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Routines |
| Prev: 54251 | Up: Map | Next: 54701 |
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Used by the routine at TestEntityCollisions.
Tests whether two entities overlap on x, then y, then z, using TestOverlap. The three extents are fields 11 12 and 13. The y test and the z test move IX so that those extents sit at the displacement the test reads. An overlap is stored at OverlapDistances for x, 56785 for y and 56787 for z. A puff with no width flags then scores, from the table at ScoreTable, and becomes a sparkle. A whirler meeting the player, a spider and a shot all burst. A shot is then removed. A pickup is collected with CollectItem, and the player is moved clear with HandleOverlap_Compare.
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| TestEntityPair | 54394 | LD H,(IY+2) | Fetch the other entity's x coordinate. | |||||||
| 54397 | LD L,(IY+3) | |||||||||
| 54400 | LD D,(IX+2) | Fetch this entity's x coordinate. | ||||||||
| 54403 | LD E,(IX+3) | |||||||||
| 54406 | LD C,(IY+11) | Fetch the other entity's x extent. | ||||||||
| 54409 | LD B,(IX+11) | Fetch this entity's x extent. | ||||||||
| 54412 | CALL TestOverlap | Test the two x ranges. | ||||||||
| 54415 | RET NC | Return if the x ranges do not overlap. | ||||||||
| 54416 | INC L | Remember the x overlap. | ||||||||
| 54417 | LD (56783),HL | |||||||||
| 54420 | LD H,(IY+5) | Fetch the other entity's y coordinate. | ||||||||
| 54423 | LD L,(IY+6) | |||||||||
| 54426 | LD D,(IX+5) | Fetch this entity's y coordinate. | ||||||||
| 54429 | LD E,(IX+6) | |||||||||
| 54432 | LD C,(IY+12) | Fetch the other entity's y extent. | ||||||||
| 54435 | LD B,(IX+12) | Fetch this entity's y extent. | ||||||||
| 54438 | INC IX | Aim the test at the y extent. | ||||||||
| 54440 | CALL TestOverlap | Test the two y ranges. | ||||||||
| 54443 | DEC IX | Restore the entity address. | ||||||||
| 54445 | RET NC | Return if the y ranges do not overlap. | ||||||||
| 54446 | INC L | Remember the y overlap. | ||||||||
| 54447 | LD (56785),HL | |||||||||
| 54450 | LD H,(IY+8) | Fetch the other entity's z coordinate. | ||||||||
| 54453 | LD L,(IY+9) | |||||||||
| 54456 | LD D,(IX+8) | Fetch this entity's z coordinate. | ||||||||
| 54459 | LD E,(IX+9) | |||||||||
| 54462 | PUSH IX | Aim the test at the z extent. | ||||||||
| 54464 | LD BC,65530 | |||||||||
| 54467 | ADD IX,BC | |||||||||
| 54469 | LD C,(IY+13) | Fetch the other entity's z extent. | ||||||||
| 54472 | LD B,(IX+19) | Fetch this entity's z extent. | ||||||||
| 54475 | CALL TestOverlap | Test the two z ranges. | ||||||||
| 54478 | POP IX | Restore the entity address. | ||||||||
| 54480 | RET NC | Return if the z ranges do not overlap. | ||||||||
| 54481 | INC L | Remember the z overlap. | ||||||||
| 54482 | LD (56787),HL | |||||||||
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A puff whose width flags are clear scores and becomes a sparkle.
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| 54485 | LD A,(IY+22) | Leave this reward unless the width flags are clear. | ||||||||
| 54488 | AND 240 | |||||||||
| 54490 | JR NZ,TestEntityPair_0 | |||||||||
| 54492 | LD A,(IY+0) | Score only when the other entity is a puff. | ||||||||
| 54495 | CP 5 | |||||||||
| 54497 | JR NZ,TestEntityPair_0 | |||||||||
| 54499 | LD A,(IX+0) | Use this entity's type as an index into the score table. | ||||||||
| 54502 | ADD A,A | |||||||||
| 54503 | LD HL,54715 | Take the score table. | ||||||||
| 54506 | CALL AddToAddress | Look the score up. | ||||||||
| 54509 | LD B,(HL) | Read the score. | ||||||||
| 54510 | INC HL | |||||||||
| 54511 | LD C,(HL) | |||||||||
| 54512 | CALL AddScore | Add the score. | ||||||||
| 54515 | CALL StartBurst | Start a burst. | ||||||||
| 54518 | LD (IY+0),13 | Turn the puff into a sparkle. | ||||||||
| 54522 | LD (IY+1),0 | Clear the sparkle's frame. | ||||||||
| 54526 | LD (IY+23),8 | Set the sparkle's height to 8. | ||||||||
| 54530 | LD (IY+35),4 | Set the sparkle's countdown to 4. | ||||||||
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Nothing else happens while the countdown timer is running. The other entity is in IY.
