Rebuild Fireworks simulator

README.md

@@ -33,7 +33,7 @@ Browse and run the collection at [c64.p20.dev](https://c64.p20.dev).
 | SID Arpeggiator | 2026-10-16 | Music | Machine Code | `A`-`K`, `1`-`3`, `+`, `-`, Space, `Q` | Shape a looping SID arpeggio with notes, waveforms, and tempo controls. | [ASM](sid-arpeggiator/sid-arpeggiator.asm) | [Run](https://c64.p20.dev/program/sid-arpeggiator) |
 | Paddle Ball | 2026-10-16 | Arcade | Machine Code | `A`, `D`, Space, `Q` | Keep a fast-moving ball in play with a screen-edge paddle. | [ASM](paddle-ball/paddle-ball.asm) | [Run](https://c64.p20.dev/program/paddle-ball) |
 | Smooth Scroller | 2026-10-16 | Demo | Machine Code | `+`, `-`, `C`, `Q` | Send a message gliding across the screen with VIC-II fine scrolling. | [ASM](smooth-scroller/smooth-scroller.asm) | [Run](https://c64.p20.dev/program/smooth-scroller) |
-| Fireworks | 2026-10-16 | Demo | Machine Code | Space, `C`, `Q` | Launch colorful PETSCII fireworks into a night sky. | [ASM](fireworks/fireworks.asm) | [Run](https://c64.p20.dev/program/fireworks) |
+| Fireworks | 2026-10-16 | Demo | Machine Code | Space, `A`, `C`, `1`-`3`, `Q` | Launch colorful, noisy PETSCII fireworks above a twinkling city skyline. | [ASM](fireworks/fireworks.asm) | [Run](https://c64.p20.dev/program/fireworks) |
 | Jiffy Clock | 2026-10-16 | Utility | Machine Code | `R`, Space, `Q` | Turn the C64 jiffy timer into a large live digital clock. | [ASM](jiffy-clock/jiffy-clock.asm) | [Run](https://c64.p20.dev/program/jiffy-clock) |
 | Typing Sprint | 2026-10-16 | Word | Machine Code | `A`-`Z`, Space, `Q` | Race the clock while copying a Commodore-themed phrase. | [ASM](typing-sprint/typing-sprint.asm) | [Run](https://c64.p20.dev/program/typing-sprint) |
 | PETSCII Aquarium | 2026-10-16 | Simulation | Machine Code | `F`, `1`-`3`, `Q` | Watch a tiny animated aquarium and feed its roaming fish. | [ASM](petscii-aquarium/petscii-aquarium.asm) | [Run](https://c64.p20.dev/program/petscii-aquarium) |

fireworks/fireworks.asm

@@ -1,4 +1,7 @@
 !cpu 6510
+
+; Fireworks - an animated PETSCII fireworks simulator with SID effects.
+; Self-starting BASIC line: 10 SYS2061
 * = $0801
 !word basic_end
 !word 10
@@ -8,162 +11,546 @@
 basic_end: !word 0
 
 * = $080d
+SCREEN = $0400
+COLOR  = $d800
+GETIN  = $ffe4
+CHROUT = $ffd2
+
 start:
     lda $d020
     sta old_border
     lda $d021
     sta old_background
+    lda $d418
+    sta old_volume
+    ldx #0
+save_sid:
+    lda $d400,x
+    sta old_sid,x
+    inx
+    cpx #7
+    bne save_sid
     lda #0
     sta $d020
     sta $d021
+    jsr show_splash
     lda #147
-    jsr $ffd2
+    jsr CHROUT
-    ldx #0
+    lda #0
-print_title:
+    sta $d020
-    lda title,x
+    sta $d021
-    beq setup
