Routines
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29429: Bug Collision
Used by the routine at 25837.
Input
IX Bug object
Output
E 0 no collision
E 1 collision
BugCollision 29429 LD HL,24172 HL=State_Robbie_Active.
29432 LD E,0 E=Default value 0 (no collision).
29434 LD A,(HL) A=State_Robbie_Active.
29435 AND %00111111 Keep only bits 0-5.
29437 DEC A Decrease A by one.
29438 JR Z,BugCollision_X If A is zero then jump to BugCollision_X.
29440 DEC A
29441 RET NZ
BugCollision_X 29442 INC HL A=State_Robbie_Pos_X.
29443 LD A,(HL)
29444 SUB (IX+1) Robbie X position - bug X Position.
29447 JP P,BugCollision_Test_X Make sure we have a positive byte.
29450 NEG
BugCollision_Test_X 29452 CP 16 Return if A >= 16.
29454 RET NC
29455 INC HL A=State_Robbie_Pos_Y.
This entry point is used by the routine at 29282.
BugCollision_0 29456 LD A,(HL) }
29457 SUB (IX+2) Robbie Y position - bug Y position.
29460 JP P,BugCollision_SetHeight Set D to 18 if it's a positive number.
29463 NEG
29465 LD D,(IX+7) D=bug sprite height.
29468 JR BugCollision_Test_Y Jump to BugCollision_Test_Y.
BugCollision_SetHeight 29470 LD D,18 D=18.
BugCollision_Test_Y 29472 CP D Return if D >= A.
29473 RET NC
A collision has been detected.
29474 LD E,1 E=1.
29476 RET Return.
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