dos33fsprogs/games/keen/handle_laser.s

164 lines
2.0 KiB
ArmAsm

; draw/move laser
; o/~ carrying a laser, down the road that I must travel o/~
; o/~ carrying a laser, in the darkness of the night o/~
;====================
; move laser
;====================
move_laser:
lda LASER_OUT
beq done_move_laser
lda LASER_X
clc
adc LASER_DIRECTION
sta LASER_X
laser_check_tiles:
; collision detect with tiles
; laser location is roughly
; (y/4)*16 + (x/2) - 2
lda LASER_Y
lsr
lsr
asl
asl
asl
asl
sta LASER_TILE
lda LASER_X
lsr
clc
adc LASER_TILE
sec
sbc #2
sta LASER_TILE
ldx LASER_TILE
lda tilemap,X
cmp #ALLHARD_TILES
bcs destroy_laser
laser_check_enemies:
; collision detect with enemies
jsr laser_enemies
; detect if off screen
laser_check_right:
lda LASER_X
cmp #31
bcc laser_check_left ; not_too_far_right
bcs destroy_laser
laser_check_left:
cmp #6
bcs done_move_laser
bcc destroy_laser
destroy_laser:
lda #0
sta LASER_OUT
done_move_laser:
rts
;====================
; draw laser
;====================
draw_laser:
lda LASER_OUT
beq done_draw_laser
lda LASER_X
sta XPOS
lda LASER_Y
sta YPOS
; lda LASER_DIRECTION
lda #<laser_sideways_sprite
sta INL
lda #>laser_sideways_sprite
sta INH
jsr put_sprite_crop
done_draw_laser:
rts
laser_sideways_sprite:
.byte 4,1
; .byte $3A,$cA,$3A,$cA
.byte $A3,$Ac,$A3,$Ac
;=======================
; laser enemies
;=======================
; see if laser hits any enemies
laser_enemies:
ldy #0
laser_enemies_loop:
; see if out
lda enemy_data_out,Y
beq done_laser_enemy
; get local tilemap co-ord
sec
lda enemy_data_tilex,Y
sbc TILEMAP_X
sta TILE_TEMP
sec
lda enemy_data_tiley,Y
sbc TILEMAP_Y
asl
asl
asl
asl
clc
adc TILE_TEMP
cmp LASER_TILE
bne done_laser_enemy
; hit something
hit_something:
lda #0
sta LASER_OUT
sta FRAMEL
; sta enemy_data+ENEMY_DATA_OUT,Y
lda #1
sta enemy_data_exploding,Y
; jsr enemy_noise
; jsr inc_score_by_10
jmp exit_laser_enemy
done_laser_enemy:
tya
clc
adc #8
tay
cpy #(NUM_ENEMIES*8)
bne laser_enemies_loop
exit_laser_enemy:
rts