dos33fsprogs/fireworks/fw.s
2018-09-10 15:42:40 -04:00

632 lines
9.3 KiB
ArmAsm

;=======================================================================
; Based on BASIC program posted by FozzTexx, originally written in 1987
;=======================================================================
; State:
; 0: Launch Rocket
; 1: Move Rocket
; 2: Start Explosion
; 3: Continue Explosion
; Constants
NUMSTARS = 16
YSIZE = 160
XSIZE = 280
MARGIN = 24
; Zero page addresses
STATE = $EE
OFFSET = $EF
COLOR_GROUP = $F0
X_VELOCITY = $F1
Y_VELOCITY_H = $F2
Y_VELOCITY_L = $F3
MAX_STEPS = $F4
XPOS_H = $F5
XPOS_L = $F6
YPOS_H = $F7
YPOS_L = $F8
PEAK = $F9
CURRENT_STEP = $FA
Y_OLD = $FB
Y_OLDER = $FC
X_OLD = $FD
X_OLDER = $FE
TEMPY = $FF
draw_fireworks:
jsr HOME ; clear screen
jsr hgr ; set high-res, clear screen, page0
lda #0
sta STATE
jsr draw_stars ; draw the stars
fireworks_state_machine:
; see if key pressed
lda KEYPRESS ; check if keypressed
bmi done_fireworks ; if so, exit
lda STATE
cmp #0
bne s1
jsr launch_firework
jmp fireworks_state_machine
s1:
cmp #1
bne s2
jsr move_rocket
jmp fireworks_state_machine
s2:
cmp #2
bne s3
jsr start_explosion
jmp fireworks_state_machine
s3:
jsr continue_explosion
jmp fireworks_state_machine
done_fireworks:
rts
;===========================
; LAUNCH_FIREWORK
;===========================
; cycles=???
launch_firework:
jsr random16 ; 6+42
lda SEEDL ; 3
and #$4 ; 2
sta COLOR_GROUP ; HGR color group (0 PG or 4 BO) ; 4
jsr random16 ; 6+42
lda SEEDL ; 3
and #$3 ; 2
clc ; 2
adc #$1 ; 2
sta X_VELOCITY ; x velocity = 1..4 ; 3
jsr random16 ; 6+42
lda SEEDL ; 3
and #$3 ; 2
clc ; 2
adc #$2 ; 2
eor #$ff ; 2
sta Y_VELOCITY_H ; y velocity = -3..-6 ; 3
lda #0 ; 2
sta Y_VELOCITY_L ; it's 8:8 fixed point ; 3
jsr random16 ; 6+42
lda SEEDL ; 3
and #$1f ; 2
clc ; 2
adc #33 ; 2
sta MAX_STEPS ; 33..64 ; 3
; launch from the two hills
jsr random16 ; 6+42
lda SEEDL ; 3
and #$3f ; 2
sta XPOS_L ; 3
jsr random16 ; 6+42
lda SEEDL ; 3
and #$1 ; 2
beq right_hill ; 2
left_hill:
lda XPOS_L ; 3
clc ; 2
adc #24 ; 2
sta XPOS_L ; 24-88 (64) ; 3
jmp done_hill ; 3
right_hill:
; 1
lda XPOS_L ; 3
clc ; 2
adc #191 ; 2
sta XPOS_L ; 191-255 (64) ; 3
lda X_VELOCITY ; 3
eor #$ff ; 2
sta X_VELOCITY ; 3
inc X_VELOCITY ; aim toward middle ; 5
done_hill:
lda #YSIZE ; 2
sta YPOS_H ; 3
lda #0 ; fixed point 8:8 ; 2
sta YPOS_L ; start at ground ; 3
lda YPOS_H ; 3
sta PEAK ; peak starts at ground ; 3
lda #1 ; 2
sta CURRENT_STEP ; 3
lda #1 ; 2
sta STATE ; move to launch ; 3
rts ; 6
;===============
; Move rocket
;===============
; cycles=???
