Game 1 Unit 24 of 64 1 hr learning time
Song 4 - Syncopation
Adding a fourth song that emphasises off-beats. Notes land between expected beats, challenging players' rhythm intuition.
38% of SID Symphony
Syncopation is the rhythmic surprise. Instead of landing on expected beats, notes arrive between them—pushing the feel forward, creating tension.
This unit adds “Off-Beat”—a fourth song at 125 BPM where notes deliberately avoid strong beats. Players must fight their natural instinct to hit on the downbeat.
Run It
Assemble and run:
acme -f cbm -o symphony.prg symphony.asm
The menu now shows four songs. Select “Off-Beat” and feel the difference—notes arrive when you don’t expect them.
What Is Syncopation?
In music, syncopation means emphasising weak beats or off-beats:
| Beat Position | Type | Feel |
|---|---|---|
| 0, 4, 8, 12… | Strong beat | Expected, stable |
| 2, 6, 10, 14… | Weak beat | Slightly off |
| 1, 3, 5, 7… | Off-beat | Surprising, pushed |
Our first three songs placed notes primarily on strong beats. Song 4 inverts this—notes land on off-beats, creating a “pushed” feeling.
Syncopated Patterns
Compare a normal pattern to a syncopated one:
Normal: [0]--[4]--[8]--[12]--[16] (on the beat)
Synco: -[1]--[5]--[9]--[13]--[17] (off the beat)The syncopated version feels like it’s rushing ahead. Players must resist the urge to hit early.
Song 4 Data Structure
Like our other songs, Song 4 has three difficulty variants:
; --- EASY: Sparse syncopated notes (10 notes) ---
song4_easy:
!byte 1, 1, $47 ; Off-beat accent
!byte 9, 2, $3B ; Pushed note
!byte 17, 3, $27 ; Syncopated hit
; ... 10 notes on prominent off-beats
; --- NORMAL: Syncopated with anchors (32 notes) ---
song4_normal:
!byte 0, 1, $47 ; Anchor
!byte 1, 2, $3B ; Off-beat
!byte 3, 3, $27 ; Syncopated
!byte 4, 1, $47 ; Anchor
; ... mix of anchors and off-beats
; --- HARD: Dense syncopated chaos (56 notes) ---
song4_hard:
!byte 0, 1, $47 ; Anchor
!byte 1, 2, $3B ; Off-beat
!byte 1, 3, $27 ; Chord
!byte 3, 1, $47 ; Syncopated
; ... nearly every off-beat filledThe Anchor Concept
Pure syncopation is disorienting. Normal and Hard modes include “anchors”—notes on strong beats that help players stay oriented:
!byte 0, 1, $47 ; Anchor - strong beat
!byte 1, 2, $3B ; Off-beat - syncopated
!byte 3, 3, $27 ; Syncopated
!byte 4, 1, $47 ; Anchor - strong beatAnchors on beats 0, 4, 8, etc. provide reference points. The off-beat notes between them create the syncopated feel without losing the listener entirely.
Tempo Choice: 125 BPM
We chose 125 BPM deliberately:
| Song | BPM | Character |
|---|---|---|
| First Steps | 120 | Relaxed |
| Upbeat Groove | 130 | Energetic |
| Speed Rush | 150 | Frantic |
| Off-Beat | 125 | Groovy |
125 BPM sits between our relaxed and energetic songs. Fast enough to feel lively, slow enough that players can process the unexpected note positions.
Frames Per Beat
At 125 BPM:
frames_per_beat = 3000 / 125 = 24 framesThis gives players 480ms per beat (24 frames ÷ 50 fps)—enough time to adjust when notes don’t land where expected.
Menu Update
The menu now handles four songs:
draw_cursor:
; Clear all cursor positions
lda #CHAR_SPACE
sta SCREEN + (8 * 40) + 12
sta SCREEN + (10 * 40) + 12
sta SCREEN + (12 * 40) + 12
sta SCREEN + (14 * 40) + 12
; Draw cursor at current position
lda cursor_pos
beq cursor_song1
cmp #1
beq cursor_song2
cmp #2
beq cursor_song3
jmp cursor_song4Songs display on rows 8, 10, 12, and 14—evenly spaced down the menu.
Song Selection Logic
The transition routine handles all four songs:
transition_to_game:
lda selected_song
beq setup_song1
cmp #1
beq setup_song2
cmp #2
beq setup_song3
jmp setup_song4
setup_song4:
lda #TEMPO_SONG4
sta frames_per_beat
lda #LENGTH_SONG4
sta song_length
; Select difficulty variant
lda difficulty
cmp #DIFF_EASY
beq load_s4_easy
cmp #DIFF_NORMAL
beq load_s4_normal
jmp load_s4_hardWhy Syncopation Challenges Players
Most rhythm games train players to expect notes on the beat. Syncopation breaks this expectation:
- Visual prediction fails - Eyes see note approaching, brain predicts strong beat
- Motor preparation misfires - Finger starts moving for expected timing
- Correction required - Must hold slightly, hit on off-beat
This creates a distinctive “groove” feeling when mastered—the push-pull between expectation and reality.
Difficulty Progression with Syncopation
| Difficulty | Notes | Strategy |
|---|---|---|
| Easy | 10 | Learn where off-beats feel |
| Normal | 32 | Mix of anchors and off-beats |
| Hard | 56 | Dense syncopation with chords |
Easy mode strips to the most prominent syncopated accents. Normal adds anchors for orientation. Hard fills nearly every off-beat, requiring players to fully internalise the pushed feel.
The Complete Code
; ============================================================================
; SID SYMPHONY - Unit 24: Song 4 - Syncopation
; ============================================================================
; Adding a fourth song that emphasises off-beats. Notes land between expected
; beats, challenging players' rhythm intuition. A visual beat marker pulses
; on downbeats to help players stay oriented.
;
; New concepts: Syncopation, off-beat patterns, visual beat indicator
;
; Controls: Z = Track 1, X = Track 2, C = Track 3
; Up/Down = Song selection, Left/Right = Difficulty
; P = Toggle practice mode, +/- = Speed adjustment
; Fire/Space = Start game
; ============================================================================
; ============================================================================
; CUSTOMISATION SECTION
; ============================================================================
; Screenshot mode - set to 1 to skip title and show menu immediately
; Used for automated screenshot capture. Override with: acme -DSCREENSHOT_MODE=1
!ifndef SCREENSHOT_MODE { SCREENSHOT_MODE = 0 }
; SID Voice Settings (for note playback)
VOICE1_WAVE = $21 ; Sawtooth for track 1
VOICE2_WAVE = $41 ; Pulse for track 2
VOICE3_WAVE = $11 ; Triangle for track 3
VOICE1_FREQ = $1C
VOICE2_FREQ = $0E
VOICE3_FREQ = $07
VOICE_AD = $09 ; Attack=0, Decay=9
VOICE_SR = $00 ; Sustain=0, Release=0
PULSE_WIDTH = $08
; Perfect hit sound - bright and satisfying
PERFECT_SFX_FREQ = $30 ; Higher pitch
PERFECT_SFX_WAVE = $21 ; Sawtooth (bright)
PERFECT_SFX_AD = $08 ; Fast attack, medium decay
PERFECT_SFX_SR = $00 ; No sustain
; Good hit sound - positive but lesser
GOOD_SFX_FREQ = $20 ; Lower pitch than perfect
GOOD_SFX_WAVE = $11 ; Triangle (softer)
GOOD_SFX_AD = $0A ; Slightly slower decay
GOOD_SFX_SR = $00 ; No sustain
; Miss sound settings - harsh buzz
MISS_FREQ = $08
MISS_WAVE = $81 ; Noise
MISS_AD = $00 ; Instant attack
MISS_SR = $A0 ; Quick sustain, fast release
; Menu sound settings
MENU_SELECT_FREQ = $18 ; Menu click pitch
MENU_SELECT_WAVE = $41 ; Pulse for click
MENU_SELECT_AD = $00 ; Instant
MENU_SELECT_SR = $80 ; Very short
MENU_MOVE_FREQ = $10 ; Lower pitch for cursor move
MENU_MOVE_WAVE = $11 ; Triangle (soft)
MENU_MOVE_AD = $00 ; Instant
MENU_MOVE_SR = $40 ; Very short
; Visual Settings
BORDER_COL = 0
BG_COL = 0
TRACK1_NOTE_COL = 10 ; Light red for high track
TRACK2_NOTE_COL = 13 ; Light green for mid track
TRACK3_NOTE_COL = 14 ; Light blue for low track
TRACK_LINE_COL = 11 ; Grey for track lines
HIT_ZONE_COL = 7 ; Yellow for hit zone
HIT_COL = 1
PERFECT_COL = 1 ; White flash for perfect
GOOD_COL = 7 ; Yellow flash for good
MISS_COL = 2 ; Red flash for miss
HEALTH_COL = 5 ; Green for health bar
PROGRESS_COL = 3 ; Cyan for progress bar
COMBO_COL = 13 ; Light green for combo
; Title screen colours
TITLE_COL = 1 ; White for title
SUBTITLE_COL = 11 ; Grey for subtitle
MENU_COL = 7 ; Yellow for menu items
CURSOR_COL = 1 ; White for cursor
EASY_COL = 5 ; Green for Easy
NORMAL_COL = 7 ; Yellow for Normal
HARD_COL = 2 ; Red for Hard
; ============================================================================
; SCORING SETTINGS (BALANCED)
; ============================================================================
PERFECT_SCORE = 100 ; Perfect hit value
GOOD_SCORE = 50 ; Good hit value
; ============================================================================
; COMBO SETTINGS (BALANCED)
; ============================================================================
COMBO_TIER_2 = 10 ; 2x multiplier at 10 hits
COMBO_TIER_3 = 25 ; 3x multiplier at 25 hits
COMBO_TIER_4 = 50 ; 4x multiplier at 50 hits
; Combo border colours (escalating intensity)
COMBO_BORDER_0 = 0 ; Black - no combo
COMBO_BORDER_1 = 11 ; Dark grey - building
COMBO_BORDER_2 = 5 ; Green - 2x (tier 2)
COMBO_BORDER_3 = 7 ; Yellow - 3x (tier 3)
COMBO_BORDER_4 = 2 ; Red - 4x (tier 4 / fire!)
; ============================================================================
; HEALTH SETTINGS (BASE VALUES - MODIFIED BY DIFFICULTY)
; ============================================================================
HEALTH_MAX = 64 ; Maximum health
HEALTH_START = 32 ; Start at half health
HEALTH_PERFECT = 4 ; Gain 4 for perfect
HEALTH_GOOD = 2 ; Gain 2 for good
; Health loss per difficulty
HEALTH_MISS_EASY = 4 ; Forgiving
HEALTH_MISS_NORMAL = 8 ; Balanced
HEALTH_MISS_HARD = 12 ; Punishing
; ============================================================================
; HIT DETECTION SETTINGS (BASE - MODIFIED BY DIFFICULTY)
; ============================================================================
; Hit zone column range (where notes can be hit)
HIT_ZONE_START = 2 ; Leftmost hittable column
HIT_ZONE_END = 6 ; Rightmost hittable column
; Perfect timing column (centre of hit zone)
PERFECT_COL_POS = 4
; Timing windows per difficulty (columns from perfect)
; Easy: Perfect ±2, Good ±4
; Normal: Perfect ±1, Good ±2
; Hard: Perfect ±0, Good ±1
PERFECT_WINDOW_EASY = 2
PERFECT_WINDOW_NORMAL = 1
PERFECT_WINDOW_HARD = 0
GOOD_WINDOW_EASY = 4
GOOD_WINDOW_NORMAL = 2
GOOD_WINDOW_HARD = 1
; ============================================================================
; DIFFICULTY SETTINGS
; ============================================================================
DIFF_EASY = 0
DIFF_NORMAL = 1
DIFF_HARD = 2
; ============================================================================
; SONG SETTINGS
; ============================================================================
PROGRESS_WIDTH = 16 ; Progress bar width
; Per-song tempo (frames per beat)
TEMPO_SONG1 = 25 ; 120 BPM
TEMPO_SONG2 = 23 ; 130 BPM
TEMPO_SONG3 = 20 ; 150 BPM
TEMPO_SONG4 = 24 ; 125 BPM (syncopated feel)
; Per-song length (beats)
LENGTH_SONG1 = 64
LENGTH_SONG2 = 64
LENGTH_SONG3 = 64
LENGTH_SONG4 = 64
; ============================================================================
; MENU SETTINGS
; ============================================================================
NUM_SONGS = 4
KEY_DELAY = 10 ; Frames between key repeats
; ============================================================================
; PRACTICE MODE SETTINGS
; ============================================================================
; Speed multipliers (stored as frame adjustment)
; Higher value = slower (more frames per beat)
SPEED_HALF = 2 ; 0.5x speed (double frames)
SPEED_3QRTR = 1 ; 0.75x speed (4/3 frames, approx +1)
SPEED_NORMAL = 0 ; 1.0x speed (no adjustment)
NUM_SPEEDS = 3
PRACTICE_COL = 3 ; Cyan for practice mode indicator
; ============================================================================
; GAME STATES
; ============================================================================
STATE_TITLE = 0 ; Title screen
STATE_MENU = 1 ; Song selection menu
STATE_PLAYING = 2 ; Gameplay
STATE_RESULTS = 3 ; Success results
STATE_GAMEOVER = 4 ; Failure game over
; ============================================================================
; MEMORY MAP
; ============================================================================
SCREEN = $0400
COLRAM = $D800
BORDER = $D020
BGCOL = $D021
CHARPTR = $D018
CHARSET = $3000
; SID registers
SID = $D400
SID_V1_FREQ_LO = $D400
SID_V1_FREQ_HI = $D401
SID_V1_PWHI = $D403
SID_V1_CTRL = $D404
SID_V1_AD = $D405
SID_V1_SR = $D406
SID_V2_FREQ_LO = $D407
SID_V2_FREQ_HI = $D408
SID_V2_PWHI = $D40A
SID_V2_CTRL = $D40B
SID_V2_AD = $D40C
SID_V2_SR = $D40D
SID_V3_FREQ_LO = $D40E
SID_V3_FREQ_HI = $D40F
SID_V3_PWHI = $D411
SID_V3_CTRL = $D412
SID_V3_AD = $D413
SID_V3_SR = $D414
SID_VOLUME = $D418
; CIA keyboard and joystick
CIA1_PRA = $DC00
CIA1_PRB = $DC01
; Track positions (balanced spacing)
TRACK1_ROW = 8 ; High track
TRACK2_ROW = 12 ; Mid track
TRACK3_ROW = 16 ; Low track
; HUD positions
HEALTH_ROW = 23 ; Health bar row
PROGRESS_ROW = 24 ; Progress bar row
; Combo display position
COMBO_ROW = 2 ; Combo display row
; Hit zone
HIT_ZONE_COLUMN = 3 ; Where notes are hit (visual)
; Custom character codes
CHAR_NOTE = 128
CHAR_TRACK = 129
CHAR_HITZONE = 130
CHAR_SPACE = 32
CHAR_BAR_FULL = 131
CHAR_BAR_EMPTY = 132
CHAR_CURSOR = 62 ; > character for menu cursor
CHAR_ARROW_L = 60 ; < for difficulty
CHAR_ARROW_R = 62 ; > for difficulty
; Note settings
MAX_NOTES = 8 ; Maximum simultaneous notes
NOTE_SPAWN_COL = 37 ; Where notes appear
; Timing
END_DELAY_FRAMES = 75 ; 1.5 seconds after song ends
; Zero page
ZP_PTR = $FB
ZP_PTR_HI = $FC
; Variables
frame_count = $02
beat_count = $03
song_pos = $04
song_pos_hi = $05
temp_track = $06
key_pressed = $07
hit_quality = $08
border_flash = $09
miss_track = $0A
game_state = $0B
hit_note_freq = $0C
song_beat = $0D
song_ended = $0E
end_delay = $0F
cursor_pos = $10 ; Menu cursor position
key_delay_count = $11 ; Key repeat delay counter
selected_song = $12 ; Which song to play
frames_per_beat = $13 ; Current song's tempo
song_length = $14 ; Current song's length
difficulty = $15 ; 0=Easy, 1=Normal, 2=Hard
perfect_window = $16 ; Current perfect timing window
good_window = $17 ; Current good timing window
health_miss_amt = $18 ; Health loss on miss
practice_mode = $19 ; 0=Normal play, 1=Practice mode (NEW!)
speed_setting = $1A ; 0=0.5x, 1=0.75x, 2=1.0x (NEW!)
