jetpac: Routine at 687a

687a: Animates the explosion sprites.

Input
IX	Explosion animation object

687a

ld hl,$5dcb

Increment current alien number

687d

inc (hl)

687e

ld c,(ix+$04)

C=explosion animation frame

6881

ld b,(ix+$05)

B=explosion animation state

6884

ld a,($5dcc)

Game timer

6887

and b

6888

jr nz,$688d

Increment frame if timer&state is zero

688a

inc (ix+$04)

688d

ld a,c

A=original frame count

688e

sla c

Multiply by 2 (addresses are two-bytes)

6890

ld b,$00

6892

ld hl,$68d8

HL=explosion sprite lookup table

6895

add hl,bc

Set offset

6896

ld e,(hl)

DE=address of the desired sprite

6897

inc hl

6898

ld d,(hl)

6899

ld l,(ix+$01)

Set HL to Y,X coords of sprite

689c

ld h,(ix+$02)

689f

cp $06

Comparing with original frame count from 687e

68a1

jr nc,$68b7

If original frame >= 6 then animation has finished

68a3

cp $03

68a5

jr nc,$68d2

If original frame >= 3 then half animated

68a7

call $7263

Erase animation sprite

68aa

ld a,($5dce)

A=random number

68ad

and $07

68af

or $42

68b1

ld (ix+$03),a

Update colour attribute to a random colour

68b4

Colourize the sprite

After an explosion, we check if it was the player that died!

68b7

ld a,(ix+$06)

Update anim object so "animating" = "direction"?

68ba

ld (ix+$00),a

68bd

call $72ef

Update Actor position direction

68c0

call $726d

Find and destroy actor

68c3

ld (ix+$00),$00

Reset "animating"

68c7

ld a,(ix+$06)

Animation object "direction"

68ca

and $3f

68cc

cp $03

68ce

jp c,$60b7

Player was killed if < 3 (end of turn)

68d1

ret

Called when half the explosion has been animated.

68d2

call $71f2

Get sprite screen position

68d5

Erase a destroyed actor