Krakout: Register a brick hit

A99B: Register a brick hit

Resolves a hit on a brick: it classifies the tile's durability and queues the break animation the brick-field sweep plays.

Input
HL	tile-map address of the struck brick

hit_brick

A99B

LD A,L

Align the struck brick's tile-map address and save it for the rest of the hit.

A99C

AND $DE

A99E

LD L,A

A99F

LD (hit_brick_addr),HL

A9A2

LD A,(bat_side)

Pick the brick field's first cell in the tile map. With the bat on the right, the field starts at column 2.

A9A5

OR A

A9A6

JR NZ,hit_brick_left_bat

A9A8

LD DE,TILEMAP_BASE+$82

A9AB

JR hit_brick_calc_index

hit_brick_left_bat

A9AD

LD DE,TILEMAP_BASE+$8C

With the bat on the left, the field starts at column 12.

hit_brick_calc_index

A9B0

AND A

Convert the brick's tile-map position into its offset in the brick state map, the brick index doubled.

A9B1

SBC HL,DE

A9B3

LD A,L

A9B4

AND $1F

A9B6

SRL A

A9B8

SRL H

A9BA

RR L

A9BC

SRL H

A9BE

RR L

A9C0

SRL L

A9C2

SRL L

A9C4

SRL L

A9C6

SRL L

A9C8

LD B,L

hit_brick_row_loop

A9C9

ADD A,$09

A9CB

DJNZ hit_brick_row_loop

A9CD

ADD A,A

A9CE

LD (hit_brick_index),A

Save the brick's state-map offset.

A9D1

LD A,(hit_params)

Branch on what struck the brick. A ball goes to the missile-shot test, and the starburst clears the brick outright. An inhabitant goes to the durability check.

A9D4

OR A

A9D5

JR Z,hit_brick_normal_path

A9D7

CP $02

A9D9

JR Z,hit_brick_mark

A9DB

JP hit_brick_classify

hit_brick_normal_path

A9DE

LD A,(active_ball)

A ball hit: only the secondary object that carries the missile shot force-clears the brick, and it sounds its own break note first. Ball A and a real ball B jump to the classifier.

A9E1

OR A

A9E2

JR Z,hit_brick_classify

A9E4

LD A,(missile_shot)

A9E7

OR A

A9E8

JR Z,hit_brick_classify

A9EA

CALL sfx_brick_hit

hit_brick_mark

A9ED

LD A,(hit_brick_index)

Queue the plain shatter in the brick's state map entry, from sub-frame zero, and score the combo. No durability check runs, so any tile empties, the golden brick included.

A9F0

LD E,A

A9F1

LD D,$00

A9F3

LD HL,brick_state_map

A9F6

ADD HL,DE

A9F7

LD (HL),$01

A9F9

INC HL

A9FA

LD (HL),$00

A9FC

CALL score_brick

A9FF

RET

hit_brick_classify

AA00

LD HL,(hit_brick_addr)

Walk the durability table from its first class with the struck brick's tile in hand.

AA03

LD DE,brick_durability_classes

AA06

LD C,$01

hit_brick_scan

AA08

LD A,(DE)

A terminator byte closes the class the counter is on.

AA09

CP $FF

AA0B

JR NZ,hit_brick_scan_match

AA0D

INC C

Bump the counter; run out of classes and the tile is unclassified, so the hit is dropped.

AA0E

LD A,C

AA0F

CP $13

AA11

RET Z

AA12

JR hit_brick_scan_next

Otherwise continue the scan.

hit_brick_scan_match

AA14

CP (HL)

A byte equal to the struck tile names its class.

AA15

JR Z,hit_brick_found

hit_brick_scan_next

AA17

INC DE

Step to the next tile code and continue the walk.

AA18

JP hit_brick_scan

hit_brick_found

AA1B

LD A,C

Only the prize classes reach the reveal roll.

AA1C

CP $07

AA1E

JR C,hit_brick_pick_sound

AA20

CP $10

Skip the finished markers too.

AA22

JR NC,hit_brick_pick_sound

AA24

LD A,(hit_params)

An inhabitant step reveals nothing.

AA27

OR A

AA28

JR NZ,hit_brick_shatter

AA2A

LD A,(ball_gem_frame)

While the ball gem is out, a prize that claims the secondary object cannot be revealed.

AA2D

OR A

AA2E

JR NZ,hit_brick_force_shatter

AA30

LD A,(ball_b_in_play)

The secondary object carries a ball while the missile shot or a real ball B is out. While it does, a prize that claims the secondary object cannot be revealed either.

AA33

OR A

AA34

JR Z,hit_brick_prize_roll

hit_brick_force_shatter

AA36

LD A,C

Force each prize that claims the secondary object down the plain path. This test is the bomb.

AA37

CP $08

AA39

JR Z,hit_brick_shatter

AA3B

CP $09

This one is the missile prize.

AA3D

JR Z,hit_brick_shatter

AA3F

CP $0B

This one is the double bat prize.

AA41

JR Z,hit_brick_shatter

hit_brick_prize_roll

AA43

CALL next_random

Prize-reveal 50/50 for a prize brick: the low bit of the latest random number. One outcome keeps the brick's own class, whose break animation ends on that class's prize glyph. A later hit takes the prize through the prize handler. The other falls through to the plain break animation, which shatters the slot empty.

AA46

AND $01

AA48

JR Z,hit_brick_pick_sound

hit_brick_shatter

AA4A

LD C,$01

The force paths land here: the brick takes the plain break sequence whatever its own class was.

hit_brick_pick_sound

AA4C

LD A,C

The resolved class picks the sound: the plain break path plays the brick-destroyed sound.

AA4D

CP $01

AA4F

JR NZ,hit_brick_chirp_sound

AA51

CALL sfx_brick_destroyed

AA54

JR hit_brick_queue_anim

hit_brick_chirp_sound

AA56

CP $06

The golden and silver brick classes play the brick-survives sound instead. The prize classes stay silent here and arm the tune below.

AA58

JR NC,hit_brick_arm_prize_tune

AA5A

CALL sfx_brick_survives

AA5D

JR hit_brick_queue_anim

hit_brick_arm_prize_tune

AA5F

LD A,$01

Reached when a struck brick's resolved durability class is a prize class. Arm the prize-reveal tune, then fall through to the break-animation queue, which queues the reveal sequence and scores the hit.

AA61

LD (prize_reveal_tune_gate),A

hit_brick_queue_anim

AA64

LD HL,brick_state_map

Queue the resolved class in the brick's state map entry, from sub-frame zero, so the brick-field sweep plays its break sequence.

AA67

LD A,(hit_brick_index)

AA6A

LD E,A

AA6B

LD D,$00