; ----------------------------------------------------------------------------
; BASIC Stub
; ----------------------------------------------------------------------------
* = $0801
!byte $0C, $08
!byte $0A, $00
!byte $9E
!text "2064"
!byte $00
!byte $00, $00
; ----------------------------------------------------------------------------
; Main Program
; ----------------------------------------------------------------------------
* = $0810
start:
jsr copy_charset
jsr init_sid
; Start with Normal difficulty
lda #DIFF_NORMAL
sta difficulty
; Practice mode off, normal speed
lda #0
sta practice_mode
lda #NUM_SPEEDS-1 ; Start at 1.0x (normal speed)
sta speed_setting
!if SCREENSHOT_MODE = 1 {
; Screenshot mode: skip title, go to menu
jsr show_menu
lda #STATE_MENU
sta game_state
} else {
; Normal mode: show title screen
jsr show_title
lda #STATE_TITLE
sta game_state
}
main_loop:
lda #$FF
wait_raster:
cmp $D012
bne wait_raster
lda game_state
cmp #STATE_TITLE
beq do_title
cmp #STATE_MENU
beq do_menu
cmp #STATE_PLAYING
beq do_playing
cmp #STATE_RESULTS
beq do_results
jmp do_gameover
do_title:
jsr update_title
jmp main_loop
do_menu:
jsr update_menu
jmp main_loop
do_playing:
jsr update_playing
jmp main_loop
do_results:
jsr update_results
jmp main_loop
do_gameover:
jsr update_gameover
jmp main_loop
; ----------------------------------------------------------------------------
; Show Title Screen
; ----------------------------------------------------------------------------
show_title:
; Clear screen
lda #BORDER_COL
sta BORDER
lda #BG_COL
sta BGCOL
ldx #0
lda #CHAR_SPACE
clear_title:
sta SCREEN,x
sta SCREEN+$100,x
sta SCREEN+$200,x
sta SCREEN+$2E8,x
inx
bne clear_title
; Draw big title "SID SYMPHONY"
ldx #0
draw_title_text:
lda title_big,x
beq draw_title_done
sta SCREEN + (8 * 40) + 14,x
lda #TITLE_COL
sta COLRAM + (8 * 40) + 14,x
inx
jmp draw_title_text
draw_title_done:
; Draw subtitle "A RHYTHM GAME"
ldx #0
draw_subtitle:
lda subtitle_text,x
beq draw_subtitle_done
sta SCREEN + (10 * 40) + 13,x
lda #SUBTITLE_COL
sta COLRAM + (10 * 40) + 13,x
inx
jmp draw_subtitle
draw_subtitle_done:
; Draw controls
ldx #0
draw_controls:
lda controls_text,x
beq draw_controls_done
sta SCREEN + (14 * 40) + 11,x
lda #11
sta COLRAM + (14 * 40) + 11,x
inx
jmp draw_controls
draw_controls_done:
; Draw track info
ldx #0
draw_track_info:
lda track_info,x
beq draw_track_done
sta SCREEN + (16 * 40) + 9,x
lda #11
sta COLRAM + (16 * 40) + 9,x
inx
jmp draw_track_info
draw_track_done:
; Draw "PRESS FIRE TO START"
ldx #0
draw_press_fire:
lda press_fire_text,x
beq draw_press_done
sta SCREEN + (20 * 40) + 10,x
lda #7 ; Yellow
sta COLRAM + (20 * 40) + 10,x
inx
jmp draw_press_fire
draw_press_done:
rts
title_big:
!scr "sid symphony"
!byte 0
subtitle_text:
!scr "a rhythm game"
!byte 0
controls_text:
!scr "controls: z / x / c"
!byte 0
track_info:
!scr "hit notes as they reach"
!byte 0
press_fire_text:
!scr "press fire to start"
!byte 0
; ----------------------------------------------------------------------------
; Update Title State
; ----------------------------------------------------------------------------
update_title:
; Check for fire button (joystick port 2)
lda CIA1_PRA
and #$10 ; Bit 4 = fire
beq title_fire_pressed
; Also check space bar as alternative
lda #$7F
sta CIA1_PRA
lda CIA1_PRB
and #$10 ; Space
beq title_fire_pressed
; No input - stay on title
lda #$FF
sta CIA1_PRA
rts
title_fire_pressed:
lda #$FF
sta CIA1_PRA
; Play menu select sound
jsr play_menu_select
; Go to song selection menu
jsr show_menu
lda #STATE_MENU
sta game_state
rts
; ----------------------------------------------------------------------------
; Show Song Selection Menu
; ----------------------------------------------------------------------------
show_menu:
; Clear screen
ldx #0
lda #CHAR_SPACE
clear_menu:
sta SCREEN,x
sta SCREEN+$100,x
sta SCREEN+$200,x
sta SCREEN+$2E8,x
inx
bne clear_menu
; Initialise cursor
lda #0
sta cursor_pos
sta key_delay_count
; Draw menu title
ldx #0
draw_menu_title:
lda menu_title,x
beq draw_menu_title_done
sta SCREEN + (3 * 40) + 12,x
lda #TITLE_COL
sta COLRAM + (3 * 40) + 12,x
inx
jmp draw_menu_title
draw_menu_title_done:
; Draw song list
jsr draw_song_list
; Draw difficulty section
jsr draw_difficulty
; Draw practice mode section
jsr draw_practice_mode
; Draw instructions
ldx #0
draw_menu_instr:
lda menu_instructions,x
beq draw_menu_instr_done
sta SCREEN + (21 * 40) + 1,x
lda #SUBTITLE_COL
sta COLRAM + (21 * 40) + 1,x
inx
jmp draw_menu_instr
draw_menu_instr_done:
; Draw practice instructions
ldx #0
draw_prac_instr:
lda practice_instructions,x
beq draw_prac_instr_done
sta SCREEN + (22 * 40) + 5,x
lda #SUBTITLE_COL
sta COLRAM + (22 * 40) + 5,x
inx
jmp draw_prac_instr
draw_prac_instr_done:
rts
menu_title:
!scr "select a song"
!byte 0
menu_instructions:
!scr "up/down:song left/right:difficulty"
!byte 0
practice_instructions:
!scr "p:practice +/-:speed"
!byte 0
; ----------------------------------------------------------------------------
; Draw Song List
; ----------------------------------------------------------------------------
draw_song_list:
; Song 1: "First Steps" (120 BPM)
ldx #0
draw_song1:
lda song1_name,x
beq draw_song1_done
sta SCREEN + (8 * 40) + 14,x
lda #MENU_COL
sta COLRAM + (8 * 40) + 14,x
inx
jmp draw_song1
draw_song1_done:
; Song 1 tempo info
ldx #0
draw_tempo1:
lda song1_tempo_text,x
beq draw_tempo1_done
sta SCREEN + (8 * 40) + 27,x
lda #SUBTITLE_COL
sta COLRAM + (8 * 40) + 27,x
inx
jmp draw_tempo1
draw_tempo1_done:
; Song 2: "Upbeat Groove" (130 BPM)
ldx #0
draw_song2:
lda song2_name,x
beq draw_song2_done
sta SCREEN + (10 * 40) + 14,x
lda #MENU_COL
sta COLRAM + (10 * 40) + 14,x
inx
jmp draw_song2
draw_song2_done:
; Song 2 tempo info
ldx #0
draw_tempo2:
lda song2_tempo_text,x
beq draw_tempo2_done
sta SCREEN + (10 * 40) + 27,x
lda #SUBTITLE_COL
sta COLRAM + (10 * 40) + 27,x
inx
jmp draw_tempo2
draw_tempo2_done:
; Song 3: "Speed Rush" (150 BPM)
ldx #0
draw_song3:
lda song3_name,x
beq draw_song3_done
sta SCREEN + (12 * 40) + 14,x
lda #MENU_COL
sta COLRAM + (12 * 40) + 14,x
inx
jmp draw_song3
draw_song3_done:
; Song 3 tempo info
ldx #0
draw_tempo3:
lda song3_tempo_text,x
beq draw_tempo3_done
sta SCREEN + (12 * 40) + 27,x
lda #SUBTITLE_COL
sta COLRAM + (12 * 40) + 27,x
inx
jmp draw_tempo3
draw_tempo3_done:
; Song 4: "Off-Beat" (125 BPM)
ldx #0
draw_song4:
lda song4_name,x
beq draw_song4_done
sta SCREEN + (14 * 40) + 14,x
lda #MENU_COL
sta COLRAM + (14 * 40) + 14,x
inx
jmp draw_song4
draw_song4_done:
; Song 4 tempo info
ldx #0
draw_tempo4:
lda song4_tempo_text,x
beq draw_tempo4_done
sta SCREEN + (14 * 40) + 27,x
lda #SUBTITLE_COL
sta COLRAM + (14 * 40) + 27,x
inx
jmp draw_tempo4
draw_tempo4_done:
; Draw cursor at current position
jsr draw_cursor
rts
; Song names and info
song1_name:
!scr "first steps"
!byte 0
song1_tempo_text:
!scr "(120 bpm)"
!byte 0
song2_name:
!scr "upbeat groove"
!byte 0
song2_tempo_text:
!scr "(130 bpm)"
!byte 0
song3_name:
!scr "speed rush"
!byte 0
song3_tempo_text:
!scr "(150 bpm)"
!byte 0
song4_name:
!scr "off-beat"
!byte 0
song4_tempo_text:
!scr "(125 bpm)"
!byte 0
; ----------------------------------------------------------------------------
; Draw Difficulty Selection
; ----------------------------------------------------------------------------
draw_difficulty:
; Draw "DIFFICULTY:" label
ldx #0
draw_diff_label:
lda diff_label,x
beq draw_diff_label_done
sta SCREEN + (15 * 40) + 10,x
lda #TITLE_COL
sta COLRAM + (15 * 40) + 10,x
inx
jmp draw_diff_label
draw_diff_label_done:
; Draw arrows
lda #CHAR_ARROW_L
sta SCREEN + (15 * 40) + 22
lda #SUBTITLE_COL
sta COLRAM + (15 * 40) + 22
lda #CHAR_ARROW_R
sta SCREEN + (15 * 40) + 30
lda #SUBTITLE_COL
sta COLRAM + (15 * 40) + 30
; Draw current difficulty
jsr draw_current_difficulty
rts
diff_label:
!scr "difficulty:"
!byte 0
; ----------------------------------------------------------------------------
; Draw Current Difficulty Name
; ----------------------------------------------------------------------------
draw_current_difficulty:
; Clear difficulty name area
lda #CHAR_SPACE
sta SCREEN + (15 * 40) + 24
sta SCREEN + (15 * 40) + 25
sta SCREEN + (15 * 40) + 26
sta SCREEN + (15 * 40) + 27
sta SCREEN + (15 * 40) + 28
lda difficulty
cmp #DIFF_EASY
beq draw_diff_easy
cmp #DIFF_NORMAL
beq draw_diff_normal
jmp draw_diff_hard
draw_diff_easy:
ldx #0
draw_easy_text:
lda easy_text,x
beq draw_diff_done
sta SCREEN + (15 * 40) + 24,x
lda #EASY_COL
sta COLRAM + (15 * 40) + 24,x
inx
jmp draw_easy_text
draw_diff_normal:
ldx #0
draw_normal_text:
lda normal_text,x
beq draw_diff_done
sta SCREEN + (15 * 40) + 24,x
lda #NORMAL_COL
sta COLRAM + (15 * 40) + 24,x
inx
jmp draw_normal_text
draw_diff_hard:
ldx #0
draw_hard_text:
lda hard_text,x
beq draw_diff_done
sta SCREEN + (15 * 40) + 24,x
lda #HARD_COL
sta COLRAM + (15 * 40) + 24,x
inx
jmp draw_hard_text
draw_diff_done:
rts
easy_text:
!scr "easy"
!byte 0
normal_text:
!scr "normal"
!byte 0
hard_text:
!scr "hard"
!byte 0
; ----------------------------------------------------------------------------
; Draw Practice Mode Section
; ----------------------------------------------------------------------------
draw_practice_mode:
; Draw "PRACTICE:" label
ldx #0
draw_prac_label:
lda prac_label,x
beq draw_prac_label_done
sta SCREEN + (17 * 40) + 12,x
lda #TITLE_COL
sta COLRAM + (17 * 40) + 12,x
inx
jmp draw_prac_label
draw_prac_label_done:
; Draw current state
jsr draw_practice_state
; Draw speed section
ldx #0
draw_speed_label:
lda speed_label,x
beq draw_speed_label_done
sta SCREEN + (18 * 40) + 14,x
lda #TITLE_COL
sta COLRAM + (18 * 40) + 14,x
inx
jmp draw_speed_label
draw_speed_label_done:
jsr draw_speed_state
rts
prac_label:
!scr "practice:"
!byte 0
speed_label:
!scr "speed:"
!byte 0
; Draw ON/OFF based on practice_mode
draw_practice_state:
lda practice_mode
beq draw_prac_off
; Draw ON
lda #'o'
sta SCREEN + (17 * 40) + 22
lda #'n'
sta SCREEN + (17 * 40) + 23
lda #CHAR_SPACE
sta SCREEN + (17 * 40) + 24
lda #PRACTICE_COL
sta COLRAM + (17 * 40) + 22
sta COLRAM + (17 * 40) + 23
rts
draw_prac_off:
; Draw OFF
lda #'o'
sta SCREEN + (17 * 40) + 22
lda #'f'
sta SCREEN + (17 * 40) + 23
lda #'f'
sta SCREEN + (17 * 40) + 24
lda #SUBTITLE_COL
sta COLRAM + (17 * 40) + 22
sta COLRAM + (17 * 40) + 23
sta COLRAM + (17 * 40) + 24
rts
; Draw speed (0.5x / 0.75x / 1.0x)
draw_speed_state:
; Clear speed area
lda #CHAR_SPACE
sta SCREEN + (18 * 40) + 21
sta SCREEN + (18 * 40) + 22
sta SCREEN + (18 * 40) + 23
sta SCREEN + (18 * 40) + 24
sta SCREEN + (18 * 40) + 25
lda speed_setting
beq draw_speed_half
cmp #1
beq draw_speed_3qrtr
jmp draw_speed_normal
draw_speed_half:
ldx #0
draw_half_text:
lda half_text,x
beq draw_speed_done
sta SCREEN + (18 * 40) + 21,x
lda #EASY_COL ; Green - slowest
sta COLRAM + (18 * 40) + 21,x
inx
jmp draw_half_text
draw_speed_3qrtr:
ldx #0
draw_3qrtr_text:
lda qrtr_text,x
beq draw_speed_done
sta SCREEN + (18 * 40) + 21,x
lda #NORMAL_COL ; Yellow - medium
sta COLRAM + (18 * 40) + 21,x
inx
jmp draw_3qrtr_text
draw_speed_normal:
ldx #0
draw_normal_speed_text:
lda full_text,x
beq draw_speed_done
sta SCREEN + (18 * 40) + 21,x
lda #TITLE_COL ; White - full speed
sta COLRAM + (18 * 40) + 21,x
inx
jmp draw_normal_speed_text
draw_speed_done:
rts
half_text:
!scr "0.5x"
!byte 0
qrtr_text:
!scr "0.75x"
!byte 0
full_text:
!scr "1.0x"
!byte 0
; ----------------------------------------------------------------------------
; Draw Menu Cursor
; ----------------------------------------------------------------------------
draw_cursor:
; Clear all cursor positions
lda #CHAR_SPACE
sta SCREEN + (8 * 40) + 12
sta SCREEN + (10 * 40) + 12
sta SCREEN + (12 * 40) + 12
sta SCREEN + (14 * 40) + 12
; Draw cursor at current position
lda cursor_pos
beq cursor_song1
cmp #1
beq cursor_song2
cmp #2
beq cursor_song3
jmp cursor_song4
cursor_song1:
lda #CHAR_CURSOR
sta SCREEN + (8 * 40) + 12
lda #CURSOR_COL
sta COLRAM + (8 * 40) + 12
rts
cursor_song2:
lda #CHAR_CURSOR
sta SCREEN + (10 * 40) + 12
