Routines
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42298: Spawn Linked Object
Used by the routine at Handler_AlienBasePlasma.
If the next actor slot is free, write type 200 into it and copy a speed and thrust pair from Handler_PlayerShot_Table.
Input
IX Actor slot
Write type 200 into the next slot if it is free.
SpawnLinkedObject 42298 PUSH IX Copy the slot pointer into HL (using the stack).
42300 POP HL
42301 LD DE,24 DE=0024.
42304 ADD HL,DE Move onto the next slot.
42305 LD A,(HL) Return if that slot is already in use.
42306 AND A
42307 RET NZ
42308 LD (HL),200 Write type 200.
42310 INC HL Move onto the new world X.
42311 INC HL
42312 EX DE,HL Switch the destination into DE.
Select a speed and thrust pair from Handler_PlayerShot_Table for the new slot.
42313 LD A,(24130) Fetch GameTimer.
42316 LD C,A Stash it in C.
42317 LD A,(24128) Fetch RandomNumber.
42320 ADD A,C Add the timer.
42321 LD (24128),A Write it back to RandomNumber.
Use bits 2-5 of the timer to index the table.
42324 LD A,(24128) Fetch RandomNumber.
42327 AND %00111100 Keep only bits 2-5.
42329 LD C,A Create an offset in BC.
42330 LD B,0
42332 LD HL,42635 HL=Handler_PlayerShot_Table.
42335 ADD HL,BC Add the offset.
42336 INC HL Skip the X and Y offsets to reach the speed in the table.
42337 INC HL
Place the new object beside and above this one.
42338 LD A,(IX+2) Fetch the actor world X.
42341 ADD A,8 Add 8.
42343 LD (DE),A Write it as the new world X.
Carry the addition into the high byte of the new world X.
42344 INC DE Move onto the high byte.
42345 LD A,(IX+3) Fetch the actor world X high byte.
42348 ADC A,0 Add the carry.
42350 AND %00011111 Keep only bits 0-4.
42352 LD (DE),A Write the high byte.
Put the new Y 16 above the actor Y.
42353 INC DE Move onto the new Y.
42354 LD A,(IX+4) Fetch the actor Y.
42357 SUB 16 Subtract 16.
42359 JR Handler_PlayerShot_WriteFields Jump to Handler_PlayerShot_WriteFields.
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