+    sta show_state
-    jsr $ffd2
+    sta palette
-    inx
+    sta auto_show
-    bne print_title
+    sta tick
-setup:
+    sta seed
-    lda #7
+    lda #3
-    sta center_x
+    sta animation_speed
-    lda #5
+    lda #18
-    sta burst_color
+    sta auto_countdown
-main:
+    lda $a2
-    jsr $ffe4
+    sta last_jiffy
+    jsr draw_skyline
+    jsr draw_stars
+
+main_loop:
+    jsr GETIN
+    beq check_clock
     cmp #81
-    bne not_quit
+    bne check_launch
     jmp exit
-not_quit:
+check_launch:
-    cmp #67
-    bne launch_key
-    inc burst_color
-    lda burst_color
-    and #15
-    sta burst_color
-launch_key:
     cmp #32
-    bne main
+    bne check_auto
-    jsr launch
+    jsr launch_rocket
-    jmp main
+    jmp check_clock
-launch:
+check_auto:
-    lda #22
+    cmp #65
+    bne check_color
+    lda auto_show
+    eor #1
+    sta auto_show
+    lda #4
+    sta auto_countdown
+    jmp check_clock
+check_color:
+    cmp #67
+    bne check_speed_one
+    inc palette
+    lda palette
+    and #3
+    sta palette
+    jmp check_clock
+check_speed_one:
+    cmp #49
+    bne check_speed_two
+    lda #6
+    sta animation_speed
+    jmp check_clock
+check_speed_two:
+    cmp #50
+    bne check_speed_three
+    lda #3
+    sta animation_speed
+    jmp check_clock
+check_speed_three:
+    cmp #51
+    bne check_clock
+    lda #1
+    sta animation_speed
+
+check_clock:
+    lda $a2
+    cmp last_jiffy
+    beq main_loop
+    sta last_jiffy
+    inc tick
+    lda tick
+    cmp animation_speed
+    bcc main_loop
+    lda #0
+    sta tick
+    inc seed
+    jsr twinkle_star
+    lda show_state
+    beq idle_frame
+    cmp #1
+    beq update_rocket
+    jmp update_explosion
+
+idle_frame:
+    lda auto_show
+    bne auto_active
+    jmp main_loop
+auto_active:
+    dec auto_countdown
+    beq auto_launch
+    jmp main_loop
+auto_launch:
+    jsr launch_rocket
+    jmp main_loop
+
+launch_rocket:
+    lda show_state
+    bne launch_done
+    lda seed
+    clc
+    adc $d012
+    and #31
+    cmp #24
+    bcc center_ready
+    sbc #24
+center_ready:
+    clc
+    adc #8
+    sta center_x
+    sta rocket_x
+    lda #20
     sta rocket_y
-rise:
+    lda #1
-    ldx center_x
+    sta show_state
-    ldy rocket_y
+    lda #2
-    lda #46
+    sta trail_length
-    jsr plot
+    jsr rocket_sound
-    jsr delay
+launch_done:
-    ldx center_x
+    rts
-    ldy rocket_y
+
+update_rocket:
+    ; Erase the oldest trail cell.
+    lda rocket_x
+    sta plot_x
+    lda rocket_y
+    clc
+    adc #2
+    cmp #20
+    bcs skip_old_trail
+    sta plot_y
     lda #32
-    jsr plot
+    ldy #0
+    jsr plot_character
+skip_old_trail:
+    ; Turn the old rocket position into a fading trail.