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| TestEntityPair_0 | 54534 | LD A,(41695) | Return while the countdown timer is running. | |||||||
| 54537 | AND A | |||||||||
| 54538 | RET NZ | |||||||||
| 54539 | LD A,(IY+22) | Read the other entity's width byte. | ||||||||
| 54542 | AND %11110000 | Use the countdown nibble. | ||||||||
| 54544 | JR NZ,TestEntityPair_Spider | Skip the whirler test when that nibble is set. | ||||||||
| 54546 | LD A,(IY+0) | Read the other entity's type. | ||||||||
| 54549 | DEC A | The other entity is the player. | ||||||||
| 54550 | JR NZ,TestEntityPair_Whirler | |||||||||
| 54552 | LD A,(IX+0) | A whirler bursts the player. | ||||||||
| 54555 | CP 17 | |||||||||
| 54557 | JR NZ,TestEntityPair_Spider | |||||||||
| 54559 | JR TestEntityPair_Burst | Burst them. | ||||||||
| TestEntityPair_Whirler | 54561 | CP 16 | The other entity is a whirler. | |||||||
| 54563 | JR NZ,TestEntityPair_Spider | |||||||||
| 54565 | LD A,(IX+0) | This entity is the player. | ||||||||
| 54568 | DEC A | |||||||||
| 54569 | JR NZ,TestEntityPair_Spider | Leave the pair when it is not. | ||||||||
| TestEntityPair_Burst | 54571 | CALL StartBurst | Burst the other entity. | |||||||
| 54574 | CALL BurstOtherEntity | Finish bursting it. | ||||||||
| TestEntityPair_Spider | 54577 | LD A,(IY+0) | A spider bursts. | |||||||
| 54580 | CP 16 | |||||||||
| 54582 | CALL Z,StartBurst | |||||||||
| 54585 | LD A,(IY+0) | A shot bursts and is removed. | ||||||||
| 54588 | CP 14 | |||||||||
| 54590 | JR NZ,TestEntityPair_Pickup | |||||||||
| 54592 | CALL StartBurst | Burst the shot. | ||||||||
| 54595 | LD (IY+0),0 | Remove the shot. | ||||||||
| 54599 | LD (IY+1),128 | Hide what remains of it. | ||||||||
| TestEntityPair_Pickup | 54603 | LD A,(IY+0) | A pickup is collected. | |||||||
| 54606 | CP 15 | |||||||||
| 54608 | CALL Z,CollectItem | |||||||||
| 54611 | LD A,(IX+0) | The player is moved clear of the overlap. | ||||||||
| 54614 | DEC A | |||||||||
| 54615 | JP Z,HandleOverlap_Compare | |||||||||
| 54618 | CP 14 | A shot is collected from the other side. | ||||||||
| 54620 | JR NZ,TestEntityPair_Clear | |||||||||
| 54622 | PUSH IY | Swap the two entities. | ||||||||
| 54624 | PUSH IX | |||||||||
| 54626 | POP IY | |||||||||
| 54628 | POP IX | |||||||||
| 54630 | CALL CollectItem | Collect the item. | ||||||||
| 54633 | PUSH IY | Swap the two entities back. | ||||||||
| 54635 | PUSH IX | |||||||||
| 54637 | POP IY | |||||||||
| 54639 | POP IX | |||||||||
| TestEntityPair_Clear | 54641 | XOR A | Clear the handled flag. | |||||||
| 54642 | LD (54692),A | |||||||||
| 54645 | LD HL,(56787) | Reduce the z overlap by one. | ||||||||
| 54648 | DEC L | |||||||||
| 54649 | LD (56787),HL | |||||||||
| 54652 | LD HL,(56783) | Reduce the x overlap by two. | ||||||||
| 54655 | DEC L | |||||||||
| 54656 | DEC L | |||||||||
| 54657 | LD (56783),HL | |||||||||
| 54660 | LD HL,(56785) | Reduce the y overlap by two. | ||||||||
| 54663 | DEC L | |||||||||
| 54664 | DEC L | |||||||||
| 54665 | LD (56785),HL | |||||||||
| 54668 | LD C,(IX+31) | Remember the flags and field 31. | ||||||||
| 54671 | LD B,(IX+30) | |||||||||
| 54674 | PUSH BC | |||||||||
| 54675 | CALL HandleOverlap_Compare | Move the entity clear of the overlap. | ||||||||
| 54678 | POP BC | Bring the saved values back. | ||||||||
| 54679 | LD (IX+31),C | Restore field 31. | ||||||||
| 54682 | LD A,B | Use bit 6 of the saved flags. | ||||||||
| 54683 | AND 64 | |||||||||
| 54685 | OR (IX+30) | Keep that bit in the flags. | ||||||||
| 54688 | LD (IX+30),A | |||||||||
| 54691 | LD A,0 | Return unless the patched kind is 11. | ||||||||
| 54693 | CP 11 | |||||||||
| 54695 | RET NZ | |||||||||
| 54696 | LD A,(IY+0) | Return unless the other entity is the player. | ||||||||
| 54699 | DEC A | |||||||||
| 54700 | RET NZ | |||||||||
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Continue on to BurstOtherEntity.
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| Prev: 54251 | Up: Map | Next: 54701 |