lda #CURSOR_COL
sta COLRAM + (10 * 40) + 12
rts
cursor_song3:
lda #CHAR_CURSOR
sta SCREEN + (12 * 40) + 12
lda #CURSOR_COL
sta COLRAM + (12 * 40) + 12
rts
cursor_song4:
lda #CHAR_CURSOR
sta SCREEN + (14 * 40) + 12
lda #CURSOR_COL
sta COLRAM + (14 * 40) + 12
rts
; ----------------------------------------------------------------------------
; Update Menu State
; ----------------------------------------------------------------------------
update_menu:
; Handle key delay
lda key_delay_count
beq menu_check_input
dec key_delay_count
jmp menu_check_fire
menu_check_input:
; Check joystick up
lda CIA1_PRA
and #$01 ; Bit 0 = up
beq menu_up_pressed
; Check joystick down
lda CIA1_PRA
and #$02 ; Bit 1 = down
beq menu_down_pressed
; Check joystick left (difficulty)
lda CIA1_PRA
and #$04 ; Bit 2 = left
beq menu_left_pressed
; Check joystick right (difficulty)
lda CIA1_PRA
and #$08 ; Bit 3 = right
beq menu_right_pressed
jmp menu_check_fire
menu_up_pressed:
lda cursor_pos
beq menu_set_delay ; Already at top
dec cursor_pos
jsr play_menu_move
jsr draw_cursor
jmp menu_set_delay
menu_down_pressed:
lda cursor_pos
cmp #NUM_SONGS-1
bcs menu_set_delay ; Already at bottom
inc cursor_pos
jsr play_menu_move
jsr draw_cursor
jmp menu_set_delay
menu_left_pressed:
lda difficulty
beq menu_set_delay ; Already at Easy
dec difficulty
jsr play_menu_move
jsr draw_current_difficulty
jmp menu_set_delay
menu_right_pressed:
lda difficulty
cmp #DIFF_HARD
bcs menu_set_delay ; Already at Hard
inc difficulty
jsr play_menu_move
jsr draw_current_difficulty
jmp menu_set_delay
menu_set_delay:
lda #KEY_DELAY
sta key_delay_count
menu_check_keys:
; Check P key for practice toggle (row 1, column 5)
lda #$FD ; Row 1
sta CIA1_PRA
lda CIA1_PRB
and #$20 ; Column 5 = P
beq menu_p_pressed
; Check + key (row 0, column 0 = plus on keyboard)
lda #$FE ; Row 0
sta CIA1_PRA
lda CIA1_PRB
and #$01 ; Column 0 = +
beq menu_plus_pressed
; Check - key (row 5, column 3)
lda #$DF ; Row 5
sta CIA1_PRA
lda CIA1_PRB
and #$08 ; Column 3 = -
beq menu_minus_pressed
jmp menu_check_fire
menu_p_pressed:
; Toggle practice mode
lda practice_mode
eor #1
sta practice_mode
jsr play_menu_move
jsr draw_practice_state
lda #KEY_DELAY
sta key_delay_count
jmp menu_check_fire
menu_plus_pressed:
; Increase speed (towards 1.0x)
lda speed_setting
cmp #NUM_SPEEDS-1
bcs menu_check_fire ; Already at max
inc speed_setting
jsr play_menu_move
jsr draw_speed_state
lda #KEY_DELAY
sta key_delay_count
jmp menu_check_fire
menu_minus_pressed:
; Decrease speed (towards 0.5x)
lda speed_setting
beq menu_check_fire ; Already at min
dec speed_setting
jsr play_menu_move
jsr draw_speed_state
lda #KEY_DELAY
sta key_delay_count
menu_check_fire:
; Check for fire button
lda CIA1_PRA
and #$10
beq menu_fire_pressed
; Check space bar
lda #$7F
sta CIA1_PRA
lda CIA1_PRB
and #$10
beq menu_fire_pressed
lda #$FF
sta CIA1_PRA
rts
menu_fire_pressed:
lda #$FF
sta CIA1_PRA
; Play select sound
jsr play_menu_select
; Store selected song
lda cursor_pos
sta selected_song
; Set difficulty parameters
jsr set_difficulty_params
; Transition to game
jsr transition_to_game
rts
; ----------------------------------------------------------------------------
; Set Difficulty Parameters
; ----------------------------------------------------------------------------
set_difficulty_params:
lda difficulty
cmp #DIFF_EASY
beq set_diff_easy
cmp #DIFF_NORMAL
beq set_diff_normal
jmp set_diff_hard
set_diff_easy:
lda #PERFECT_WINDOW_EASY
sta perfect_window
lda #GOOD_WINDOW_EASY
sta good_window
lda #HEALTH_MISS_EASY
sta health_miss_amt
rts
set_diff_normal:
lda #PERFECT_WINDOW_NORMAL
sta perfect_window
lda #GOOD_WINDOW_NORMAL
sta good_window
lda #HEALTH_MISS_NORMAL
sta health_miss_amt
rts
set_diff_hard:
lda #PERFECT_WINDOW_HARD
sta perfect_window
lda #GOOD_WINDOW_HARD
sta good_window
lda #HEALTH_MISS_HARD
sta health_miss_amt
rts
; ----------------------------------------------------------------------------
; Transition to Game
; ----------------------------------------------------------------------------
transition_to_game:
; Set up tempo based on song selection
lda selected_song
beq setup_song1
cmp #1
beq setup_song2
cmp #2
beq setup_song3
jmp setup_song4
setup_song1:
lda #TEMPO_SONG1
sta frames_per_beat
lda #LENGTH_SONG1
sta song_length
; Select difficulty variant for Song 1
lda difficulty
cmp #DIFF_EASY
beq load_s1_easy
cmp #DIFF_NORMAL
beq load_s1_normal
jmp load_s1_hard
load_s1_easy:
lda #<song1_easy
sta song_data_ptr
lda #>song1_easy
sta song_data_ptr+1
jmp start_game
load_s1_normal:
lda #<song1_normal
sta song_data_ptr
lda #>song1_normal
sta song_data_ptr+1
jmp start_game
load_s1_hard:
lda #<song1_hard
sta song_data_ptr
lda #>song1_hard
sta song_data_ptr+1
jmp start_game
setup_song2:
lda #TEMPO_SONG2
sta frames_per_beat
lda #LENGTH_SONG2
sta song_length
; Select difficulty variant for Song 2
lda difficulty
cmp #DIFF_EASY
beq load_s2_easy
cmp #DIFF_NORMAL
beq load_s2_normal
jmp load_s2_hard
load_s2_easy:
lda #<song2_easy
sta song_data_ptr
lda #>song2_easy
sta song_data_ptr+1
jmp start_game
load_s2_normal:
lda #<song2_normal
sta song_data_ptr
lda #>song2_normal
sta song_data_ptr+1
jmp start_game
load_s2_hard:
lda #<song2_hard
sta song_data_ptr
lda #>song2_hard
sta song_data_ptr+1
jmp start_game
setup_song3:
lda #TEMPO_SONG3
sta frames_per_beat
lda #LENGTH_SONG3
sta song_length
; Select difficulty variant for Song 3
lda difficulty
cmp #DIFF_EASY
beq load_s3_easy
cmp #DIFF_NORMAL
beq load_s3_normal
jmp load_s3_hard
load_s3_easy:
lda #<song3_easy
sta song_data_ptr
lda #>song3_easy
sta song_data_ptr+1
jmp start_game
load_s3_normal:
lda #<song3_normal
sta song_data_ptr
lda #>song3_normal
sta song_data_ptr+1
jmp start_game
load_s3_hard:
lda #<song3_hard
sta song_data_ptr
lda #>song3_hard
sta song_data_ptr+1
jmp start_game
setup_song4:
lda #TEMPO_SONG4
sta frames_per_beat
lda #LENGTH_SONG4
sta song_length
; Select difficulty variant for Song 4
lda difficulty
cmp #DIFF_EASY
beq load_s4_easy
cmp #DIFF_NORMAL
beq load_s4_normal
jmp load_s4_hard
load_s4_easy:
lda #<song4_easy
sta song_data_ptr
lda #>song4_easy
sta song_data_ptr+1
jmp start_game
load_s4_normal:
lda #<song4_normal
sta song_data_ptr
lda #>song4_normal
sta song_data_ptr+1
jmp start_game
load_s4_hard:
lda #<song4_hard
sta song_data_ptr
lda #>song4_hard
sta song_data_ptr+1
start_game:
; Apply speed modifier to tempo
jsr apply_speed_modifier
; Initialise game
jsr init_game
lda #STATE_PLAYING
sta game_state
rts
; Apply speed modifier to frames_per_beat
apply_speed_modifier:
lda speed_setting
beq speed_half_tempo ; 0 = 0.5x
cmp #1
beq speed_3qrtr_tempo ; 1 = 0.75x
rts ; 2 = 1.0x, no change
speed_half_tempo:
; 0.5x speed = double frames_per_beat
asl frames_per_beat
rts
speed_3qrtr_tempo:
; 0.75x speed = frames_per_beat + frames_per_beat/3
; Approximation: add half (will be roughly 1.5x, close to 0.75x)
lda frames_per_beat
lsr ; Divide by 2
clc
adc frames_per_beat ; Add to original = 1.5x frames
sta frames_per_beat
rts
; Song data pointers
song_data_ptr:
!word 0
; ----------------------------------------------------------------------------
; Play Menu Move Sound
; ----------------------------------------------------------------------------
play_menu_move:
lda #0
sta SID_V3_FREQ_LO
lda #MENU_MOVE_FREQ
sta SID_V3_FREQ_HI
lda #$08
sta SID_V3_PWHI
lda #MENU_MOVE_AD
sta SID_V3_AD
lda #MENU_MOVE_SR
sta SID_V3_SR
lda #MENU_MOVE_WAVE
ora #$01 ; Gate on
sta SID_V3_CTRL
rts
; ----------------------------------------------------------------------------
; Play Menu Select Sound
; ----------------------------------------------------------------------------
play_menu_select:
lda #0
sta SID_V3_FREQ_LO
lda #MENU_SELECT_FREQ
sta SID_V3_FREQ_HI
lda #$08
sta SID_V3_PWHI
lda #MENU_SELECT_AD
sta SID_V3_AD
lda #MENU_SELECT_SR
sta SID_V3_SR
lda #MENU_SELECT_WAVE
ora #$01 ; Gate on
sta SID_V3_CTRL
rts
; ----------------------------------------------------------------------------
; Initialize Game
; ----------------------------------------------------------------------------
init_game:
jsr init_screen
jsr init_notes
jsr init_score
jsr init_health
jsr init_combo
jsr init_song
rts
; ----------------------------------------------------------------------------
; Initialize Combo
; ----------------------------------------------------------------------------
init_combo:
lda #0
sta combo
sta max_combo
jsr display_combo
rts
; ----------------------------------------------------------------------------
; Update Playing State
; ----------------------------------------------------------------------------
update_playing:
inc frame_count
lda frame_count
cmp frames_per_beat
bcc no_new_beat
lda #0
sta frame_count
jsr advance_song
jsr check_spawn_note
no_new_beat:
jsr update_notes
jsr reset_track_colours
jsr update_border_flash
jsr check_keys
jsr check_song_end
rts
; ----------------------------------------------------------------------------
; Update Results State
; ----------------------------------------------------------------------------
update_results:
; Check for fire to return to menu
lda CIA1_PRA
and #$10
beq results_fire
; Also check space bar
lda #$7F
sta CIA1_PRA
lda CIA1_PRB
and #$10
beq results_fire
lda #$FF
sta CIA1_PRA
rts
results_fire:
lda #$FF
sta CIA1_PRA
jsr play_menu_select
; Return to menu
jsr show_menu
lda #STATE_MENU
sta game_state
rts
; ----------------------------------------------------------------------------
; Update Game Over State
; ----------------------------------------------------------------------------
update_gameover:
; Check for fire to return to menu
lda CIA1_PRA
and #$10
beq gameover_fire
; Also check space bar
lda #$7F
sta CIA1_PRA
lda CIA1_PRB
and #$10
beq gameover_fire
lda #$FF
sta CIA1_PRA
rts
gameover_fire:
lda #$FF
sta CIA1_PRA
jsr play_menu_select
; Return to menu
jsr show_menu
lda #STATE_MENU
sta game_state
rts
; ----------------------------------------------------------------------------
; Initialize Screen (Gameplay)
; ----------------------------------------------------------------------------
init_screen:
; Enable custom charset
lda #$1C ; Character ROM at $3000
sta CHARPTR
; Set colours
lda #BORDER_COL
sta BORDER
lda #BG_COL
sta BGCOL
; Clear screen
ldx #0
lda #CHAR_SPACE
clear_screen:
sta SCREEN,x
sta SCREEN+$100,x
sta SCREEN+$200,x
sta SCREEN+$2E8,x
inx
bne clear_screen
; Draw tracks
ldx #0
draw_tracks:
lda #CHAR_TRACK
sta SCREEN + (TRACK1_ROW * 40),x
sta SCREEN + (TRACK2_ROW * 40),x
sta SCREEN + (TRACK3_ROW * 40),x
lda #TRACK_LINE_COL
sta COLRAM + (TRACK1_ROW * 40),x
sta COLRAM + (TRACK2_ROW * 40),x
sta COLRAM + (TRACK3_ROW * 40),x
inx
cpx #38
bne draw_tracks
; Draw hit zones
lda #CHAR_HITZONE
sta SCREEN + (TRACK1_ROW * 40) + HIT_ZONE_COLUMN
sta SCREEN + (TRACK2_ROW * 40) + HIT_ZONE_COLUMN
sta SCREEN + (TRACK3_ROW * 40) + HIT_ZONE_COLUMN
lda #HIT_ZONE_COL
sta COLRAM + (TRACK1_ROW * 40) + HIT_ZONE_COLUMN
sta COLRAM + (TRACK2_ROW * 40) + HIT_ZONE_COLUMN
sta COLRAM + (TRACK3_ROW * 40) + HIT_ZONE_COLUMN
; Draw track labels
lda #$31 ; "1"
sta SCREEN + (TRACK1_ROW * 40)
lda #$32 ; "2"
sta SCREEN + (TRACK2_ROW * 40)
lda #$33 ; "3"
sta SCREEN + (TRACK3_ROW * 40)
lda #1
sta COLRAM + (TRACK1_ROW * 40)
sta COLRAM + (TRACK2_ROW * 40)
sta COLRAM + (TRACK3_ROW * 40)
; Draw HUD labels
ldx #0
draw_score_label:
lda score_label,x
beq draw_miss_label_start
sta SCREEN,x
lda #7
sta COLRAM,x
inx
jmp draw_score_label
draw_miss_label_start:
ldx #0
draw_miss_label:
lda miss_label,x
beq draw_combo_label_start
sta SCREEN + 14,x
lda #2
sta COLRAM + 14,x
inx
jmp draw_miss_label
draw_combo_label_start:
ldx #0
draw_combo_label:
lda combo_label,x
beq draw_health_label_start
sta SCREEN + (COMBO_ROW * 40) + 27,x
lda #COMBO_COL
sta COLRAM + (COMBO_ROW * 40) + 27,x
inx
jmp draw_combo_label
draw_health_label_start:
ldx #0
draw_health_label:
lda health_label,x
beq draw_progress_label_start
sta SCREEN + (HEALTH_ROW * 40),x
lda #HEALTH_COL
sta COLRAM + (HEALTH_ROW * 40),x
inx
jmp draw_health_label
draw_progress_label_start:
ldx #0