+    lda rocket_y
+    sta plot_y
+    lda #46
+    ldy #7
+    jsr plot_character
     dec rocket_y
     lda rocket_y
-    cmp #7
+    cmp #6
-    bne rise
+    bne draw_rocket
-    ldx #0
+    lda rocket_x
-burst_loop:
+    sta plot_x
-    stx particle_index
-    lda burst_dx,x
-    clc
-    adc center_x
-    sta px
-    lda burst_dy,x
-    clc
-    adc rocket_y
-    tay
-    ldx px
-    lda #42
-    jsr plot
-    ldx particle_index
-    inx
-    cpx #12
-    bne burst_loop
-    jsr long_delay
-    ldx #0
-clear_burst:
-    stx particle_index
-    lda burst_dx,x
-    clc
-    adc center_x
-    sta px
-    lda burst_dy,x
-    clc
-    adc rocket_y
-    tay
-    ldx px
     lda #32
-    jsr plot
+    ldy #0
-    ldx particle_index
+    jsr plot_character
+    lda #2
+    sta show_state
+    lda #0
+    sta explosion_stage
+    jsr explosion_sound
+    jsr draw_explosion
+    rts
+draw_rocket:
+    sta plot_y
+    lda rocket_x
+    sta plot_x
+    lda #94
+    ldy #1
+    jsr plot_character
+    jsr rocket_sound
+    rts
+
+update_explosion:
+    jsr erase_explosion
+    inc explosion_stage
+    lda explosion_stage
+    cmp #5
+    bcs finish_explosion
+    jsr explosion_sound
+    jsr draw_explosion
+    rts
+finish_explosion:
+    lda #0
+    sta show_state
+    lda seed
+    and #15
+    clc
+    adc #8
+    sta auto_countdown
+    jsr silence_sid
+    jsr draw_skyline
+    jsr draw_stars
+    rts
+
+draw_explosion:
+    lda #0
+    sta particle
+draw_particle_loop:
+    jsr select_particle_position
+    lda explosion_stage
+    tax
+    lda burst_chars,x
+    ldx particle
+    ldy particle_colors,x
+    ldx palette
+    beq color_ready
+palette_shift_loop:
+    tya
+    clc
+    adc #3
+    and #15
+    tay
+    dex
+    bne palette_shift_loop
+color_ready:
+    jsr plot_character
+    inc particle
+    lda particle
+    cmp #16
+    bne draw_particle_loop
+    rts
+
+erase_explosion:
+    lda #0
+    sta particle
+erase_particle_loop:
+    jsr select_particle_position
+    lda #32
+    ldy #0
+    jsr plot_character
+    inc particle
+    lda particle
+    cmp #16
+    bne erase_particle_loop
+    rts
+
+select_particle_position:
+    lda explosion_stage
+    asl
+    asl
+    asl
+    asl
+    clc
+    adc particle
+    tax
+    lda burst_dx,x
+    clc
+    adc center_x
+    sta plot_x
+    lda burst_dy,x
+    clc
+    adc #6
+    sta plot_y
+    rts
+
+draw_stars:
+    ldx #0
+star_loop:
+    stx object_index
+    lda star_x,x
+    sta plot_x
+    lda star_y,x
+    sta plot_y
+    txa
+    and #1
+    beq star_dot
+    lda #42
+    bne paint_star
+star_dot:
+    lda #46
+paint_star:
+    ldy #15
+    jsr plot_character
+    ldx object_index
+    inx
+    cpx #18
+    bne star_loop
+    rts
+
+twinkle_star:
+    lda seed
+    and #15
+    tax
+    stx object_index
+    lda star_x,x
+    sta plot_x
+    lda star_y,x
+    sta plot_y
+    lda seed
+    and #1
+    beq twinkle_dot
+    lda #42
+    bne twinkle_paint
+twinkle_dot:
+    lda #46
+twinkle_paint:
+    ldy #1
+    jsr plot_character
+    rts
+
+draw_skyline:
+    ldx #0
+building_loop:
+    stx plot_x
+    lda building_height,x
+    sta height_left
+    lda #24
+    sta plot_y
+building_column:
+    lda #160
+    ldy #11
+    jsr plot_character
+    dec plot_y
+    dec height_left
+    bne building_column
+    inx
+    cpx #40
+    bne building_loop
+    ; Warm windows across the skyline.