move_rocket:
lda Y_OLD
sta Y_OLDER
lda YPOS_H
sta Y_OLD
lda X_OLD
sta X_OLDER
lda XPOS_L
sta X_OLD
; Move rocket
lda XPOS_L
clc
adc X_VELOCITY
sta XPOS_L ; adjust xpos
; 16 bit add
clc
lda YPOS_L
adc Y_VELOCITY_L
sta YPOS_L
lda YPOS_H
adc Y_VELOCITY_H
sta YPOS_H ; adjust ypos
; adjust Y velocity, slow it down
clc
lda Y_VELOCITY_L
adc #$20 ; $20 = 0.125
sta Y_VELOCITY_L
lda Y_VELOCITY_H
adc #0
sta Y_VELOCITY_H
; if we went higher, adjust peak
lda YPOS_H
cmp PEAK
bmi no_peak
sta PEAK
no_peak:
;========================================
; Check if out of bounds and stop moving
;========================================
lda XPOS_L ; if (xpos_l<=margin) too far left
cmp #MARGIN
bcc done_moving
; Due to 256 wraparound, the above will catch this case???
; cmp #XSIZE-MARGIN ; if (xpos_l>=(xsize-margin)) too far right
; bcs done_moving
lda YPOS_H ; if (ypos_h<=margin) too far up
cmp #MARGIN
bcc done_moving
;======================
; if falling downward
;======================
lda Y_VELOCITY_H
bmi going_up ; if (y_velocity_h>0)
; if too close to ground, explode
lda YPOS_H ; if (ypos_h>=ysize-margin)
cmp #(YSIZE-MARGIN)
bcs done_moving
; if fallen a bit past peak, explode
sec ; if (ypos_h>ysize-(ysize-peak)/2)
lda #YSIZE
sbc PEAK
lsr
eor #$FF
clc
adc #1
clc
adc #YSIZE
cmp YPOS_H
bcc done_moving
going_up:
jmp done_bounds_checking
done_moving:
lda MAX_STEPS
sta CURRENT_STEP
done_bounds_checking:
;==========================
; if not done, draw rocket
;==========================
lda CURRENT_STEP
cmp MAX_STEPS
beq erase_rocket
draw_rocket:
; set hcolor to proper white (3 or 7)
clc
lda COLOR_GROUP
adc #3
tax
lda colortbl,X ; get color from table
sta HGR_COLOR
; HPLOT X,Y: X= (y,x), Y=a
ldx X_OLD
lda Y_OLD
ldy #0
jsr hplot0 ; hplot(x_old,y_old);
; HPLOT to X,Y X=(x,a), y=Y
lda XPOS_L
ldx #0
ldy YPOS_H
jsr hglin ; hplot_to(xpos_l,ypos_h);
erase_rocket:
; erase with proper color black (0 or 4)
ldx COLOR_GROUP
lda colortbl,X ; get color from table
sta HGR_COLOR
; HPLOT X,Y: X= (y,x), Y=a
ldx X_OLDER
lda Y_OLDER
ldy #0
jsr hplot0 ; hplot(x_old,y_old);
; HPLOT to X,Y X=(x,a), y=Y
lda X_OLD
ldx #0
ldy Y_OLD
jsr hglin ; hplot_to(x_old,y_old);
done_with_loop:
lda CURRENT_STEP
cmp MAX_STEPS
bne not_done_with_launch
lda #2
sta STATE
not_done_with_launch:
lda #$c0
jsr WAIT
inc CURRENT_STEP
rts
;==================================
; Start explosion near x_old, y_old
;==================================
start_explosion:
jsr random16
lda SEEDL
and #$f
sec
sbc #8
adc X_OLD
sta XPOS_L ; xpos=x_old+(random()%16)-8; x +/- 8
; FIXME: XPOS can overlow
jsr random16
lda SEEDL
and #$f
sec
sbc #8
adc Y_OLD
sta YPOS_H ; ypos_h=y_old+(random()%16)-8; // y +/- 8
; draw white (with fringes)
lda COLOR_GROUP
clc
adc #$3
tax
lda colortbl,X ; get color from table
sta HGR_COLOR
; hplot(xpos,ypos_h); // draw at center of explosion
; HPLOT X,Y: X= (y,x), Y=a
ldx XPOS_L
lda YPOS_H
ldy #0
jsr hplot0 ; hplot(x_old,y_old);