draw_progress_label:
lda progress_label,x
beq labels_done
sta SCREEN + (PROGRESS_ROW * 40),x
lda #PROGRESS_COL
sta COLRAM + (PROGRESS_ROW * 40),x
inx
jmp draw_progress_label
labels_done:
; Draw song name based on selection
lda selected_song
beq draw_name_song1
jmp draw_name_song2
draw_name_song1:
ldx #0
draw_sn1:
lda song1_name,x
beq draw_difficulty_hud
sta SCREEN + 28,x
lda #11
sta COLRAM + 28,x
inx
jmp draw_sn1
draw_name_song2:
ldx #0
draw_sn2:
lda song2_name,x
beq draw_difficulty_hud
sta SCREEN + 26,x
lda #11
sta COLRAM + 26,x
inx
jmp draw_sn2
draw_difficulty_hud:
; Show difficulty on gameplay HUD
lda difficulty
cmp #DIFF_EASY
beq draw_hud_easy
cmp #DIFF_NORMAL
beq draw_hud_normal
jmp draw_hud_hard
draw_hud_easy:
ldx #0
draw_hud_e:
lda easy_text,x
beq draw_song_name_done
sta SCREEN + (COMBO_ROW * 40),x
lda #EASY_COL
sta COLRAM + (COMBO_ROW * 40),x
inx
jmp draw_hud_e
draw_hud_normal:
ldx #0
draw_hud_n:
lda normal_text,x
beq draw_song_name_done
sta SCREEN + (COMBO_ROW * 40),x
lda #NORMAL_COL
sta COLRAM + (COMBO_ROW * 40),x
inx
jmp draw_hud_n
draw_hud_hard:
ldx #0
draw_hud_h:
lda hard_text,x
beq draw_song_name_done
sta SCREEN + (COMBO_ROW * 40),x
lda #HARD_COL
sta COLRAM + (COMBO_ROW * 40),x
inx
jmp draw_hud_h
draw_song_name_done:
rts
score_label:
!scr "score:"
!byte 0
miss_label:
!scr "miss:"
!byte 0
combo_label:
!scr "combo:"
!byte 0
health_label:
!scr "health:"
!byte 0
progress_label:
!scr "song:"
!byte 0
; ----------------------------------------------------------------------------
; Initialize Notes
; ----------------------------------------------------------------------------
init_notes:
ldx #0
lda #0
clear_notes:
sta note_track,x
sta note_col,x
sta note_freq,x
inx
cpx #MAX_NOTES
bne clear_notes
rts
; ----------------------------------------------------------------------------
; Initialize Score
; ----------------------------------------------------------------------------
init_score:
lda #0
sta score_lo
sta score_hi
sta miss_count
sta perfect_count
sta good_count
jsr display_score
jsr display_misses
rts
; ----------------------------------------------------------------------------
; Initialize Health
; ----------------------------------------------------------------------------
init_health:
lda #HEALTH_START
sta health
jsr display_health
rts
; ----------------------------------------------------------------------------
; Initialize Song
; ----------------------------------------------------------------------------
init_song:
lda #0
sta frame_count
sta beat_count
sta song_beat
sta song_ended
; Point to selected song data
lda song_data_ptr
sta song_pos
lda song_data_ptr+1
sta song_pos_hi
jsr display_progress
rts
; ----------------------------------------------------------------------------
; Initialize SID
; ----------------------------------------------------------------------------
init_sid:
; Clear SID
ldx #$18
lda #0
clear_sid:
sta SID,x
dex
bpl clear_sid
; Set volume
lda #$0F
sta SID_VOLUME
; Set pulse widths
lda #PULSE_WIDTH
sta SID_V1_PWHI
sta SID_V2_PWHI
sta SID_V3_PWHI
; Set ADSR for all voices
lda #VOICE_AD
sta SID_V1_AD
sta SID_V2_AD
sta SID_V3_AD
lda #VOICE_SR
sta SID_V1_SR
sta SID_V2_SR
sta SID_V3_SR
rts
; ----------------------------------------------------------------------------
; Copy Custom Charset
; ----------------------------------------------------------------------------
copy_charset:
; Copy default ROM charset to RAM first
sei
lda #$33
sta $01
ldx #0
copy_rom_chars:
lda $D000,x
sta CHARSET,x
lda $D100,x
sta CHARSET+$100,x
lda $D200,x
sta CHARSET+$200,x
lda $D300,x
sta CHARSET+$300,x
lda $D400,x
sta CHARSET+$400,x
lda $D500,x
sta CHARSET+$500,x
lda $D600,x
sta CHARSET+$600,x
lda $D700,x
sta CHARSET+$700,x
inx
bne copy_rom_chars
lda #$37
sta $01
cli
; Now add custom characters
; Character 128 - Note (solid circle)
lda #%00111100
sta CHARSET + (128 * 8) + 0
lda #%01111110
sta CHARSET + (128 * 8) + 1
lda #%11111111
sta CHARSET + (128 * 8) + 2
lda #%11111111
sta CHARSET + (128 * 8) + 3
lda #%11111111
sta CHARSET + (128 * 8) + 4
lda #%11111111
sta CHARSET + (128 * 8) + 5
lda #%01111110
sta CHARSET + (128 * 8) + 6
lda #%00111100
sta CHARSET + (128 * 8) + 7
; Character 129 - Track line (dashes)
lda #%00000000
sta CHARSET + (129 * 8) + 0
lda #%00000000
sta CHARSET + (129 * 8) + 1
lda #%00000000
sta CHARSET + (129 * 8) + 2
lda #%11001100
sta CHARSET + (129 * 8) + 3
lda #%11001100
sta CHARSET + (129 * 8) + 4
lda #%00000000
sta CHARSET + (129 * 8) + 5
lda #%00000000
sta CHARSET + (129 * 8) + 6
lda #%00000000
sta CHARSET + (129 * 8) + 7
; Character 130 - Hit zone (vertical bars)
lda #%10000001
sta CHARSET + (130 * 8) + 0
lda #%10000001
sta CHARSET + (130 * 8) + 1
lda #%10000001
sta CHARSET + (130 * 8) + 2
lda #%10000001
sta CHARSET + (130 * 8) + 3
lda #%10000001
sta CHARSET + (130 * 8) + 4
lda #%10000001
sta CHARSET + (130 * 8) + 5
lda #%10000001
sta CHARSET + (130 * 8) + 6
lda #%10000001
sta CHARSET + (130 * 8) + 7
; Character 131 - Bar full (solid block)
lda #%11111111
sta CHARSET + (131 * 8) + 0
sta CHARSET + (131 * 8) + 1
sta CHARSET + (131 * 8) + 2
sta CHARSET + (131 * 8) + 3
sta CHARSET + (131 * 8) + 4
sta CHARSET + (131 * 8) + 5
sta CHARSET + (131 * 8) + 6
sta CHARSET + (131 * 8) + 7
; Character 132 - Bar empty (hollow block)
lda #%11111111
sta CHARSET + (132 * 8) + 0
lda #%10000001
sta CHARSET + (132 * 8) + 1
sta CHARSET + (132 * 8) + 2
sta CHARSET + (132 * 8) + 3
sta CHARSET + (132 * 8) + 4
sta CHARSET + (132 * 8) + 5
sta CHARSET + (132 * 8) + 6
lda #%11111111
sta CHARSET + (132 * 8) + 7
rts
; ----------------------------------------------------------------------------
; Advance Song
; ----------------------------------------------------------------------------
advance_song:
inc song_beat
jsr display_progress
rts
; ----------------------------------------------------------------------------
; Check Spawn Note
; ----------------------------------------------------------------------------
check_spawn_note:
; Check if song has ended
lda song_ended
bne spawn_done
; Get pointer to current position in song
lda song_pos
sta ZP_PTR
lda song_pos_hi
sta ZP_PTR_HI
; Read beat number
ldy #0
lda (ZP_PTR),y
; Check for end marker
cmp #$FF
beq song_end_marker
; Check if this beat matches
cmp song_beat
bne spawn_done
; Spawn this note
iny
lda (ZP_PTR),y ; Track
sta temp_track
iny
lda (ZP_PTR),y ; Frequency
; Find free note slot
ldx #0
find_slot:
lda note_track,x
beq found_slot
inx
cpx #MAX_NOTES
bne find_slot
jmp advance_song_ptr ; No free slot, skip note
found_slot:
lda temp_track
sta note_track,x
lda #NOTE_SPAWN_COL
sta note_col,x
ldy #2
lda (ZP_PTR),y
sta note_freq,x
jsr draw_note
advance_song_ptr:
; Move to next note in song
lda song_pos
clc
adc #3
sta song_pos
lda song_pos_hi
adc #0
sta song_pos_hi
; Check if there are more notes on this beat
jmp check_spawn_note
song_end_marker:
lda #1
sta song_ended
spawn_done:
rts
; ----------------------------------------------------------------------------
; Update Notes
; ----------------------------------------------------------------------------
update_notes:
ldx #0
update_notes_loop:
lda note_track,x
beq update_next_note
; Erase at old position
jsr erase_note
; Move note left
dec note_col,x
; Check if past hit zone (missed)
lda note_col,x
cmp #HIT_ZONE_START
bcs note_still_active
; Note was missed
lda note_track,x
sta miss_track
lda #0
sta note_track,x
jsr handle_miss
jmp update_next_note
note_still_active:
jsr draw_note
update_next_note:
inx
cpx #MAX_NOTES
bne update_notes_loop
rts
; ----------------------------------------------------------------------------
; Draw Note
; ----------------------------------------------------------------------------
draw_note:
lda note_track,x
cmp #1
beq draw_note_t1
cmp #2
beq draw_note_t2
jmp draw_note_t3
draw_note_t1:
lda note_col,x
clc
adc #<(SCREEN + TRACK1_ROW * 40)
sta ZP_PTR
lda #>(SCREEN + TRACK1_ROW * 40)
adc #0
sta ZP_PTR_HI
lda #CHAR_NOTE
ldy #0
sta (ZP_PTR),y
; Set colour
lda note_col,x
clc
adc #<(COLRAM + TRACK1_ROW * 40)
sta ZP_PTR
lda #>(COLRAM + TRACK1_ROW * 40)
adc #0
sta ZP_PTR_HI
lda #TRACK1_NOTE_COL
sta (ZP_PTR),y
rts
draw_note_t2:
lda note_col,x
clc
adc #<(SCREEN + TRACK2_ROW * 40)
sta ZP_PTR
lda #>(SCREEN + TRACK2_ROW * 40)
adc #0
sta ZP_PTR_HI
lda #CHAR_NOTE
ldy #0
sta (ZP_PTR),y
lda note_col,x
clc
adc #<(COLRAM + TRACK2_ROW * 40)
sta ZP_PTR
lda #>(COLRAM + TRACK2_ROW * 40)
adc #0
sta ZP_PTR_HI
lda #TRACK2_NOTE_COL
sta (ZP_PTR),y
rts
draw_note_t3:
lda note_col,x
clc
adc #<(SCREEN + TRACK3_ROW * 40)
sta ZP_PTR
lda #>(SCREEN + TRACK3_ROW * 40)
adc #0
sta ZP_PTR_HI
lda #CHAR_NOTE
ldy #0
sta (ZP_PTR),y
lda note_col,x
clc
adc #<(COLRAM + TRACK3_ROW * 40)
sta ZP_PTR
lda #>(COLRAM + TRACK3_ROW * 40)
adc #0
sta ZP_PTR_HI
lda #TRACK3_NOTE_COL
sta (ZP_PTR),y
rts
; ----------------------------------------------------------------------------
; Erase Note
; ----------------------------------------------------------------------------
erase_note:
lda note_track,x
cmp #1
beq erase_note_t1
cmp #2
beq erase_note_t2
jmp erase_note_t3
erase_note_t1:
lda note_col,x
clc
adc #<(SCREEN + TRACK1_ROW * 40)
sta ZP_PTR
lda #>(SCREEN + TRACK1_ROW * 40)
adc #0
sta ZP_PTR_HI
lda #CHAR_TRACK
ldy #0
sta (ZP_PTR),y
lda note_col,x
clc
adc #<(COLRAM + TRACK1_ROW * 40)
sta ZP_PTR
lda #>(COLRAM + TRACK1_ROW * 40)
adc #0
sta ZP_PTR_HI
lda #TRACK_LINE_COL
sta (ZP_PTR),y
rts
erase_note_t2:
lda note_col,x
clc
adc #<(SCREEN + TRACK2_ROW * 40)
sta ZP_PTR
lda #>(SCREEN + TRACK2_ROW * 40)
adc #0
sta ZP_PTR_HI
lda #CHAR_TRACK
ldy #0
sta (ZP_PTR),y
lda note_col,x
clc
adc #<(COLRAM + TRACK2_ROW * 40)
sta ZP_PTR
lda #>(COLRAM + TRACK2_ROW * 40)
adc #0
sta ZP_PTR_HI
lda #TRACK_LINE_COL
sta (ZP_PTR),y
rts
erase_note_t3:
lda note_col,x
clc
adc #<(SCREEN + TRACK3_ROW * 40)
sta ZP_PTR
lda #>(SCREEN + TRACK3_ROW * 40)
adc #0
sta ZP_PTR_HI
lda #CHAR_TRACK
ldy #0
sta (ZP_PTR),y
lda note_col,x
clc
adc #<(COLRAM + TRACK3_ROW * 40)
sta ZP_PTR
lda #>(COLRAM + TRACK3_ROW * 40)
adc #0
sta ZP_PTR_HI
lda #TRACK_LINE_COL
sta (ZP_PTR),y
rts
; ----------------------------------------------------------------------------
; Handle Miss
; ----------------------------------------------------------------------------
handle_miss:
jsr play_miss_sound
jsr break_combo
; In practice mode, don't decrease health
lda practice_mode
bne skip_health_loss
; Decrease health (using difficulty-adjusted amount)
lda health_miss_amt
jsr decrease_health
skip_health_loss:
; Flash border red
lda #MISS_COL
sta BORDER
lda #8
sta border_flash
; Flash the track where miss happened
lda miss_track
cmp #1
beq flash_miss_t1
cmp #2
beq flash_miss_t2
jmp flash_miss_t3
flash_miss_t1:
ldx #0
lda #MISS_COL
flash_m1_loop:
sta COLRAM + (TRACK1_ROW * 40),x
inx
cpx #38
bne flash_m1_loop
rts
flash_miss_t2:
ldx #0
lda #MISS_COL
flash_m2_loop:
sta COLRAM + (TRACK2_ROW * 40),x
inx
cpx #38
bne flash_m2_loop
rts
flash_miss_t3:
ldx #0
lda #MISS_COL
flash_m3_loop:
sta COLRAM + (TRACK3_ROW * 40),x
inx
cpx #38
bne flash_m3_loop
rts
; ----------------------------------------------------------------------------
; Play Miss Sound
; ----------------------------------------------------------------------------
play_miss_sound:
inc miss_count
jsr display_misses
lda #0
sta SID_V3_FREQ_LO
lda #MISS_FREQ
sta SID_V3_FREQ_HI
lda #MISS_AD
sta SID_V3_AD
lda #MISS_SR
sta SID_V3_SR
lda #MISS_WAVE
ora #$01
sta SID_V3_CTRL
rts
; ----------------------------------------------------------------------------
; Play Perfect Sound
; ----------------------------------------------------------------------------
play_perfect_sound:
lda #0
sta SID_V3_FREQ_LO
lda #PERFECT_SFX_FREQ
sta SID_V3_FREQ_HI
lda #PERFECT_SFX_AD
sta SID_V3_AD
lda #PERFECT_SFX_SR
sta SID_V3_SR
lda #PERFECT_SFX_WAVE
ora #$01
sta SID_V3_CTRL
rts
; ----------------------------------------------------------------------------
; Play Good Sound
; ----------------------------------------------------------------------------
play_good_sound:
lda #0
sta SID_V3_FREQ_LO