+    ldx #0
+window_loop:
+    stx object_index
+    lda window_x,x
+    sta plot_x
+    lda window_y,x
+    sta plot_y
+    lda #81
+    ldy #7
+    jsr plot_character
+    ldx object_index
     inx
     cpx #12
-    bne clear_burst
+    bne window_loop
-    lda center_x
-    clc
-    adc #11
-    cmp #35
-    bcc save_center
-    sbc #31
-save_center:
-    sta center_x
     rts
-plot:
+
-    sta char_value
+rocket_sound:
-    lda row_lo,y
+    lda rocket_y
+    eor #$ff
+    sta $d400
+    lda #22
+    sta $d401
+    lda #$11
+    sta $d404
+    lda #$0f
+    sta $d418
+    rts
+
+explosion_sound:
+    lda #0
+    sta $d400
+    lda #45
+    sta $d401
+    lda #$81
+    sta $d404
+    lda #$08
+    sta $d405
+    lda #$88
+    sta $d406
+    lda #$0f
+    sta $d418
+    rts
+
+silence_sid:
+    lda #0
+    sta $d404
+    sta $d418
+    rts
+
+plot_character:
+    sta character
+    sty character_color
+    ldy plot_y
+    lda screen_row_lo,y
     sta $fb
-    lda row_hi,y
+    lda screen_row_hi,y
     sta $fc
-    txa
+    lda color_row_lo,y
-    tay
-    lda char_value
-    sta ($fb),y
-    lda $fb
-    clc
-    adc #<$d400
     sta $fd
-    lda $fc
+    lda color_row_hi,y
-    adc #>$d400
     sta $fe
-    lda burst_color
+    ldy plot_x
+    lda character
+    sta ($fb),y
+    lda character_color
     sta ($fd),y
     rts
-delay:
+
-    ldx #8
+show_splash:
-delay_outer:
+    lda #<splash_text
+    sta $fb
+    lda #>splash_text
+    sta $fc
     ldy #0
-delay_inner:
+print_splash:
-    dey
+    lda ($fb),y
-    bne delay_inner
+    beq wait_for_space
-    dex
+    jsr CHROUT
-    bne delay_outer
+    inc $fb
+    bne print_splash
+    inc $fc
+    jmp print_splash
+wait_for_space:
+    jsr GETIN
+    cmp #32
+    bne wait_for_space
     rts
-long_delay:
+
-    ldx #45
-    bne delay_outer
 exit:
+    jsr silence_sid
+    ldx #0
+restore_sid:
+    lda old_sid,x
+    sta $d400,x
+    inx
+    cpx #7
+    bne restore_sid
+    lda old_volume
+    sta $d418
     lda old_border
     sta $d020
     lda old_background
     sta $d021
     lda #147
-    jsr $ffd2
+    jsr CHROUT
     rts
 
-title: !byte 147
+splash_text:
-!text "FIREWORKS  SPACE LAUNCH  C COLOR  Q QUIT"
+!byte 147,13,13,13
-!byte 13,0
+!byte 154
-burst_dx: !byte 0,1,2,$ff,$fe,0,0,1,2,$ff,$fe,0
+!text "              FIREWORKS"
-burst_dy: !byte $fe,$ff,0,$ff,0,2,1,1,2,1,2,$ff
+!byte 13,13
-row_lo: !for i,0,24 { !byte <($0400+i*40) }
+!byte 5
-row_hi: !for i,0,24 { !byte >($0400+i*40) }
+!text " A PETSCII SKY FULL OF COLOR AND SOUND"
+!byte 13,13,13
+!byte 153
+!text "                CONTROLS"
+!byte 13,13
+!text "    "
+!byte 158
+!text "SPACE"
+!byte 5
+!text " LAUNCH  "
+!byte 158
+!text "A"
+!byte 5
+!text " AUTO  "
+!byte 158
+!text "C"
+!byte 5
+!text " COLOR"
+!byte 13
+!text "        "
+!byte 158
+!text "1-3"
+!byte 5
+!text " SPEED  "
+!byte 158
+!text "Q"
+!byte 5
+!text " QUIT"
+!byte 13,13,13
+!byte 5
+!text "          HTTPS://C64.P20.DEV"
+!byte 13,13
+!byte 152
+!text "        RELEASED 16 OCTOBER 2026"
+!byte 13,13,13
+!byte 158
+!text "         PRESS SPACE TO START"
+!byte 0
+
+; Five expansion stages, sixteen points per stage. Signed offsets are stored
+; as bytes; normal 6502 wrapping performs the addition around the burst center.
