dos33fsprogs/games/lemm/move_lemming.s
2022-03-24 00:21:50 -04:00

393 lines
5.5 KiB
ArmAsm

; TODO: auto-size this based on MAX_LEMMINGS
lemming_x:
.byte 0,0,0,0,0,0,0,0,0,0
lemming_y:
.byte 0,0,0,0,0,0,0,0,0,0
lemming_direction:
.byte 0,0,0,0,0,0,0,0,0,0
lemming_out:
.byte 0,0,0,0,0,0,0,0,0,0
lemming_frame:
.byte 0,0,0,0,0,0,0,0,0,0
lemming_status:
.byte 0,0,0,0,0,0,0,0,0,0
lemming_exploding:
.byte 0,0,0,0,0,0,0,0,0,0
lemming_fall_distance:
.byte 0,0,0,0,0,0,0,0,0,0
;==========================
; move them
;==========================
move_lemmings:
ldy #0
sty CURRENT_LEMMING
move_lemming_loop:
ldy CURRENT_LEMMING
lda lemming_out,Y
bne really_move_lemming
jmp done_checking_lemming
really_move_lemming:
; bump frame
tya
tax
inc lemming_frame,X ; only can inc with X
lda lemming_status,Y
cmp #LEMMING_FALLING
beq do_lemming_falling
cmp #LEMMING_WALKING
beq do_lemming_walking
cmp #LEMMING_DIGGING
beq do_lemming_digging
jmp done_move_lemming
;=========================
; falling
;=========================
do_lemming_falling:
tya
tax
inc lemming_y,X ; fall speed
inc lemming_y,X
inc lemming_fall_distance,X ; how far
jsr collision_check_ground
jmp done_move_lemming
;=========================
; walking
;=========================
do_lemming_walking:
; see if ground has risen up
jsr collision_check_hill
; collision detect walls
ldy CURRENT_LEMMING
lda lemming_y,Y
clc
adc #3 ; waist-high?
tax
lda hposn_high,X
clc
adc #$20
sta GBASH
lda hposn_low,X
sta GBASL
; increment
; only do this every 4th frame?
lda lemming_frame,Y
and #$3
beq walking_increment
bne walking_done
walking_increment:
; actually incrememt
clc ; increment/decrement X
lda lemming_x,Y
adc lemming_direction,Y ; A is now incremented version
; sta lemming_x,Y
tay ; Y is now incremented version
lda (GBASL),Y ; collision check
and #$7f
beq walking_no_wall
walking_yes_wall:
; we hit a wall, reverse course, undo the increment
; Y is updated
jsr check_at_exit_xiny
; reverse direction
ldy CURRENT_LEMMING
lda lemming_direction,Y
eor #$ff
clc
adc #1
sta lemming_direction,Y
jmp walking_no_increment
walking_no_wall:
; y is incremented version
tya
ldy CURRENT_LEMMING
sta lemming_x,Y
walking_no_increment:
jsr collision_check_ground
walking_done:
jmp done_move_lemming
;=====================
; digging
;=====================
do_lemming_digging:
lda lemming_y,Y
clc
adc #9
tax
lda hposn_high,X
clc
adc #$20
sta GBASH
lda hposn_low,X
sta GBASL
lda lemming_x,Y
tay
lda (GBASL),Y
and #$7f
beq digging_falling
digging_digging:
lda #$0
sta (GBASL),Y
; lda GBASH
; clc
; adc #$20 ; erase bg
; sta GBASH
; lda #$0
; sta (GBASL),Y
ldx CURRENT_LEMMING
inc lemming_y,X
jmp done_digging
digging_falling:
ldy CURRENT_LEMMING
lda #LEMMING_FALLING
sta lemming_status,Y
done_digging:
done_move_lemming:
done_checking_lemming:
inc CURRENT_LEMMING
lda CURRENT_LEMMING
cmp #MAX_LEMMINGS
beq really_done_checking_lemming
jmp move_lemming_loop
really_done_checking_lemming:
rts
;==========================
; remove lemming from game
;==========================
; Y points to CURRENT_LEMMING
; if C set it means they exited
remove_lemming:
bcc didnt_exit
sed
lda PERCENT_RESCUED_L
clc
adc PERCENT_ADD
sta PERCENT_RESCUED_L
bcc no_percent_oflo
inc PERCENT_RESCUED_H
no_percent_oflo:
cld
jsr update_percent_in
didnt_exit:
sed ; decrement BCD value
lda LEMMINGS_OUT
sec
sbc #1
sta LEMMINGS_OUT
cld
jsr click_speaker
lda #0
ldy CURRENT_LEMMING
sta lemming_out,Y
jsr update_lemmings_out
; if that was the last one, then level over
lda LEMMINGS_OUT
bne not_last_lemming
lda #LEVEL_WIN
sta LEVEL_OVER
not_last_lemming:
rts
;=============================
; collision check ground
;=============================
collision_check_ground:
lda lemming_y,Y
clc
adc #9
tax
lda hposn_high,X
clc
adc #$20 ; check bg, not fg
sta GBASH
lda hposn_low,X
sta GBASL
lda lemming_x,Y
tay
lda (GBASL),Y
and #$7f
beq ground_falling ; if empty space below us, fall
ground_walking:
; hit ground walking
ldy CURRENT_LEMMING
lda lemming_fall_distance,Y
cmp #32
bcs lemming_goes_splat
lda #0
sta lemming_fall_distance,Y
lda #LEMMING_WALKING ; else, walk
jmp done_check_ground
ground_falling:
lda #LEMMING_FALLING
done_check_ground:
ldy CURRENT_LEMMING
sta lemming_status,Y
rts
lemming_goes_splat:
lda #LEMMING_SPLATTING
sta lemming_status,Y
lda #0
sta lemming_frame,Y
; clc
; jsr remove_lemming
rts
;=============================
; collision check hill
;=============================
collision_check_hill:
lda lemming_y,Y
clc
adc #8
tax
lda hposn_high,X
clc
adc #$20 ; check bg, not fg
sta GBASH
lda hposn_low,X
sta GBASL
lda lemming_x,Y
tay
lda (GBASL),Y
and #$7f
beq on_ground ; if empty space below us, good
underground:
ldx CURRENT_LEMMING
dec lemming_y,X ; bump us up
on_ground:
rts
;=============================
; check at exit
;=============================
check_at_exit_xiny:
tya
ldy CURRENT_LEMMING
jmp check_at_exit_y
check_at_exit:
; see if at exit
ldy CURRENT_LEMMING
; check X
lda lemming_x,Y
check_at_exit_y:
exit_x1_smc:
cmp #31
bcc not_done_level
exit_x2_smc:
cmp #35
bcs not_done_level
; check Y
lda lemming_y,Y
exit_y1_smc:
cmp #116
bcc not_done_level
exit_y2_smc:
cmp #127
bcs not_done_level
; done level
sec
jsr remove_lemming
not_done_level:
rts