lda #GOOD_SFX_FREQ
sta SID_V3_FREQ_HI
lda #GOOD_SFX_AD
sta SID_V3_AD
lda #GOOD_SFX_SR
sta SID_V3_SR
lda #GOOD_SFX_WAVE
ora #$01
sta SID_V3_CTRL
rts
; ----------------------------------------------------------------------------
; Increase Health
; ----------------------------------------------------------------------------
increase_health:
clc
adc health
cmp #HEALTH_MAX
bcc health_ok
lda #HEALTH_MAX
health_ok:
sta health
jsr display_health
rts
; ----------------------------------------------------------------------------
; Decrease Health
; ----------------------------------------------------------------------------
decrease_health:
sta temp_track
lda health
sec
sbc temp_track
bcs health_not_zero
lda #0
health_not_zero:
sta health
jsr display_health
; Check for game over
lda health
bne no_game_over
jsr show_gameover
lda #STATE_GAMEOVER
sta game_state
no_game_over:
rts
; ----------------------------------------------------------------------------
; Display Health Bar
; ----------------------------------------------------------------------------
display_health:
; Calculate filled blocks (health / 4 = blocks, max 16)
lda health
lsr
lsr
sta temp_track
ldx #0
draw_health_bar:
cpx temp_track
bcs draw_empty_health
lda #CHAR_BAR_FULL
jmp store_health_char
draw_empty_health:
lda #CHAR_BAR_EMPTY
store_health_char:
sta SCREEN + (HEALTH_ROW * 40) + 8,x
lda #HEALTH_COL
sta COLRAM + (HEALTH_ROW * 40) + 8,x
inx
cpx #16
bne draw_health_bar
rts
; ----------------------------------------------------------------------------
; Display Progress Bar
; ----------------------------------------------------------------------------
display_progress:
; Calculate progress (song_beat / 4)
lda song_beat
lsr
lsr
sta temp_track
ldx #0
draw_progress_bar:
cpx temp_track
bcs draw_empty_progress
lda #CHAR_BAR_FULL
jmp store_progress_char
draw_empty_progress:
lda #CHAR_BAR_EMPTY
store_progress_char:
sta SCREEN + (PROGRESS_ROW * 40) + 8,x
lda #PROGRESS_COL
sta COLRAM + (PROGRESS_ROW * 40) + 8,x
inx
cpx #PROGRESS_WIDTH
bne draw_progress_bar
rts
; ----------------------------------------------------------------------------
; Combo System
; ----------------------------------------------------------------------------
increment_combo:
inc combo
lda combo
cmp max_combo
bcc combo_no_max
sta max_combo
combo_no_max:
jsr display_combo
rts
break_combo:
lda #0
sta combo
jsr display_combo
rts
display_combo:
; Display combo count
lda combo
ldx #0
combo_div_100:
cmp #100
bcc combo_done_100
sec
sbc #100
inx
jmp combo_div_100
combo_done_100:
pha
txa
ora #$30
sta SCREEN + (COMBO_ROW * 40) + 34
pla
ldx #0
combo_div_10:
cmp #10
bcc combo_done_10
sec
sbc #10
inx
jmp combo_div_10
combo_done_10:
pha
txa
ora #$30
sta SCREEN + (COMBO_ROW * 40) + 35
pla
ora #$30
sta SCREEN + (COMBO_ROW * 40) + 36
; Colour based on multiplier
jsr get_multiplier
cmp #1
beq combo_col_1x
cmp #2
beq combo_col_2x
cmp #3
beq combo_col_3x
jmp combo_col_4x
combo_col_1x:
lda #11 ; Grey
ldx #COMBO_BORDER_1 ; Dark grey border
jmp set_combo_col
combo_col_2x:
lda #7 ; Yellow
ldx #COMBO_BORDER_2 ; Green border
jmp set_combo_col
combo_col_3x:
lda #5 ; Green
ldx #COMBO_BORDER_3 ; Yellow border
jmp set_combo_col
combo_col_4x:
lda #1 ; White
ldx #COMBO_BORDER_4 ; Red border (fire!)
set_combo_col:
sta COLRAM + (COMBO_ROW * 40) + 34
sta COLRAM + (COMBO_ROW * 40) + 35
sta COLRAM + (COMBO_ROW * 40) + 36
; Update border colour for visual feedback
lda combo
beq reset_border ; No combo = black border
stx BORDER ; Set border to tier colour
rts
reset_border:
lda #COMBO_BORDER_0
sta BORDER
rts
get_multiplier:
lda combo
cmp #COMBO_TIER_4
bcs mult_4x
cmp #COMBO_TIER_3
bcs mult_3x
cmp #COMBO_TIER_2
bcs mult_2x
lda #1
rts
mult_2x:
lda #2
rts
mult_3x:
lda #3
rts
mult_4x:
lda #4
rts
; ----------------------------------------------------------------------------
; Reset Track Colours
; ----------------------------------------------------------------------------
reset_track_colours:
ldx #1 ; Start at column 1 (skip label)
reset_col_loop:
lda #TRACK_LINE_COL
sta COLRAM + (TRACK1_ROW * 40),x
sta COLRAM + (TRACK2_ROW * 40),x
sta COLRAM + (TRACK3_ROW * 40),x
inx
cpx #38
bne reset_col_loop
; Restore hit zone colours
lda #HIT_ZONE_COL
sta COLRAM + (TRACK1_ROW * 40) + HIT_ZONE_COLUMN
sta COLRAM + (TRACK2_ROW * 40) + HIT_ZONE_COLUMN
sta COLRAM + (TRACK3_ROW * 40) + HIT_ZONE_COLUMN
; Redraw notes with correct colours
ldx #0
redraw_loop:
lda note_track,x
beq redraw_next
jsr draw_note
redraw_next:
inx
cpx #MAX_NOTES
bne redraw_loop
rts
; ----------------------------------------------------------------------------
; Update Border Flash
; ----------------------------------------------------------------------------
update_border_flash:
lda border_flash
beq flash_done
dec border_flash
bne flash_done
lda #BORDER_COL
sta BORDER
flash_done:
rts
; ----------------------------------------------------------------------------
; Check Keys
; ----------------------------------------------------------------------------
check_keys:
lda #$FD
sta CIA1_PRA
lda CIA1_PRB
and #$10
bne check_x_key
lda #1
sta key_pressed
jsr check_hit
bcc check_x_key
jsr play_voice1_note
jsr flash_track1_hit
jsr award_points
check_x_key:
lda #$FB
sta CIA1_PRA
lda CIA1_PRB
and #$80
bne check_c_key
lda #2
sta key_pressed
jsr check_hit
bcc check_c_key
jsr play_voice2_note
jsr flash_track2_hit
jsr award_points
check_c_key:
lda #$FB
sta CIA1_PRA
lda CIA1_PRB
and #$10
bne check_keys_done
lda #3
sta key_pressed
jsr check_hit
bcc check_keys_done
jsr play_voice3_note
jsr flash_track3_hit
jsr award_points
check_keys_done:
lda #$FF
sta CIA1_PRA
rts
; ----------------------------------------------------------------------------
; Check Hit (with difficulty-adjusted timing windows)
; ----------------------------------------------------------------------------
check_hit:
ldx #0
check_hit_loop:
lda note_track,x
beq check_hit_next
cmp key_pressed
bne check_hit_next
; Check if note is in hittable range
lda note_col,x
cmp #HIT_ZONE_START
bcc check_hit_next
cmp #HIT_ZONE_END+1
bcs check_hit_next
; Note is hittable - determine quality based on distance from perfect
lda note_freq,x
sta hit_note_freq
; Calculate distance from perfect column
lda note_col,x
sec
sbc #PERFECT_COL_POS
bcs dist_positive
; Negative distance - make it positive
eor #$FF
clc
adc #1
dist_positive:
; A now contains absolute distance from perfect
; Check if within perfect window
cmp perfect_window
bcc hit_is_perfect
beq hit_is_perfect
; Check if within good window
cmp good_window
bcc hit_is_good
beq hit_is_good
; Outside good window but in hit zone - still counts as good
jmp hit_is_good
hit_is_perfect:
lda #2
sta hit_quality
jmp hit_found
hit_is_good:
lda #1
sta hit_quality
hit_found:
jsr erase_note
lda #0
sta note_track,x
sec
rts
check_hit_next:
inx
cpx #MAX_NOTES
bne check_hit_loop
lda #0
sta hit_quality
clc
rts
; ----------------------------------------------------------------------------
; Check Song End
; ----------------------------------------------------------------------------
check_song_end:
lda song_ended
beq not_ended
; Check if all notes cleared
ldx #0
check_notes_clear:
lda note_track,x
bne not_ended
inx
cpx #MAX_NOTES
bne check_notes_clear
; Add delay before results
inc end_delay
lda end_delay
cmp #END_DELAY_FRAMES
bcc not_ended
; Show results
jsr show_results
lda #STATE_RESULTS
sta game_state
not_ended:
rts
; ----------------------------------------------------------------------------
; Award Points
; ----------------------------------------------------------------------------
award_points:
jsr increment_combo
lda hit_quality
cmp #2
beq award_perfect
; Good hit
lda #GOOD_SCORE
jsr apply_multiplier
jsr add_score
inc good_count
; Play good sound effect
jsr play_good_sound
lda #GOOD_COL
sta BORDER
lda #4
sta border_flash
lda #HEALTH_GOOD
jsr increase_health
jmp award_done
award_perfect:
; Perfect hit
lda #PERFECT_SCORE
jsr apply_multiplier
jsr add_score
inc perfect_count
; Play perfect sound effect
jsr play_perfect_sound
lda #PERFECT_COL
sta BORDER
lda #6
sta border_flash
lda #HEALTH_PERFECT
jsr increase_health
award_done:
jsr display_score
rts
; ----------------------------------------------------------------------------
; Apply Multiplier
; ----------------------------------------------------------------------------
apply_multiplier:
sta base_score
jsr get_multiplier
sta current_mult
lda base_score
sta score_add_lo
lda #0
sta score_add_hi
lda current_mult
cmp #1
beq mult_done_apply
dec current_mult
mult_add_loop:
lda score_add_lo
clc
adc base_score
sta score_add_lo
lda score_add_hi
adc #0
sta score_add_hi
dec current_mult
bne mult_add_loop
mult_done_apply:
rts
base_score: !byte 0
current_mult: !byte 0
score_add_lo: !byte 0
score_add_hi: !byte 0
; ----------------------------------------------------------------------------
; Add Score
; ----------------------------------------------------------------------------
add_score:
lda score_lo
clc
adc score_add_lo
sta score_lo
lda score_hi
adc score_add_hi
sta score_hi
rts
; ----------------------------------------------------------------------------
; Display Score
; ----------------------------------------------------------------------------
display_score:
lda score_lo
sta work_lo
lda score_hi
sta work_hi
ldx #0
div_10000:
lda work_lo
sec
sbc #<10000
tay
lda work_hi
sbc #>10000
bcc done_10000
sta work_hi
sty work_lo
inx
jmp div_10000
done_10000:
txa
ora #$30
sta SCREEN + 8
ldx #0
div_1000:
lda work_lo
sec
sbc #<1000
tay
lda work_hi
sbc #>1000
bcc done_1000
sta work_hi
sty work_lo
inx
jmp div_1000
done_1000:
txa
ora #$30
sta SCREEN + 9
ldx #0
div_100:
lda work_lo
sec
sbc #100
bcc done_100
sta work_lo
inx
jmp div_100
done_100:
txa
ora #$30
sta SCREEN + 10
ldx #0
div_10:
lda work_lo
sec
sbc #10
bcc done_10
sta work_lo
inx
jmp div_10
done_10:
txa
ora #$30
sta SCREEN + 11
lda work_lo
ora #$30
sta SCREEN + 12
lda #7
sta COLRAM + 8
sta COLRAM + 9
sta COLRAM + 10
sta COLRAM + 11
sta COLRAM + 12
rts
; ----------------------------------------------------------------------------
; Display Misses
; ----------------------------------------------------------------------------
display_misses:
lda miss_count
ldx #0
miss_div_10:
cmp #10
bcc miss_done_10
sec
sbc #10
inx
jmp miss_div_10
miss_done_10:
pha
txa
ora #$30
sta SCREEN + 21
pla
ora #$30
sta SCREEN + 22
lda #2
sta COLRAM + 21
sta COLRAM + 22
rts
work_lo: !byte 0
work_hi: !byte 0
; ----------------------------------------------------------------------------
; Play Voices (for note playback)
; ----------------------------------------------------------------------------
play_voice1_note:
lda #0
sta SID_V1_FREQ_LO
lda hit_note_freq
sta SID_V1_FREQ_HI
lda #VOICE1_WAVE
ora #$01
sta SID_V1_CTRL
rts
play_voice2_note:
lda #0
sta SID_V2_FREQ_LO
lda hit_note_freq
sta SID_V2_FREQ_HI
lda #VOICE2_WAVE
ora #$01
sta SID_V2_CTRL
rts
play_voice3_note:
lda #0
sta SID_V3_FREQ_LO
lda hit_note_freq
sta SID_V3_FREQ_HI
lda #VOICE3_WAVE
ora #$01
sta SID_V3_CTRL
rts
; ----------------------------------------------------------------------------
; Flash Tracks
; ----------------------------------------------------------------------------
flash_track1_hit:
ldx #0
lda #HIT_COL
flash_t1h_loop:
sta COLRAM + (TRACK1_ROW * 40),x
inx
cpx #38
bne flash_t1h_loop
lda #1
sta COLRAM + (TRACK1_ROW * 40)
rts
flash_track2_hit:
ldx #0
lda #HIT_COL
flash_t2h_loop:
sta COLRAM + (TRACK2_ROW * 40),x
inx
cpx #38
bne flash_t2h_loop
lda #1
sta COLRAM + (TRACK2_ROW * 40)
rts
flash_track3_hit:
ldx #0
lda #HIT_COL
flash_t3h_loop:
sta COLRAM + (TRACK3_ROW * 40),x
inx
cpx #38
bne flash_t3h_loop
lda #1
sta COLRAM + (TRACK3_ROW * 40)
rts
; ----------------------------------------------------------------------------
; Show Results Screen
; ----------------------------------------------------------------------------
show_results:
; Clear screen
ldx #0
lda #CHAR_SPACE
clear_results:
sta SCREEN,x
sta SCREEN+$100,x
sta SCREEN+$200,x
sta SCREEN+$2E8,x
inx
bne clear_results
; Draw "SONG COMPLETE!"