; Spread the explosion
ldy #1
sty TEMPY ; save Y
lda #3 ; move to continue explosion
sta STATE
rts
;===============================
; Continue Explosion
;===============================
continue_explosion:
ldy TEMPY
;================================
; Draw spreading dots in white
cpy #9
beq explosion_erase
; hcolor_equals(color_group+3);
lda COLOR_GROUP
clc
adc #$3
tax
lda colortbl,X ; get color from table
sta HGR_COLOR
ldx TEMPY
stx OFFSET
jsr explosion
explosion_erase:
;======================
; erase old
; erase with proper color black (0 or 4)
ldx COLOR_GROUP
lda colortbl,X ; get color from table
sta HGR_COLOR
ldx TEMPY
dex
stx OFFSET
jsr explosion
done_with_explosion:
lda #$c0
jsr WAIT
inc TEMPY
lda TEMPY
cmp #10
beq explosion_done
rts
explosion_done:
;==================================
; randomly draw more explosions
;==================================
jsr random16
lda SEEDL
and #$2
sta STATE
; if 0, then move to state 0 (start over)
; if 2, then move to state 2 (new random explosion)
rts
;===============================
; Draw explosion rays
;===============================
;
explosion:
; HPLOT X,Y: X= (y,x), Y=a
clc
lda XPOS_L
adc OFFSET
tax
ldy #0
clc
lda YPOS_H
adc OFFSET
jsr hplot0 ; hplot(xpos+o,ypos_h+o); SE
clc
lda XPOS_L
adc OFFSET
tax
ldy #0
sec
lda YPOS_H
sbc OFFSET
jsr hplot0 ; hplot(xpos+o,ypos_h-o); NE
sec
lda XPOS_L
sbc OFFSET
tax
ldy #0
sec
lda YPOS_H
sbc OFFSET
jsr hplot0 ; hplot(xpos-o,ypos_h-o); NW
sec
lda XPOS_L
sbc OFFSET
tax
ldy #0
clc
lda YPOS_H
adc OFFSET
jsr hplot0 ; hplot(xpos-o,ypos_h+o); SW
; HPLOT X,Y: X= (y,x), Y=a
ldx XPOS_L
ldy #0
clc
lda OFFSET
adc OFFSET
adc OFFSET
lsr
adc YPOS_H
jsr hplot0 ; hplot(xpos,ypos_h+(o*1.5)); S
ldx XPOS_L
ldy #0
clc ; O O*1.5 NEG
lda OFFSET ; 0 = 0 0
adc OFFSET ; 1 = 1 -1
adc OFFSET ; 2 = 3 -3
lsr ; 3 = 4 -4
eor #$FF ; 4 = 6 -6
clc
adc #1
adc YPOS_H
jsr hplot0 ; hplot(xpos,ypos_h-(o*1.5)); N
; HPLOT X,Y: X= (y,x), Y=a
clc
lda OFFSET
adc OFFSET
adc OFFSET
lsr
adc XPOS_L
tax
ldy #0
lda YPOS_H
jsr hplot0 ; hplot(xpos+(o*1.5),ypos_h); E
clc ; O O*1.5 NEG
lda OFFSET ; 0 = 0 0
adc OFFSET ; 1 = 1 -1
adc OFFSET ; 2 = 3 -3
lsr ; 3 = 4 -4
eor #$FF ; 4 = 6 -6
clc
adc #1
adc XPOS_L
tax
ldy #0
lda YPOS_H
jsr hplot0 ; hplot(xpos-(o*1.5),ypos_h); // W
rts
;=============================
; Draw the stars
;=============================
; 7+ 280X + 5
; 16 stars = 4492
draw_stars:
; HCOLOR = 3, white (though they are drawn purple)
lda #$7f ; 2
sta HGR_COLOR ; 3
ldy #0 ; 2
;===========
; 7
star_loop:
tya ; 2
pha ; 3
; HPLOT X,Y
; X= (y,x), Y=a
ldx stars,Y ; 4+
lda stars+1,Y ; 4+
ldy #0 ; 2
jsr hplot0 ;6+244
pla ; 4
tay ; 2
iny ; 2
iny ; 2
cpy #NUMSTARS*2 ; 2
bne star_loop ; 3
;============
; 279
; -1
rts ; 6
stars: ; even x so they are purple
.byte 28,107, 108, 88, 126, 88, 136, 95
.byte 150,108, 148,120, 172,124, 180,109
.byte 216, 21, 164, 40, 124, 18, 60, 12
.byte 240,124, 94,125, 12, 22, 216,116