Dynamite Dan: Routine at D2BF

D2BF: Remove an object that Dan collided with from the room.

Used by the routine at D1CE.

Input
A	Count of objects in the room
BC	Pointer to the moving graphics buffer
IY	Pointer to moving objects data in the room

D2BF

AND A

Are there any objects left?

D2C0

RET Z

Return if there aren't.

D2C1

LD L,A

Put the object count in HL.

D2C2

LD A,($D1CD)

Get the collision attribute (D1CD).

D2C5

CP (IY+$05)

Does it equal this one?

D2C8

JR NZ,$D2D5

Move forward if it doesn't.

The attribute matches the one collided with, now check the position.

D2CA

LD E,(IY+$00)

Put the co-ordinates in DE.

D2CD

LD D,(IY+$01)

D2D0

CALL $DB38

Has Dan collided with it?

D2D3

JR C,$D2DE

Yes, so remove it.

D2D5

LD DE,$0008

Otherwise, move to the next object.

D2D8

ADD IY,DE

D2DA

DEC L

Decrement the object count.

D2DB

JR NZ,$D2C2

Loop until we've looked at all objects.

D2DD

RET

Found the object Dan collided with, so remove it.

D2DE

LD D,(IY+$01)

Put the position of the object in DE.

D2E1

LD A,(IY+$00)

D2E4

ADD A,C

D2E5

DEC A

D2E6

LD E,A

D2E7

SET 6,(IY+$04)

Set the "object removed" flag.

D2EB

CALL $E897

Remove the object from screen.

D2EE

POP HL

Clear the stack, so return won't pass to the calling routine (D1CE) but to the routine above that ie: do an early return. (For homework, look up "tail call optimisation").

D2EF

RET