dos33fsprogs/demos/another_myst/keyboard.s

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2020-06-20 22:29:00 +00:00
;======================================
; handle keypress
;======================================
; A or <- : start moving left
; D or -> : start moving right
; W or up : jump or elevator/transporter up
; S or down : crouch or pickup or elevator/transporter down
; L : charge gun
; space : action
; escape : quit
; if left: if running right, walk right
; if walk right, stand right
; if stand right, stand left
; if stand left, walk left
; if walk left, run left
; if up: if crouching, stand up
; if standing, jump
; if walking, jump
; if running, run-jump
; if down: if standing, crouch
; if walking, crouch
; if if running, slide-crouch
handle_keypress:
lda PHYSICIST_STATE
bmi no_keypress ; ignore keypress if dying/action
lda KEYPRESS ; 4
bmi keypress ; 3
no_keypress:
bit KEYRESET ; clear
; avoid keeping old keys around
rts ; nothing pressed, return
keypress:
; -1
and #$7f ; clear high bit
;======================
; check escape
check_quit:
cmp #27 ; quit if ESCAPE pressed
bne check_left
;=====================
; QUIT
;=====================
quit:
lda #$ff ; could just dec
sta GAME_OVER
rts
;======================
; check left
check_left:
cmp #'A'
beq left_pressed
cmp #$8 ; left arrow
bne check_right
;====================
;====================
; Left/A Pressed
;====================
;====================
left_pressed:
inc GUN_FIRE ; fire gun if charging
; left==0
lda DIRECTION ; if facing right, turn to face left
bne left_going_right
left_going_left:
lda PHYSICIST_STATE
cmp #P_STANDING
beq walk_left
cmp #P_SHOOTING
beq walk_left
cmp #P_WALKING
beq run_left
and #STATE_CROUCHING
bne stand_left
;=============================
; already running, do nothing?
jmp done_keypress
left_going_right:
lda PHYSICIST_STATE
cmp #P_RUNNING
beq walk_right
cmp #P_WALKING
beq stand_right
cmp #P_STANDING
beq stand_left
cmp #P_SHOOTING
beq stand_left
and #STATE_CROUCHING
bne stand_left
;===========================
; otherwise?
jmp done_keypress
;========================
; check for right pressed
check_right:
cmp #'D'
beq right_pressed
cmp #$15
bne check_up
;===================
;===================
; Right/D Pressed
;===================
;===================
right_pressed:
inc GUN_FIRE ; fire if charging
; right==1
lda DIRECTION ; if facing left, turn to face right
beq right_going_left
right_going_right:
lda PHYSICIST_STATE
cmp #P_STANDING
beq walk_right
cmp #P_SHOOTING
beq walk_right
cmp #P_WALKING
beq run_right
and #STATE_CROUCHING
bne stand_right
;=============================
; already running, do nothing?
jmp done_keypress
right_going_left:
lda PHYSICIST_STATE
cmp #P_RUNNING
beq walk_left
cmp #P_WALKING
beq stand_left
cmp #P_STANDING
beq stand_right
cmp #P_SHOOTING
beq stand_right
and #STATE_CROUCHING
bne stand_right
;===========================
; otherwise?
jmp done_keypress
;=====================
; Left, direction=0
; Right, direction=1
stand_left:
lda #0 ; left
sta DIRECTION
sta GAIT
lda #P_STANDING
beq update_state
walk_left:
lda #P_WALKING
bne update_state
run_left:
lda #P_RUNNING
bne update_state
stand_right:
lda #0
sta GAIT
lda #1 ; just inc DIRECTION?
