dos33fsprogs/demos/another_myst/gun.s

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2020-06-20 22:29:00 +00:00
;
; Gun behavior
;
; When 'L' pressed gun is charging
; we handle that here
;===================================
; handle/draw all gun related stuff
;===================================
handle_gun:
;===================
; check_gun_firing
;===================
jsr check_gun_firing
;=======================
; draw gun charge effect
;=======================
jsr draw_gun_charging
;================
; move laser
;================
jsr move_laser
;================
; draw laser
;================
jsr draw_laser
;================
; move blast
;================
jsr move_blast
;================
; draw blast
;================
jsr draw_blast
;================
; draw shields
;================
jmp draw_shields
; rts
;====================
;====================
; check gun firing
;====================
;====================
check_gun_firing:
lda HAVE_GUN ; no gun, do nothing
beq no_have_gun
;================
; fire laser
;================
lda LASER_OUT
beq no_fire_laser
jsr fire_laser
no_fire_laser:
lda #0
sta LASER_OUT
lda GUN_STATE ; gun not charging, do nothing
beq done_gun
lda GUN_FIRE ; if fired, fire it
bne fire_gun
; increment gun state
lda FRAMEL ; slow down
and #$7
bne done_inc_gun_state
inc GUN_STATE
; saturate
lda GUN_STATE
cmp #24
bne done_inc_gun_state
lda #21 ; wrap at end
sta GUN_STATE
done_inc_gun_state:
jmp done_gun
fire_gun:
; fire here
lda GUN_STATE
cmp #5
bcc done_gun ; too short, do nothing
cmp #21
bcs do_blast ; too long, blast
; shield
jsr activate_shield
jmp done_firing
do_blast:
jsr fire_blast
done_firing:
lda #0
sta GUN_STATE
done_gun:
no_have_gun:
lda #0
sta GUN_FIRE
rts
;============================
; draw gun charging effect
;============================
draw_gun_charging:
lda HAVE_GUN ; no gun, do nothing
beq done_draw_gun_charging
lda GUN_STATE ; gun not charging, do nothing
beq done_draw_gun_charging
; set direction
lda DIRECTION
bne zap_right
zap_left:
ldx PHYSICIST_X
dex
dex
stx XPOS
jmp done_zap
zap_right:
lda PHYSICIST_X
clc
adc #5
sta XPOS
done_zap:
lda PHYSICIST_Y
clc
adc #4
ldy PHYSICIST_STATE
cpy #P_CROUCH_SHOOTING
bne done_zap_ypos
clc
adc #4
done_zap_ypos:
sta YPOS
ldy GUN_STATE
lda gun_charge_progression,Y
tay
lda gun_charge_table_lo,Y
sta INL
lda gun_charge_table_hi,Y
sta INH
jsr put_sprite
done_draw_gun_charging:
rts
; progression
gun_charge_progression:
.byte 0,0,0,1,2,3
.byte 4,5,6,4,5,6,4,5,6,4,5,6,4,5,6 ; 20
.byte 7,8,9
gun_charge_table_lo:
.byte <gun_charge_sprite0
.byte <gun_charge_sprite1
.byte <gun_charge_sprite2
.byte <gun_charge_sprite3
.byte <gun_charge_sprite4
.byte <gun_charge_sprite5
.byte <gun_charge_sprite6
.byte <gun_charge_sprite7
.byte <gun_charge_sprite8
.byte <gun_charge_sprite9
gun_charge_table_hi:
.byte >gun_charge_sprite0
.byte >gun_charge_sprite1
.byte >gun_charge_sprite2
.byte >gun_charge_sprite3
.byte >gun_charge_sprite4
.byte >gun_charge_sprite5
.byte >gun_charge_sprite6
.byte >gun_charge_sprite7
.byte >gun_charge_sprite8
.byte >gun_charge_sprite9
; startup
gun_charge_sprite0:
.byte 2,2
.byte $AA,$AA
.byte $AA,$AA
gun_charge_sprite1:
.byte 2,2
.byte $fA,$AA
.byte $AA,$AA
gun_charge_sprite2:
.byte 2,2
.byte $22,$AA
.byte $AA,$AA
gun_charge_sprite3:
.byte 2,2
.byte $ef,$eA
.byte $fe,$Ae
; medium
gun_charge_sprite4:
.byte 2,2
.byte $ff,$AA
.byte $Ae,$AA
gun_charge_sprite5:
.byte 2,2
.byte $ef,$AA
.byte $Ae,$AA
gun_charge_sprite6:
.byte 2,2
.byte $ef,$AA
.byte $Af,$AA
; large
gun_charge_sprite7:
.byte 2,2
.byte $fe,$fe
.byte $Ae,$Ae
gun_charge_sprite8:
.byte 2,2
.byte $fe,$fe
.byte $ef,$ef
gun_charge_sprite9:
.byte 2,2
.byte $ff,$ff
.byte $Ae,$Ae