ldx #0
draw_complete:
lda complete_text,x
beq draw_results_score
sta SCREEN + (5 * 40) + 13,x
lda #5
sta COLRAM + (5 * 40) + 13,x
inx
jmp draw_complete
draw_results_score:
; Draw score label
ldx #0
draw_rs_label:
lda results_score_label,x
beq draw_rs_value
sta SCREEN + (9 * 40) + 12,x
lda #7
sta COLRAM + (9 * 40) + 12,x
inx
jmp draw_rs_label
draw_rs_value:
; Draw score value
lda score_lo
sta work_lo
lda score_hi
sta work_hi
ldx #0
rs_div_10000:
lda work_lo
sec
sbc #<10000
tay
lda work_hi
sbc #>10000
bcc rs_done_10000
sta work_hi
sty work_lo
inx
jmp rs_div_10000
rs_done_10000:
txa
ora #$30
sta SCREEN + (9 * 40) + 23
ldx #0
rs_div_1000:
lda work_lo
sec
sbc #<1000
tay
lda work_hi
sbc #>1000
bcc rs_done_1000
sta work_hi
sty work_lo
inx
jmp rs_div_1000
rs_done_1000:
txa
ora #$30
sta SCREEN + (9 * 40) + 24
ldx #0
rs_div_100:
lda work_lo
sec
sbc #100
bcc rs_done_100
sta work_lo
inx
jmp rs_div_100
rs_done_100:
txa
ora #$30
sta SCREEN + (9 * 40) + 25
ldx #0
rs_div_10:
lda work_lo
sec
sbc #10
bcc rs_done_10
sta work_lo
inx
jmp rs_div_10
rs_done_10:
txa
ora #$30
sta SCREEN + (9 * 40) + 26
lda work_lo
ora #$30
sta SCREEN + (9 * 40) + 27
lda #7
sta COLRAM + (9 * 40) + 23
sta COLRAM + (9 * 40) + 24
sta COLRAM + (9 * 40) + 25
sta COLRAM + (9 * 40) + 26
sta COLRAM + (9 * 40) + 27
; Draw perfect count
ldx #0
draw_perfect_label:
lda perfect_label,x
beq draw_perfect_value
sta SCREEN + (11 * 40) + 12,x
lda #1
sta COLRAM + (11 * 40) + 12,x
inx
jmp draw_perfect_label
draw_perfect_value:
lda perfect_count
ldx #0
pv_div_10:
cmp #10
bcc pv_done_10
sec
sbc #10
inx
jmp pv_div_10
pv_done_10:
pha
txa
ora #$30
sta SCREEN + (11 * 40) + 23
pla
ora #$30
sta SCREEN + (11 * 40) + 24
lda #1
sta COLRAM + (11 * 40) + 23
sta COLRAM + (11 * 40) + 24
; Draw good count
ldx #0
draw_good_label:
lda good_label,x
beq draw_good_value
sta SCREEN + (12 * 40) + 12,x
lda #7
sta COLRAM + (12 * 40) + 12,x
inx
jmp draw_good_label
draw_good_value:
lda good_count
ldx #0
gv_div_10:
cmp #10
bcc gv_done_10
sec
sbc #10
inx
jmp gv_div_10
gv_done_10:
pha
txa
ora #$30
sta SCREEN + (12 * 40) + 23
pla
ora #$30
sta SCREEN + (12 * 40) + 24
lda #7
sta COLRAM + (12 * 40) + 23
sta COLRAM + (12 * 40) + 24
; Draw miss count
ldx #0
draw_miss_label_r:
lda miss_label_r,x
beq draw_miss_value
sta SCREEN + (13 * 40) + 12,x
lda #2
sta COLRAM + (13 * 40) + 12,x
inx
jmp draw_miss_label_r
draw_miss_value:
lda miss_count
ldx #0
mv_div_10:
cmp #10
bcc mv_done_10
sec
sbc #10
inx
jmp mv_div_10
mv_done_10:
pha
txa
ora #$30
sta SCREEN + (13 * 40) + 23
pla
ora #$30
sta SCREEN + (13 * 40) + 24
lda #2
sta COLRAM + (13 * 40) + 23
sta COLRAM + (13 * 40) + 24
; Draw max combo
ldx #0
draw_maxc_label:
lda maxcombo_label,x
beq draw_maxc_value
sta SCREEN + (15 * 40) + 12,x
lda #COMBO_COL
sta COLRAM + (15 * 40) + 12,x
inx
jmp draw_maxc_label
draw_maxc_value:
lda max_combo
ldx #0
mc_div_100:
cmp #100
bcc mc_done_100
sec
sbc #100
inx
jmp mc_div_100
mc_done_100:
pha
txa
ora #$30
sta SCREEN + (15 * 40) + 23
pla
ldx #0
mc_div_10:
cmp #10
bcc mc_done_10
sec
sbc #10
inx
jmp mc_div_10
mc_done_10:
pha
txa
ora #$30
sta SCREEN + (15 * 40) + 24
pla
ora #$30
sta SCREEN + (15 * 40) + 25
lda #COMBO_COL
sta COLRAM + (15 * 40) + 23
sta COLRAM + (15 * 40) + 24
sta COLRAM + (15 * 40) + 25
; Draw "PRESS FIRE"
ldx #0
draw_return:
lda return_text,x
beq results_done
sta SCREEN + (20 * 40) + 10,x
lda #11
sta COLRAM + (20 * 40) + 10,x
inx
jmp draw_return
results_done:
rts
complete_text:
!scr "song complete!"
!byte 0
results_score_label:
!scr "final score:"
!byte 0
perfect_label:
!scr "perfect:"
!byte 0
good_label:
!scr "good:"
!byte 0
miss_label_r:
!scr "misses:"
!byte 0
maxcombo_label:
!scr "max combo:"
!byte 0
return_text:
!scr "press fire to continue"
!byte 0
; ----------------------------------------------------------------------------
; Show Game Over Screen
; ----------------------------------------------------------------------------
show_gameover:
; Clear screen
ldx #0
lda #CHAR_SPACE
clear_gameover:
sta SCREEN,x
sta SCREEN+$100,x
sta SCREEN+$200,x
sta SCREEN+$2E8,x
inx
bne clear_gameover
; Draw "GAME OVER"
ldx #0
draw_gameover_text:
lda gameover_text,x
beq draw_gameover_score
sta SCREEN + (8 * 40) + 15,x
lda #2
sta COLRAM + (8 * 40) + 15,x
inx
jmp draw_gameover_text
draw_gameover_score:
; Draw score
ldx #0
draw_go_score_label:
lda gameover_score,x
beq draw_go_score_value
sta SCREEN + (12 * 40) + 12,x
lda #7
sta COLRAM + (12 * 40) + 12,x
inx
jmp draw_go_score_label
draw_go_score_value:
lda score_lo
sta work_lo
lda score_hi
sta work_hi
ldx #0
go_div_10000:
lda work_lo
sec
sbc #<10000
tay
lda work_hi
sbc #>10000
bcc go_done_10000
sta work_hi
sty work_lo
inx
jmp go_div_10000
go_done_10000:
txa
ora #$30
sta SCREEN + (12 * 40) + 23
ldx #0
go_div_1000:
lda work_lo
sec
sbc #<1000
tay
lda work_hi
sbc #>1000
bcc go_done_1000
sta work_hi
sty work_lo
inx
jmp go_div_1000
go_done_1000:
txa
ora #$30
sta SCREEN + (12 * 40) + 24
ldx #0
go_div_100:
lda work_lo
sec
sbc #100
bcc go_done_100
sta work_lo
inx
jmp go_div_100
go_done_100:
txa
ora #$30
sta SCREEN + (12 * 40) + 25
ldx #0
go_div_10:
lda work_lo
sec
sbc #10
bcc go_done_10
sta work_lo
inx
jmp go_div_10
go_done_10:
txa
ora #$30
sta SCREEN + (12 * 40) + 26
lda work_lo
ora #$30
sta SCREEN + (12 * 40) + 27
lda #7
sta COLRAM + (12 * 40) + 23
sta COLRAM + (12 * 40) + 24
sta COLRAM + (12 * 40) + 25
sta COLRAM + (12 * 40) + 26
sta COLRAM + (12 * 40) + 27
; Draw retry message
ldx #0
draw_retry:
lda retry_text,x
beq gameover_done
sta SCREEN + (18 * 40) + 10,x
lda #11
sta COLRAM + (18 * 40) + 10,x
inx
jmp draw_retry
gameover_done:
rts
gameover_text:
!scr "game over"
!byte 0
gameover_score:
!scr "your score:"
!byte 0
retry_text:
!scr "press fire to continue"
!byte 0
; ============================================================================
; SONG 1 DATA - "First Steps" (120 BPM) - Three Difficulty Variants
; ============================================================================
; Easy: Notes only on strong beats (0, 8, 16, 24...) - 8 notes
; Normal: Base pattern - 29 notes
; Hard: Dense pattern with off-beat additions - 45 notes
; --- EASY: Sparse pattern (strong beats only) ---
song1_easy:
!byte 0, 1, $47 ; Beat 0
!byte 8, 2, $27 ; Beat 8
!byte 16, 1, $35 ; Beat 16
!byte 24, 3, $11 ; Beat 24
!byte 32, 2, $2F ; Beat 32
!byte 40, 1, $58 ; Beat 40
!byte 48, 3, $1A ; Beat 48
!byte 56, 1, $47 ; Beat 56
!byte $FF
; --- NORMAL: Base pattern ---
song1_normal:
!byte 0, 1, $47
!byte 2, 2, $2C
!byte 4, 3, $11
!byte 8, 1, $3B
!byte 10, 2, $27
!byte 12, 3, $13
!byte 16, 1, $35
!byte 17, 2, $2C
!byte 18, 1, $3B
!byte 20, 3, $16
!byte 24, 1, $47
!byte 26, 2, $35
!byte 28, 3, $11
!byte 32, 2, $2F
!byte 34, 1, $4F
!byte 36, 3, $17
!byte 40, 1, $58
!byte 42, 2, $2C
!byte 44, 3, $11
!byte 46, 2, $27
!byte 48, 1, $6A
!byte 49, 2, $35
!byte 50, 1, $58
!byte 52, 3, $1A
!byte 54, 2, $2F
!byte 56, 1, $47
!byte 58, 2, $2C
!byte 60, 3, $11
!byte 62, 1, $35
!byte $FF
; --- HARD: Dense pattern (added off-beats) ---
song1_hard:
!byte 0, 1, $47
!byte 1, 3, $16 ; Added
!byte 2, 2, $2C
!byte 3, 1, $35 ; Added
!byte 4, 3, $11
!byte 5, 2, $27 ; Added
!byte 6, 1, $3B ; Added
!byte 8, 1, $3B
!byte 9, 3, $13 ; Added
!byte 10, 2, $27
!byte 11, 1, $35 ; Added
!byte 12, 3, $13
!byte 14, 2, $2C ; Added
!byte 16, 1, $35
!byte 17, 2, $2C
!byte 18, 1, $3B
!byte 19, 3, $11 ; Added
!byte 20, 3, $16
!byte 21, 1, $47 ; Added
!byte 22, 2, $35 ; Added
!byte 24, 1, $47
!byte 25, 3, $16 ; Added
!byte 26, 2, $35
!byte 27, 1, $4F ; Added
!byte 28, 3, $11
!byte 30, 2, $27 ; Added
!byte 32, 2, $2F
!byte 33, 1, $47 ; Added
!byte 34, 1, $4F
!byte 35, 3, $11 ; Added
!byte 36, 3, $17
!byte 38, 2, $2C ; Added
!byte 40, 1, $58
!byte 41, 3, $1A ; Added
!byte 42, 2, $2C
!byte 43, 1, $47 ; Added
!byte 44, 3, $11
!byte 45, 2, $35 ; Added
!byte 46, 2, $27
!byte 47, 1, $4F ; Added
!byte 48, 1, $6A
!byte 49, 2, $35
!byte 50, 1, $58
!byte 51, 3, $16 ; Added
!byte 52, 3, $1A
!byte 53, 1, $47 ; Added
!byte 54, 2, $2F
!byte 55, 3, $11 ; Added
!byte 56, 1, $47
!byte 57, 2, $27 ; Added
!byte 58, 2, $2C
!byte 59, 1, $3B ; Added
!byte 60, 3, $11
!byte 61, 2, $35 ; Added
!byte 62, 1, $35
!byte 63, 3, $16 ; Added
!byte $FF
; ============================================================================
; SONG 2 DATA - "Upbeat Groove" (130 BPM) - Three Difficulty Variants
; ============================================================================
; Easy: Notes only on strong beats - 8 notes
; Normal: Base syncopated pattern - 52 notes
; Hard: Extremely dense pattern - 72 notes
; --- EASY: Sparse pattern (strong beats only) ---
song2_easy:
!byte 0, 1, $47 ; Beat 0
!byte 8, 3, $11 ; Beat 8
!byte 16, 1, $4F ; Beat 16
!byte 24, 2, $47 ; Beat 24
!byte 32, 1, $4F ; Beat 32
!byte 40, 3, $1A ; Beat 40
!byte 48, 3, $11 ; Beat 48
!byte 56, 1, $47 ; Beat 56
!byte $FF
; --- NORMAL: Base syncopated pattern ---
song2_normal:
!byte 0, 1, $47
!byte 1, 2, $35
!byte 3, 3, $16
!byte 4, 1, $4F
!byte 5, 2, $2C
!byte 7, 1, $47
!byte 8, 3, $11
!byte 10, 2, $35
!byte 11, 1, $58
!byte 13, 2, $2C
!byte 14, 3, $1A
!byte 15, 1, $47
!byte 16, 1, $4F
!byte 17, 2, $35
!byte 18, 3, $16
!byte 19, 1, $58
!byte 20, 2, $2C
!byte 22, 1, $6A
!byte 23, 2, $35
!byte 24, 3, $11
!byte 25, 1, $58
!byte 26, 2, $47
!byte 28, 3, $1A
!byte 30, 1, $47
!byte 31, 2, $2C
!byte 32, 1, $4F
!byte 33, 3, $16
!byte 34, 2, $35
!byte 35, 1, $58
!byte 36, 3, $11
!byte 37, 1, $6A
!byte 38, 2, $47
!byte 39, 1, $58
!byte 40, 3, $1A
!byte 41, 2, $35
!byte 42, 1, $4F
!byte 43, 2, $2C
!byte 44, 1, $47
!byte 45, 3, $16
!byte 46, 2, $35
!byte 47, 1, $58
!byte 48, 3, $11
!byte 49, 2, $47
!byte 51, 1, $4F
!byte 52, 3, $1A
!byte 54, 2, $35
!byte 55, 1, $47
!byte 56, 3, $11
!byte 58, 2, $2C
!byte 59, 1, $58
!byte 60, 3, $16
!byte 61, 2, $35
!byte 62, 1, $47
!byte $FF
; --- HARD: Extremely dense pattern ---
song2_hard:
!byte 0, 1, $47
!byte 0, 3, $11 ; Chord
!byte 1, 2, $35
!byte 2, 1, $4F ; Added
!byte 3, 3, $16
!byte 4, 1, $4F
!byte 4, 2, $2C ; Chord
!byte 5, 2, $2C
!byte 6, 3, $1A ; Added
!byte 7, 1, $47
!byte 8, 3, $11
!byte 8, 1, $58 ; Chord
!byte 9, 2, $35 ; Added
!byte 10, 2, $35
!byte 11, 1, $58
!byte 12, 3, $16 ; Added
!byte 13, 2, $2C
!byte 14, 3, $1A
!byte 15, 1, $47
!byte 16, 1, $4F
!byte 16, 3, $11 ; Chord
!byte 17, 2, $35
!byte 18, 3, $16
!byte 19, 1, $58
!byte 20, 2, $2C
!byte 20, 1, $47 ; Chord
!byte 21, 3, $1A ; Added
!byte 22, 1, $6A
!byte 23, 2, $35
!byte 24, 3, $11
!byte 24, 1, $4F ; Chord
!byte 25, 1, $58
!byte 26, 2, $47
!byte 27, 3, $16 ; Added
!byte 28, 3, $1A
!byte 28, 1, $58 ; Chord
!byte 29, 2, $35 ; Added
!byte 30, 1, $47
!byte 31, 2, $2C
!byte 32, 1, $4F
!byte 32, 3, $11 ; Chord
!byte 33, 3, $16
!byte 34, 2, $35
!byte 35, 1, $58
!byte 36, 3, $11
!byte 36, 2, $47 ; Chord
!byte 37, 1, $6A
!byte 38, 2, $47
!byte 39, 1, $58
!byte 40, 3, $1A
!byte 40, 1, $4F ; Chord
!byte 41, 2, $35
!byte 42, 1, $4F
!byte 43, 2, $2C
!byte 44, 1, $47
!byte 44, 3, $11 ; Chord
!byte 45, 3, $16
!byte 46, 2, $35
!byte 47, 1, $58
!byte 48, 3, $11
!byte 48, 1, $6A ; Chord
!byte 49, 2, $47
!byte 50, 1, $58 ; Added
!byte 51, 1, $4F
!byte 52, 3, $1A
!byte 52, 2, $35 ; Chord
!byte 53, 1, $47 ; Added
!byte 54, 2, $35
!byte 55, 1, $47
!byte 56, 3, $11
!byte 56, 1, $4F ; Chord
!byte 57, 2, $47 ; Added
!byte 58, 2, $2C
!byte 59, 1, $58
!byte 60, 3, $16
!byte 60, 1, $47 ; Chord
!byte 61, 2, $35
!byte 62, 1, $47
!byte 63, 3, $11 ; Added
!byte $FF
; ============================================================================
; SONG 3 DATA: "Speed Rush" (150 BPM)
; ============================================================================
; An energetic, fast-paced track designed to test reaction time.
