###########################################
#
#  Deep8
#
#  A stripped down port of the Mako game
#  "Deep" for Chip8.
#  Move your boat left and right with A/D
#  Press S to drop a bomb and release S
#  to detonate it. Destroy incoming
#  squid before they tip your boat!
#
#  This game was one of the earliest
#  programs written using Octo.
#
###########################################

: waves
	0b00110011
	0b11101110

: boat
	0b00000100
	0b00000100
	0b11111111
	0b11111111
	0b01111101

: boat-flip
	0b00000000
	0b00000000
	0b01111101
	0b11111111
	0b11111111

: bomb
	0b00001000
	0b00010100
	0b00010000
	0b00111000
	0b00111000
	0b00111000

: fall
	0b01000000
	0b01010000
	0b01100000
	0b11110000
	0b01100000
	0b01000000

: squid-0
	0b00111100
	0b00111100
	0b01011010
	0b01011010

: squid-1
	0b00111100
	0b00111100
	0b11011011
	0b00100100

: boom
	0b10010000
	0b00010010
	0b01100000
	0b00000000
	0b10000011
	0b00100100
	0b00100001

: title-0
	0b00010000
	0b00010000
	0b00010000
	0b00010000
	0b01110000
	0b10010000
	0b10010000
	0b10010000
	0b10010000
	0b01110000
: title-1
	0b01100000
	0b10010000
	0b11110000
	0b10000000
	0b10000000
	0b01110000
: title-2
	0b11100000
	0b10010000
	0b10010000
	0b10010000
	0b10010000
	0b11100010
	0b10000000
	0b10000000
	0b10000000
	0b10000000

: end-0
	0b11101010
	0b01001110
	0b01001010
	0b01001010
: end-1
	0b11100111
	0b11000110
	0b10000100
	0b11100111
: end-2
	0b01100110
	0b01010101
	0b01010101
	0b01010110

# register scratchpad:
: scratch      0 0 0 0

# storage for BCD decoding:
: score-digits 0 0 0

# enemy data:
: e1  1 0 0
: e2 20 0 0
: e3 40 0 0
: e4 90 0 0

###########################################
#
#  Introduction
#
###########################################

: draw-waves
	i  := waves
	v0 := 0 # x
	v1 := 7 # y
	loop
		sprite v0 v1 2
		v0 += 8
		while v0 != 64
	again
;

: title
	draw-waves
	i  := title-0
	v0 := 16
	v1 := 12
	sprite v0 v1 10
	i  := title-1
	v0 +=  8
	v1 +=  4
	sprite v0 v1  6
	v0 +=  8
	sprite v0 v1  6
	i  := title-2
	v0 +=  8
	sprite v0 v1 10
	v0 := key
;

: draw-score
	i := score-digits
	load v2
	i  := hex v0
	v0 := 49
	v3 :=  1
	sprite v0 v3 5
	i  := hex v1
	v0 += 5
	sprite v0 v3 5
	i  := hex v2
	v0 += 5
	sprite v0 v3 5
;

: inc-score
	i := scratch
	save v3
	draw-score
	v9 += 1
	i := score-digits
	bcd v9
	draw-score
	i := scratch
	load v3
;

: init-game
	clear
	draw-waves
	v8 :=  0    # enemy  tick timer
	v9 :=  0    # player score
	va := 32    # player horizontal position
	vb :=  1    # player vertical   position
	vc := 10    # bomb   horizontal position
	vd := 10    # bomb   vertical   position
	ve :=  0    # bomb   state (0=invisible, 1=falling, 2+=exploding)

	# draw initial boat
	i  := boat
	sprite va vb 5

	# draw initial score
	draw-score
;

###########################################
#
#  Game Over
#
###########################################

: delay-loop
	v0 := 0
	loop
		v0 += 1
		while v0 != 32
	again 
;

: game-over
	# erase player
	i  := boat
	sprite va vb 5
	
	# flip boat
	i  := boat-flip
	sprite va vb 5

	# animate the player sinking
	i  := fall
	vb := 8
	sprite va vb 6
	loop
		delay-loop
		sprite va vb 6
		vb += 1
		sprite va vb 6
		while vb != 26
	again
	sprite va vb 6
	
	# show 'the end'
	va := 20
	vb := 14
	i  := end-0
	sprite va vb 4
	i  := end-1
	va += 8
	sprite va vb 4
	i  := end-2
	va += 8
	sprite va vb 4

	loop again

###########################################
#
#  Enemy Logic
#
###########################################

# v0 - enemy timer. (0=swim, >0=time until next spawn)
# v1 - horizontal position
# v2 - vertical   position

: enemy-sprite
	v4 := 1
	v4 &= v2
	i  := squid-0
	if v4 == 1 then i := squid-1
;

: spawn-enemy
	v1 := random 63
	v2 := 28
	enemy-sprite
	sprite v1 v2 4
;

: count-enemy
	v0 -= v3
	if v0 == 0 then spawn-enemy
;

: update-enemy
	if v0 != 0 then jump count-enemy
	enemy-sprite
	sprite v1 v2 4
	v2 -= v3

	# kill the player if
	# an enemy reaches the surface:
	if v2 == 8 then jump game-over

	enemy-sprite
	sprite v1 v2 4

	# die on collision:
	if vf == 0 then return
	sprite v1 v2 4
	v0 := random 31
	v0 += 10
	inc-score
;

: update-enemies
	v3 := 1
	v8 ^= v3
	if v8 == 0 then return
	i := e1 load v2 update-enemy i := e1 save v2
	i := e2 load v2 update-enemy i := e2 save v2
	i := e3 load v2 update-enemy i := e3 save v2
	i := e4 load v2 update-enemy i := e4 save v2
;

###########################################
#
#  Player/Bomb Logic
#
###########################################

: bomb-fire
	if ve != 0 then return
	vc := va
	vd := 10
	ve := 1
	i  := bomb
	sprite vc vd 6
;

: update-player
	v2 := 3
	v1 := va
	v0 := 7
	if v0 key then va -= v2
	v0 := 9
	if v0 key then va += v2
	v0 := 8
	if v0 key then bomb-fire
	if v1 == va then return
	i := boat
	sprite v1 vb 5
	sprite va vb 5
;

: bomb-explode
	ve := 2
	i  := boom
	sprite vc vd 7
;

: bomb-falling
	i  := bomb
	sprite vc vd 6
	vd += 1
	if vd == 25 then jump bomb-explode
	v0 := 8
	if v0 -key then  jump bomb-explode
	sprite vc vd 6
;

: bomb-exploding
	ve += 1
	if ve != 4 then return
	ve := 0
	i  := boom
	sprite vc vd 7
;

: update-bomb
	if ve == 1 then jump bomb-falling
	if ve != 0 then jump bomb-exploding
;

###########################################
#
#  Main Loop
#
###########################################

: main
	title
	init-game
	loop
		update-player
		update-bomb
		update-enemies
	again