Lunar Jetman: Routine at B33D

B33D: Tick Actor Frame

Decrease *IX+12, apply speed, and redraw the actor.

Input
IX	Actor slot

Reload the frame timer, or apply speed and redraw.

TickActorFrame

B33D

DEC (IX+$12)

Jump to TickActorFrame_ApplyMotion if the frame timer is not zero.

B340

JR NZ,TickActorFrame_ApplyMotion

B342

LD A,(IX+$13)

Fetch *IX+13.

B345

LD (IX+$12),A

Reload the frame timer.

B348

INC (IX+$06)

Increase the actor thrust by one.

B34B

LD A,(IX+$05)

Fetch the actor speed.

B34E

AND A

Jump to TickActorFrame_ApplyMotion if the speed is zero.

B34F

JR Z,TickActorFrame_ApplyMotion

B351

JP P,TickActorFrame_DecreaseSpeed

Jump to TickActorFrame_DecreaseSpeed if the speed is positive.

B354

INC A

Increase the speed by two.

B355

INC A

TickActorFrame_DecreaseSpeed

B356

DEC A

Decrease the speed by one.

Apply the speed, then drop the actor by its thrust.

TickActorFrame_ApplyMotion

B357

CALL ApplyJetmanSpeed

Call ApplyJetmanSpeed.

B35A

LD A,(IX+$04)

Fetch the actor Y.

B35D

ADD A,(IX+$06)

Add the thrust.

B360

CP $AF

Jump to ExplodeAtGround if the actor has reached the ground line.

B362

JR NC,ExplodeAtGround

B364

LD (IX+$04),A

Write the new Y.

B367

LD C,A

Stash it in C.

B368

LD D,$03

D=03.

B36A

CALL SquareWave_Loop

Call SquareWave_Loop.

Pick the dying frame from the frame counter and redraw.

B36D

LD A,($5E42)

Fetch GameTimer.

B370

RRCA

Rotate it right once.

B371

AND %00000011

Keep only bits 0-1.

Sprite IDs begin at DC ("Jetman: Falling Frame 1").

B373

ADD A,$DC

Add DC for the dying frames.

B375

LD (IX+$00),A

Write it to the actor type.

B378

JP DrawCurrentActor_Draw

Jump to DrawCurrentActor_Draw.