; Higher frequencies and rapid note sequences.
; --- EASY: Strong beats only (8 notes) ---
song3_easy:
!byte 0, 1, $58 ; Beat 0
!byte 8, 2, $35 ; Beat 8
!byte 16, 3, $1A ; Beat 16
!byte 24, 1, $6A ; Beat 24
!byte 32, 2, $47 ; Beat 32
!byte 40, 3, $16 ; Beat 40
!byte 48, 1, $58 ; Beat 48
!byte 56, 2, $35 ; Beat 56
!byte $FF
; --- NORMAL: Base pattern (32 notes) ---
song3_normal:
!byte 0, 1, $58
!byte 2, 2, $35
!byte 4, 3, $1A
!byte 6, 1, $6A
!byte 8, 2, $35
!byte 10, 1, $58
!byte 12, 3, $16
!byte 14, 2, $47
!byte 16, 3, $1A
!byte 18, 1, $6A
!byte 20, 2, $35
!byte 22, 3, $16
!byte 24, 1, $6A
!byte 26, 2, $47
!byte 28, 3, $1A
!byte 30, 1, $58
!byte 32, 2, $47
!byte 34, 1, $58
!byte 36, 3, $16
!byte 38, 2, $35
!byte 40, 3, $16
!byte 42, 1, $6A
!byte 44, 2, $47
!byte 46, 3, $1A
!byte 48, 1, $58
!byte 50, 2, $35
!byte 52, 3, $16
!byte 54, 1, $6A
!byte 56, 2, $35
!byte 58, 3, $1A
!byte 60, 1, $58
!byte 62, 2, $47
!byte $FF
; --- HARD: Dense pattern with rapid-fire sections (56 notes) ---
song3_hard:
!byte 0, 1, $58
!byte 1, 3, $1A ; Added
!byte 2, 2, $35
!byte 3, 1, $6A ; Added
!byte 4, 3, $1A
!byte 5, 2, $47 ; Added
!byte 6, 1, $6A
!byte 7, 3, $16 ; Added
!byte 8, 2, $35
!byte 9, 1, $58 ; Added
!byte 10, 1, $58
!byte 11, 2, $35 ; Added
!byte 12, 3, $16
!byte 13, 1, $6A ; Added
!byte 14, 2, $47
!byte 15, 3, $1A ; Added
!byte 16, 3, $1A
!byte 17, 1, $58 ; Added
!byte 18, 1, $6A
!byte 19, 2, $35 ; Added
!byte 20, 2, $35
!byte 21, 3, $16 ; Added
!byte 22, 3, $16
!byte 23, 1, $58 ; Added
!byte 24, 1, $6A
!byte 25, 2, $47 ; Added
!byte 26, 2, $47
!byte 27, 3, $1A ; Added
!byte 28, 3, $1A
!byte 29, 1, $6A ; Added
!byte 30, 1, $58
!byte 31, 2, $35 ; Added
!byte 32, 2, $47
!byte 33, 3, $16 ; Added
!byte 34, 1, $58
!byte 35, 2, $47 ; Added
!byte 36, 3, $16
!byte 37, 1, $6A ; Added
!byte 38, 2, $35
!byte 39, 3, $1A ; Added
!byte 40, 3, $16
!byte 41, 1, $58 ; Added
!byte 42, 1, $6A
!byte 43, 2, $35 ; Added
!byte 44, 2, $47
!byte 45, 3, $16 ; Added
!byte 46, 3, $1A
!byte 47, 1, $6A ; Added
!byte 48, 1, $58
!byte 49, 2, $47 ; Added
!byte 50, 2, $35
!byte 51, 3, $1A ; Added
!byte 52, 3, $16
!byte 53, 1, $58 ; Added
!byte 54, 1, $6A
!byte 55, 2, $35 ; Added
!byte 56, 2, $35
!byte 57, 3, $16 ; Added
!byte 58, 3, $1A
!byte 59, 1, $6A ; Added
!byte 60, 1, $58
!byte 61, 2, $47 ; Added
!byte 62, 2, $47
!byte 63, 3, $1A ; Added
!byte $FF
; ============================================================================
; SONG 4: "Off-Beat" (125 BPM) - Syncopated rhythms
; ============================================================================
; Syncopation emphasises off-beats. Notes land between expected beats,
; challenging players' sense of rhythm. The pattern feels "pushed" forward.
; --- EASY: Sparse syncopated notes (10 notes) ---
; Only the most prominent off-beat accents
song4_easy:
!byte 1, 1, $47 ; Off-beat accent
!byte 9, 2, $3B ; Pushed note
!byte 17, 3, $27 ; Syncopated hit
!byte 25, 1, $47 ; Off-beat
!byte 33, 2, $3B ; Pushed
!byte 41, 3, $27 ; Syncopated
!byte 49, 1, $47 ; Off-beat
!byte 55, 2, $3B ; Pushed
!byte 59, 3, $27 ; Syncopated
!byte 63, 1, $47 ; Final accent
!byte $FF
; --- NORMAL: Syncopated pattern with anchors (32 notes) ---
; Mix of on-beat anchors and off-beat accents
song4_normal:
!byte 0, 1, $47 ; Anchor
!byte 1, 2, $3B ; Off-beat
!byte 3, 3, $27 ; Syncopated
!byte 4, 1, $47 ; Anchor
!byte 5, 2, $3B ; Off-beat
!byte 7, 3, $27 ; Syncopated
!byte 8, 1, $47 ; Anchor
!byte 9, 2, $3B ; Off-beat
!byte 11, 3, $27 ; Syncopated
!byte 12, 1, $47 ; Anchor
!byte 13, 2, $3B ; Off-beat
!byte 15, 3, $27 ; Syncopated
!byte 16, 1, $47 ; Anchor
!byte 17, 2, $3B ; Off-beat
!byte 19, 3, $27 ; Syncopated
!byte 20, 1, $47 ; Anchor
!byte 21, 2, $3B ; Off-beat
!byte 23, 3, $27 ; Syncopated
!byte 24, 1, $47 ; Anchor
!byte 25, 2, $3B ; Off-beat
!byte 27, 3, $27 ; Syncopated
!byte 28, 1, $47 ; Anchor
!byte 29, 2, $3B ; Off-beat
!byte 31, 3, $27 ; Syncopated
!byte 32, 1, $47 ; Anchor
!byte 33, 2, $3B ; Off-beat
!byte 35, 3, $27 ; Syncopated
!byte 40, 1, $47 ; Anchor
!byte 41, 2, $3B ; Off-beat
!byte 48, 1, $47 ; Anchor
!byte 49, 3, $27 ; Off-beat
!byte 56, 1, $47 ; Final anchor
!byte $FF
; --- HARD: Dense syncopated chaos (56 notes) ---
; Nearly every off-beat filled, minimal anchors
song4_hard:
!byte 0, 1, $47 ; Anchor
!byte 1, 2, $3B ; Off-beat
!byte 1, 3, $27 ; Chord
!byte 3, 1, $47 ; Syncopated
!byte 3, 2, $3B ; Chord
!byte 5, 3, $27 ; Off-beat
!byte 5, 1, $47 ; Chord
!byte 7, 2, $3B ; Syncopated
!byte 7, 3, $27 ; Chord
!byte 8, 1, $47 ; Anchor
!byte 9, 2, $3B ; Off-beat
!byte 9, 3, $27 ; Chord
!byte 11, 1, $47 ; Syncopated
!byte 11, 2, $3B ; Chord
!byte 13, 3, $27 ; Off-beat
!byte 13, 1, $47 ; Chord
!byte 15, 2, $3B ; Syncopated
!byte 15, 3, $27 ; Chord
!byte 16, 1, $47 ; Anchor
!byte 17, 2, $3B ; Off-beat
!byte 17, 3, $27 ; Chord
!byte 19, 1, $47 ; Syncopated
!byte 19, 2, $3B ; Chord
!byte 21, 3, $27 ; Off-beat
!byte 21, 1, $47 ; Chord
!byte 23, 2, $3B ; Syncopated
!byte 23, 3, $27 ; Chord
!byte 24, 1, $47 ; Anchor
!byte 25, 2, $3B ; Off-beat
!byte 25, 3, $27 ; Chord
!byte 27, 1, $47 ; Syncopated
!byte 27, 2, $3B ; Chord
!byte 29, 3, $27 ; Off-beat
!byte 29, 1, $47 ; Chord
!byte 31, 2, $3B ; Syncopated
!byte 31, 3, $27 ; Chord
!byte 32, 1, $47 ; Anchor
!byte 33, 2, $3B ; Off-beat
!byte 35, 3, $27 ; Syncopated
!byte 37, 1, $47 ; Off-beat
!byte 39, 2, $3B ; Syncopated
!byte 40, 1, $47 ; Anchor
!byte 41, 3, $27 ; Off-beat
!byte 43, 2, $3B ; Syncopated
!byte 45, 1, $47 ; Off-beat
!byte 47, 3, $27 ; Syncopated
!byte 48, 1, $47 ; Anchor
!byte 49, 2, $3B ; Off-beat
!byte 51, 3, $27 ; Syncopated
!byte 53, 1, $47 ; Off-beat
!byte 55, 2, $3B ; Syncopated
!byte 56, 1, $47 ; Anchor
!byte 57, 3, $27 ; Off-beat
!byte 59, 2, $3B ; Syncopated
!byte 61, 1, $47 ; Off-beat
!byte 63, 3, $27 ; Final syncopated
!byte $FF
; ----------------------------------------------------------------------------
; Note Arrays
; ----------------------------------------------------------------------------
note_track:
!fill MAX_NOTES, 0
note_col:
!fill MAX_NOTES, 0
note_freq:
!fill MAX_NOTES, 0
; ----------------------------------------------------------------------------
; Game Variables
; ----------------------------------------------------------------------------
score_lo: !byte 0
score_hi: !byte 0
miss_count: !byte 0
perfect_count: !byte 0
good_count: !byte 0
health: !byte 0
combo: !byte 0
max_combo: !byte 0
; ============================================================================
; END OF SID SYMPHONY - UNIT 19
; ============================================================================
What’s Coming
With syncopation introducing rhythmic complexity:
- Unit 25: High score persistence
- Unit 26: Song 5 with complex patterns
- Unit 27: Visual polish and effects
What You’ve Learnt
- Syncopation - Emphasising off-beats creates rhythmic tension
- Anchor notes - Strong beat markers help orient players
- Tempo selection - 125 BPM balances challenge and playability
- Pattern design - Off-beat placement creates distinctive feel
- Menu scaling - Cursor and selection logic extends to N songs
Song 4 challenges players to break their assumptions about where notes should land.
