right edge (IX+8)? If so, no overlap, so return.
48512 RET NC
Vertical overlap against the camera-follow entity.
48513 LD A,(IX+6) Load the Thing Upstairs entity's y-extent (bottom edge) into A.
48516 LD IY,37019 Point IY at the camera-follow entity (StateData_Berk).
48520 LD C,(IY+6) Load the camera-follow entity's y-extent into C.
48523 CP (IY+5) Is the Thing Upstairs entity's bottom above the camera-follow entity's top (IY+5)? If so, no overlap, so return.
48526 RET C
48527 LD A,(IX+5) Load the Thing Upstairs entity's y-coordinate (top edge) into A.
48530 INC A Advance that top edge by two.
48531 INC A
48532 CP C Is that raised top at or below the camera-follow entity's bottom in C? If so, no overlap, so return.
48533 RET NC
Accept only when Berk's room copy is 0.
48534 LD A,(29445) Load Berk's room-index copy (BerkRoomIndexCopy) into A.
48537 OR A Is Berk in room 0? If not, jump to Test_ThingUpstairs_Overlap_NoMatch.
48538 JR NZ,Test_ThingUpstairs_Overlap_NoMatch
48540 INC A Set A to 1 as a successful overlap result.
48541 RET Return.
No Thing Upstairs overlap (wrong room or miss): return 0 in A.
Test_ThingUpstairs_Overlap_NoMatch 48542 XOR A Clear A as a false / no-match result.
48543 RET Return.
This entry point is used by the routine at Update_ThingUpstairs_Entity.
Entry from Update_ThingUpstairs_Entity when slot 32 is not Thing Upstairs: maybe arm the Thing Upstairs script/sound.
Update_ThingUpstairs_Entity_ArmSpawn 48544 LD A,(29363) Load A with the game event flags (GameEventFlags).
48547 BIT 1,A Is "trap door is open / trap door event armed" (bit 1 of GameEventFlags) set? If not, return.
48549 RET Z
48550 LD A,60 Load A with random maximum 60.
48552 CALL PseudoRandom Call PseudoRandom to pick a pseudo-random value.
48555 OR A Is that random value zero? If not, return.
48556 RET NZ
48557 LD A,136 Load A with 136.
48559 CALL Queue_Sound Call Queue_Sound to queue a sound effect.
48562 LD HL,29363 Point HL at the game event flags (GameEventFlags).
48565 SET 4,(HL) Set "task-two / upstairs event latch" (bit 4 of GameEventFlags).
48567 LD HL,48096 Point HL at the Thing Upstairs script (48096).
48570 LD (29401),HL Store HL in Pointer_ThingUpstairsScriptPosition.
48573 LD A,34 Load A with 34.
48575 LD (36865),A Store A in complex entity slot 32's type (StateData_Complex_20).
48578 RET Return.
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