sta DIRECTION
lda #P_STANDING
beq update_state
walk_right:
lda #P_WALKING
bne update_state
run_right:
lda #P_RUNNING
bne update_state
update_state:
sta PHYSICIST_STATE
jmp done_keypress
;=====================
; check up
check_up:
cmp #'W'
beq up
cmp #$0B
bne check_down
up:
;=============================
;=============================
; Up/W Pressed -- Jump, Get up
;=============================
;=============================
lda PHYSICIST_STATE ; shoot if charging
cmp #P_CROUCH_SHOOTING
beq up_no_fire
inc GUN_FIRE
up_no_fire:
lda ON_ELEVATOR
beq up_not_elevator
up_on_elevator:
lda #P_ELEVATING_UP
jmp change_state_clear_gait
up_not_elevator:
lda PHYSICIST_STATE
cmp #P_CROUCHING
beq stand_up
cmp #P_CROUCH_SHOOTING
beq stand_up_shoot
cmp #P_RUNNING
beq run_jump
up_jump:
lda #P_JUMPING
jmp change_state_clear_gait
run_jump:
lda #P_JUMPING|STATE_RUNNING
jmp change_state_clear_gait
stand_up:
lda #P_STANDING
jmp change_state_clear_gait
stand_up_shoot:
lda #P_SHOOTING
jmp change_state_clear_gait
;==========================
check_down:
cmp #'S'
beq down
cmp #$0A
bne check_gun
;==========================
;==========================
; Down/S Pressed -- Crouch
;==========================
;==========================
down:
lda PHYSICIST_STATE ; shoot if charging
cmp #P_SHOOTING
beq down_no_fire
inc GUN_FIRE
down_no_fire:
lda ON_ELEVATOR
beq down_not_elevator
down_on_elevator:
lda #P_ELEVATING_DOWN
jmp change_state_clear_gait
down_not_elevator:
lda PHYSICIST_STATE
cmp #P_SHOOTING
bne start_crouch
start_crouch_shoot:
and #STATE_RUNNING
ora #P_CROUCH_SHOOTING
jmp change_state_clear_gait
start_crouch:
and #STATE_RUNNING
beq start_crouch_norun
ldx #4 ; slide a bit
stx GAIT
ora #P_CROUCHING
sta PHYSICIST_STATE
jmp done_keypress
start_crouch_norun:
ora #P_CROUCHING
jmp change_state_clear_gait
;==========================
check_gun:
cmp #'L'
bne check_space
;======================
; 'L' to charge gun
;======================
charge_gun:
lda HAVE_GUN ; only if have gun
beq done_keypress
lda GUN_STATE
beq not_already_firing
inc GUN_FIRE ; if charging, fire
jmp done_keypress
not_already_firing:
inc GUN_STATE
lda PHYSICIST_STATE
and #STATE_CROUCHING
beq crouch_charge
ldy #P_CROUCH_SHOOTING
bne crouch_charge_go ; bra
crouch_charge:
ldy #P_SHOOTING
crouch_charge_go:
sty PHYSICIST_STATE
jmp shoot
check_space:
cmp #' '
beq space
; cmp #$15 ; ascii 21=??
jmp unknown
;======================
; SPACE -- Kick or shoot
;======================
space:
lda HAVE_GUN
beq kick
; shoot pressed
inc GUN_FIRE ; if charging, shoot
shoot:
lda PHYSICIST_STATE ; if in stance, then shoot
cmp #P_SHOOTING
beq in_position
cmp #P_CROUCH_SHOOTING
bne no_stance
in_position:
lda #1
sta LASER_OUT
jmp done_keypress
no_stance:
and #STATE_CROUCHING
beq stand_stance
crouch_stance:
lda #P_CROUCH_SHOOTING
jmp change_state_clear_gait
stand_stance:
lda #P_SHOOTING
jmp change_state_clear_gait
kick:
bit PHYSICIST_STATE ; crouching state in V now
bvc kick_standing
lda #P_CROUCH_KICKING
jmp kick_final
kick_standing:
lda #P_KICKING
kick_final:
sta PHYSICIST_STATE
lda #15
sta GAIT
unknown:
done_keypress:
bit KEYRESET ; clear the keyboard strobe ; 4
rts ; 6
change_state_clear_gait:
sta PHYSICIST_STATE
lda #0
sta GAIT
jmp done_keypress