What Changed
Unit 23 → Unit 24
+208-8
| 1 | 1 | ; ============================================================================ | |
| 2 | - | ; SID SYMPHONY - Unit 23: Practice Mode | |
| 2 | + | ; SID SYMPHONY - Unit 24: Song 4 - Syncopation | |
| 3 | 3 | ; ============================================================================ | |
| 4 | - | ; A no-fail mode for learning songs. Health never depletes, allowing players | |
| 5 | - | ; to practice difficult sections without frustration. Speed can be adjusted | |
| 6 | - | ; to 0.5x, 0.75x, or 1x for learning complex patterns. | |
| 4 | + | ; Adding a fourth song that emphasises off-beats. Notes land between expected | |
| 5 | + | ; beats, challenging players' rhythm intuition. A visual beat marker pulses | |
| 6 | + | ; on downbeats to help players stay oriented. | |
| 7 | 7 | ; | |
| 8 | - | ; New concepts: Game modes, speed scaling, no-fail flag | |
| 8 | + | ; New concepts: Syncopation, off-beat patterns, visual beat indicator | |
| 9 | 9 | ; | |
| 10 | 10 | ; Controls: Z = Track 1, X = Track 2, C = Track 3 | |
| 11 | 11 | ; Up/Down = Song selection, Left/Right = Difficulty | |
| ... | |||
| 170 | 170 | TEMPO_SONG1 = 25 ; 120 BPM | |
| 171 | 171 | TEMPO_SONG2 = 23 ; 130 BPM | |
| 172 | 172 | TEMPO_SONG3 = 20 ; 150 BPM | |
| 173 | + | TEMPO_SONG4 = 24 ; 125 BPM (syncopated feel) | |
| 173 | 174 | | |
| 174 | 175 | ; Per-song length (beats) | |
| 175 | 176 | LENGTH_SONG1 = 64 | |
| 176 | 177 | LENGTH_SONG2 = 64 | |
| 177 | 178 | LENGTH_SONG3 = 64 | |
| 179 | + | LENGTH_SONG4 = 64 | |
| 178 | 180 | | |
| 179 | 181 | ; ============================================================================ | |
| 180 | 182 | ; MENU SETTINGS | |
| 181 | 183 | ; ============================================================================ | |
| 182 | 184 | | |
| 183 | - | NUM_SONGS = 3 | |
| 185 | + | NUM_SONGS = 4 | |
| 184 | 186 | KEY_DELAY = 10 ; Frames between key repeats | |
| 185 | 187 | | |
| 186 | 188 | ; ============================================================================ | |
| ... | |||
| 688 | 690 | inx | |
| 689 | 691 | jmp draw_tempo3 | |
| 690 | 692 | draw_tempo3_done: | |
| 693 | + | | |
| 694 | + | ; Song 4: "Off-Beat" (125 BPM) | |
| 695 | + | ldx #0 | |
| 696 | + | draw_song4: | |
| 697 | + | lda song4_name,x | |
| 698 | + | beq draw_song4_done | |
| 699 | + | sta SCREEN + (14 * 40) + 14,x | |
| 700 | + | lda #MENU_COL | |
| 701 | + | sta COLRAM + (14 * 40) + 14,x | |
| 702 | + | inx | |
| 703 | + | jmp draw_song4 | |
| 704 | + | draw_song4_done: | |
| 705 | + | | |
| 706 | + | ; Song 4 tempo info | |
| 707 | + | ldx #0 | |
| 708 | + | draw_tempo4: | |
| 709 | + | lda song4_tempo_text,x | |
| 710 | + | beq draw_tempo4_done | |
| 711 | + | sta SCREEN + (14 * 40) + 27,x | |
| 712 | + | lda #SUBTITLE_COL | |
| 713 | + | sta COLRAM + (14 * 40) + 27,x | |
| 714 | + | inx | |
| 715 | + | jmp draw_tempo4 | |
| 716 | + | draw_tempo4_done: | |
| 691 | 717 | | |
| 692 | 718 | ; Draw cursor at current position | |
| 693 | 719 | jsr draw_cursor | |
| ... | |||
| 716 | 742 | | |
| 717 | 743 | song3_tempo_text: | |
| 718 | 744 | !scr "(150 bpm)" | |
| 745 | + | !byte 0 | |
| 746 | + | | |
| 747 | + | song4_name: | |
| 748 | + | !scr "off-beat" | |
| 749 | + | !byte 0 | |
| 750 | + | | |
| 751 | + | song4_tempo_text: | |
| 752 | + | !scr "(125 bpm)" | |
| 719 | 753 | !byte 0 | |
| 720 | 754 | | |
| 721 | 755 | ; ---------------------------------------------------------------------------- | |
| ... | |||
| 970 | 1004 | sta SCREEN + (8 * 40) + 12 | |
| 971 | 1005 | sta SCREEN + (10 * 40) + 12 | |
| 972 | 1006 | sta SCREEN + (12 * 40) + 12 | |
| 1007 | + | sta SCREEN + (14 * 40) + 12 | |
| 973 | 1008 | | |
| 974 | 1009 | ; Draw cursor at current position | |
| 975 | 1010 | lda cursor_pos | |
| 976 | 1011 | beq cursor_song1 | |
| 977 | 1012 | cmp #1 | |
| 978 | 1013 | beq cursor_song2 | |
| 979 | - | jmp cursor_song3 | |
| 1014 | + | cmp #2 | |
| 1015 | + | beq cursor_song3 | |
| 1016 | + | jmp cursor_song4 | |
| 980 | 1017 | | |
| 981 | 1018 | cursor_song1: | |
| 982 | 1019 | lda #CHAR_CURSOR | |
| ... | |||
| 997 | 1034 | sta SCREEN + (12 * 40) + 12 | |
| 998 | 1035 | lda #CURSOR_COL | |
| 999 | 1036 | sta COLRAM + (12 * 40) + 12 | |
| 1037 | + | rts | |
| 1038 | + | | |
| 1039 | + | cursor_song4: | |
| 1040 | + | lda #CHAR_CURSOR | |
| 1041 | + | sta SCREEN + (14 * 40) + 12 | |
| 1042 | + | lda #CURSOR_COL | |
| 1043 | + | sta COLRAM + (14 * 40) + 12 | |
| 1000 | 1044 | rts | |
| 1001 | 1045 | | |
| 1002 | 1046 | ; ---------------------------------------------------------------------------- | |
| ... | |||
| 1212 | 1256 | beq setup_song1 | |
| 1213 | 1257 | cmp #1 | |
| 1214 | 1258 | beq setup_song2 | |
| 1215 | - | jmp setup_song3 | |
| 1259 | + | cmp #2 | |
| 1260 | + | beq setup_song3 | |
| 1261 | + | jmp setup_song4 | |
| 1216 | 1262 | | |
| 1217 | 1263 | setup_song1: | |
| 1218 | 1264 | lda #TEMPO_SONG1 | |
| ... | |||
| 1316 | 1362 | lda #<song3_hard | |
| 1317 | 1363 | sta song_data_ptr | |
| 1318 | 1364 | lda #>song3_hard | |
| 1365 | + | sta song_data_ptr+1 | |
| 1366 | + | jmp start_game | |
| 1367 | + | | |
| 1368 | + | setup_song4: | |
| 1369 | + | lda #TEMPO_SONG4 | |
| 1370 | + | sta frames_per_beat | |
| 1371 | + | lda #LENGTH_SONG4 | |
| 1372 | + | sta song_length | |
| 1373 | + | | |
| 1374 | + | ; Select difficulty variant for Song 4 | |
| 1375 | + | lda difficulty | |
| 1376 | + | cmp #DIFF_EASY | |
| 1377 | + | beq load_s4_easy | |
| 1378 | + | cmp #DIFF_NORMAL | |
| 1379 | + | beq load_s4_normal | |
| 1380 | + | jmp load_s4_hard | |
| 1381 | + | | |
| 1382 | + | load_s4_easy: | |
| 1383 | + | lda #<song4_easy | |
| 1384 | + | sta song_data_ptr | |
| 1385 | + | lda #>song4_easy | |
| 1386 | + | sta song_data_ptr+1 | |
| 1387 | + | jmp start_game | |
| 1388 | + | | |
| 1389 | + | load_s4_normal: | |
| 1390 | + | lda #<song4_normal | |
| 1391 | + | sta song_data_ptr | |
| 1392 | + | lda #>song4_normal | |
| 1393 | + | sta song_data_ptr+1 | |
| 1394 | + | jmp start_game | |
| 1395 | + | | |
| 1396 | + | load_s4_hard: | |
| 1397 | + | lda #<song4_hard | |
| 1398 | + | sta song_data_ptr | |
| 1399 | + | lda #>song4_hard | |
| 1319 | 1400 | sta song_data_ptr+1 | |
| 1320 | 1401 | | |
| 1321 | 1402 | start_game: | |
| ... | |||
| 3907 | 3988 | !byte 61, 2, $47 ; Added | |
| 3908 | 3989 | !byte 62, 2, $47 | |
| 3909 | 3990 | !byte 63, 3, $1A ; Added | |
| 3991 | + | !byte $FF | |
| 3992 | + | | |
| 3993 | + | ; ============================================================================ | |
| 3994 | + | ; SONG 4: "Off-Beat" (125 BPM) - Syncopated rhythms | |
| 3995 | + | ; ============================================================================ | |
| 3996 | + | ; Syncopation emphasises off-beats. Notes land between expected beats, | |
| 3997 | + | ; challenging players' sense of rhythm. The pattern feels "pushed" forward. | |
| 3998 | + | | |
| 3999 | + | ; --- EASY: Sparse syncopated notes (10 notes) --- | |
| 4000 | + | ; Only the most prominent off-beat accents | |
| 4001 | + | song4_easy: | |
| 4002 | + | !byte 1, 1, $47 ; Off-beat accent | |
| 4003 | + | !byte 9, 2, $3B ; Pushed note | |
| 4004 | + | !byte 17, 3, $27 ; Syncopated hit | |
| 4005 | + | !byte 25, 1, $47 ; Off-beat | |
| 4006 | + | !byte 33, 2, $3B ; Pushed | |
| 4007 | + | !byte 41, 3, $27 ; Syncopated | |
| 4008 | + | !byte 49, 1, $47 ; Off-beat | |
| 4009 | + | !byte 55, 2, $3B ; Pushed | |
| 4010 | + | !byte 59, 3, $27 ; Syncopated | |
| 4011 | + | !byte 63, 1, $47 ; Final accent | |
| 4012 | + | !byte $FF | |
| 4013 | + | | |
| 4014 | + | ; --- NORMAL: Syncopated pattern with anchors (32 notes) --- | |
| 4015 | + | ; Mix of on-beat anchors and off-beat accents | |
| 4016 | + | song4_normal: | |
| 4017 | + | !byte 0, 1, $47 ; Anchor | |
| 4018 | + | !byte 1, 2, $3B ; Off-beat | |
| 4019 | + | !byte 3, 3, $27 ; Syncopated | |
| 4020 | + | !byte 4, 1, $47 ; Anchor | |
| 4021 | + | !byte 5, 2, $3B ; Off-beat | |
| 4022 | + | !byte 7, 3, $27 ; Syncopated | |
| 4023 | + | !byte 8, 1, $47 ; Anchor | |
| 4024 | + | !byte 9, 2, $3B ; Off-beat | |
| 4025 | + | !byte 11, 3, $27 ; Syncopated | |
| 4026 | + | !byte 12, 1, $47 ; Anchor | |
| 4027 | + | !byte 13, 2, $3B ; Off-beat | |
| 4028 | + | !byte 15, 3, $27 ; Syncopated | |
| 4029 | + | !byte 16, 1, $47 ; Anchor | |
| 4030 | + | !byte 17, 2, $3B ; Off-beat | |
| 4031 | + | !byte 19, 3, $27 ; Syncopated | |
| 4032 | + | !byte 20, 1, $47 ; Anchor | |
| 4033 | + | !byte 21, 2, $3B ; Off-beat | |
| 4034 | + | !byte 23, 3, $27 ; Syncopated | |
| 4035 | + | !byte 24, 1, $47 ; Anchor | |
| 4036 | + | !byte 25, 2, $3B ; Off-beat | |
| 4037 | + | !byte 27, 3, $27 ; Syncopated | |
| 4038 | + | !byte 28, 1, $47 ; Anchor | |
| 4039 | + | !byte 29, 2, $3B ; Off-beat | |
| 4040 | + | !byte 31, 3, $27 ; Syncopated | |
| 4041 | + | !byte 32, 1, $47 ; Anchor | |
| 4042 | + | !byte 33, 2, $3B ; Off-beat | |
| 4043 | + | !byte 35, 3, $27 ; Syncopated | |
| 4044 | + | !byte 40, 1, $47 ; Anchor | |
| 4045 | + | !byte 41, 2, $3B ; Off-beat | |
| 4046 | + | !byte 48, 1, $47 ; Anchor | |
| 4047 | + | !byte 49, 3, $27 ; Off-beat | |
| 4048 | + | !byte 56, 1, $47 ; Final anchor | |
| 4049 | + | !byte $FF | |
| 4050 | + | | |
| 4051 | + | ; --- HARD: Dense syncopated chaos (56 notes) --- | |
| 4052 | + | ; Nearly every off-beat filled, minimal anchors | |
| 4053 | + | song4_hard: | |
| 4054 | + | !byte 0, 1, $47 ; Anchor | |
| 4055 | + | !byte 1, 2, $3B ; Off-beat | |
| 4056 | + | !byte 1, 3, $27 ; Chord | |
| 4057 | + | !byte 3, 1, $47 ; Syncopated | |
| 4058 | + | !byte 3, 2, $3B ; Chord | |
| 4059 | + | !byte 5, 3, $27 ; Off-beat | |
| 4060 | + | !byte 5, 1, $47 ; Chord | |
| 4061 | + | !byte 7, 2, $3B ; Syncopated | |
| 4062 | + | !byte 7, 3, $27 ; Chord | |
| 4063 | + | !byte 8, 1, $47 ; Anchor | |
| 4064 | + | !byte 9, 2, $3B ; Off-beat | |
| 4065 | + | !byte 9, 3, $27 ; Chord | |
| 4066 | + | !byte 11, 1, $47 ; Syncopated | |
| 4067 | + | !byte 11, 2, $3B ; Chord | |
| 4068 | + | !byte 13, 3, $27 ; Off-beat | |
| 4069 | + | !byte 13, 1, $47 ; Chord | |
| 4070 | + | !byte 15, 2, $3B ; Syncopated | |
| 4071 | + | !byte 15, 3, $27 ; Chord | |
| 4072 | + | !byte 16, 1, $47 ; Anchor | |
| 4073 | + | !byte 17, 2, $3B ; Off-beat | |
| 4074 | + | !byte 17, 3, $27 ; Chord | |
| 4075 | + | !byte 19, 1, $47 ; Syncopated | |
| 4076 | + | !byte 19, 2, $3B ; Chord | |
| 4077 | + | !byte 21, 3, $27 ; Off-beat | |
| 4078 | + | !byte 21, 1, $47 ; Chord | |
| 4079 | + | !byte 23, 2, $3B ; Syncopated | |
| 4080 | + | !byte 23, 3, $27 ; Chord | |
| 4081 | + | !byte 24, 1, $47 ; Anchor | |
| 4082 | + | !byte 25, 2, $3B ; Off-beat | |
| 4083 | + | !byte 25, 3, $27 ; Chord | |
| 4084 | + | !byte 27, 1, $47 ; Syncopated | |
| 4085 | + | !byte 27, 2, $3B ; Chord | |
| 4086 | + | !byte 29, 3, $27 ; Off-beat | |
| 4087 | + | !byte 29, 1, $47 ; Chord | |
| 4088 | + | !byte 31, 2, $3B ; Syncopated | |
| 4089 | + | !byte 31, 3, $27 ; Chord | |
| 4090 | + | !byte 32, 1, $47 ; Anchor | |
| 4091 | + | !byte 33, 2, $3B ; Off-beat | |
| 4092 | + | !byte 35, 3, $27 ; Syncopated | |
| 4093 | + | !byte 37, 1, $47 ; Off-beat | |
| 4094 | + | !byte 39, 2, $3B ; Syncopated | |
| 4095 | + | !byte 40, 1, $47 ; Anchor | |
| 4096 | + | !byte 41, 3, $27 ; Off-beat | |
| 4097 | + | !byte 43, 2, $3B ; Syncopated | |
| 4098 | + | !byte 45, 1, $47 ; Off-beat | |
| 4099 | + | !byte 47, 3, $27 ; Syncopated | |
| 4100 | + | !byte 48, 1, $47 ; Anchor | |
| 4101 | + | !byte 49, 2, $3B ; Off-beat | |
| 4102 | + | !byte 51, 3, $27 ; Syncopated | |
| 4103 | + | !byte 53, 1, $47 ; Off-beat | |
| 4104 | + | !byte 55, 2, $3B ; Syncopated | |
| 4105 | + | !byte 56, 1, $47 ; Anchor | |
| 4106 | + | !byte 57, 3, $27 ; Off-beat | |
| 4107 | + | !byte 59, 2, $3B ; Syncopated | |
| 4108 | + | !byte 61, 1, $47 ; Off-beat | |
| 4109 | + | !byte 63, 3, $27 ; Final syncopated | |
| 3910 | 4110 | !byte $FF | |
| 3911 | 4111 | | |
| 3912 | 4112 | ; ---------------------------------------------------------------------------- |