+burst_dx:
+!byte 0,1,1,1,0,$ff,$ff,$ff,0,1,0,$ff,1,1,$ff,$ff
+!byte 0,1,2,1,0,$ff,$fe,$ff,2,2,0,$fe,1,1,$ff,$ff
+!byte 0,2,3,2,0,$fe,$fd,$fe,3,3,0,$fd,1,1,$ff,$ff
+!byte 0,2,4,2,0,$fe,$fc,$fe,4,3,0,$fc,1,1,$ff,$ff
+!byte 0,3,5,3,0,$fd,$fb,$fd,5,4,0,$fb,2,2,$fe,$fe
+burst_dy:
+!byte $ff,$ff,0,1,1,1,0,$ff,$ff,0,1,0,$ff,1,1,$ff
+!byte $fe,$ff,0,1,2,1,0,$ff,$fe,0,2,0,$ff,1,1,$ff
+!byte $fd,$fe,0,2,3,2,0,$fe,$fd,0,3,0,$ff,1,1,$ff
+!byte $fc,$fe,0,2,4,2,0,$fe,$fc,0,4,0,$ff,1,1,$ff
+!byte $fb,$fd,0,3,5,3,0,$fd,$fb,0,5,0,$fe,2,2,$fe
+
+burst_chars: !byte 81,42,43,46,46
+particle_colors: !byte 1,7,10,8,2,5,3,13,1,7,10,8,2,5,3,13
+star_x: !byte 2,5,8,11,14,17,20,23,26,29,32,35,38,4,10,27,34,16
+star_y: !byte 3,8,5,12,4,9,3,13,6,10,4,8,12,15,17,16,14,6
+building_height:
+!byte 3,3,4,4,4,6,6,6,5,5,3,3,7,7,7,7,4,4,5,5
+!byte 5,8,8,8,6,6,4,4,4,7,7,7,5,5,6,6,6,3,3,3
+window_x: !byte 2,6,9,13,16,19,22,25,29,32,35,38
+window_y: !byte 23,21,22,20,23,22,19,21,20,22,21,23
+
+screen_row_lo: !for i,0,24 { !byte <(SCREEN+i*40) }
+screen_row_hi: !for i,0,24 { !byte >(SCREEN+i*40) }
+color_row_lo:  !for i,0,24 { !byte <(COLOR+i*40) }
+color_row_hi:  !for i,0,24 { !byte >(COLOR+i*40) }
+
+show_state: !byte 0
+palette: !byte 0
+auto_show: !byte 0
+auto_countdown: !byte 0
+animation_speed: !byte 0
+tick: !byte 0
+last_jiffy: !byte 0
+seed: !byte 0
 center_x: !byte 0
+rocket_x: !byte 0
 rocket_y: !byte 0
-burst_color: !byte 0
+trail_length: !byte 0
-particle_index: !byte 0
+explosion_stage: !byte 0
-px: !byte 0
+particle: !byte 0
-char_value: !byte 0
+plot_x: !byte 0
+plot_y: !byte 0
+character: !byte 0
+character_color: !byte 0
+height_left: !byte 0
+object_index: !byte 0
 old_border: !byte 0
 old_background: !byte 0
+old_volume: !byte 0
+old_sid: !fill 7,0

programs.json

@@ -151,8 +151,8 @@
   },
   {
     "title": "Fireworks", "category": "Demo", "language": "machine-code", "releaseDate": "2026-10-16",
-    "description": "Launch colorful PETSCII fireworks into a night sky.",
+    "description": "Launch colorful, noisy PETSCII fireworks above a twinkling city skyline.",
-    "controls": [{"keys":["SPACE"],"description":"Launch a firework"},{"keys":["C"],"description":"Choose the next burst color"},{"keys":["Q"],"description":"Return to BASIC"}],
+    "controls": [{"keys":["SPACE"],"description":"Launch a firework"},{"keys":["A"],"description":"Toggle the automatic fireworks show"},{"keys":["C"],"description":"Change color palette"},{"keys":["1","2","3"],"description":"Select animation speed"},{"keys":["Q"],"description":"Return to BASIC"}],
     "path": "fireworks/fireworks.prg", "source": "fireworks/fireworks.asm"
   },
   {