1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
//! Decoder for converting FNF .json to `RoxChart`.
use crate::codec::Decoder;
use crate::error::RoxResult;
use crate::model::{Metadata, Note, RoxChart, TimingPoint};
use super::parser;
use super::types::{FnfChart, FnfSide};
/// Decoder for Friday Night Funkin' charts.
pub struct FnfDecoder;
impl FnfDecoder {
/// Decode with a specific side selection.
///
/// # Errors
///
/// Returns an error if parsing fails.
pub fn decode_with_side(data: &[u8], side: FnfSide) -> RoxResult<RoxChart> {
let fnf = parser::parse(data)?;
Ok(Self::from_fnf(&fnf, side))
}
/// Convert an `FnfChart` to `RoxChart` with the specified side.
#[must_use]
pub fn from_fnf(fnf: &FnfChart, side: FnfSide) -> RoxChart {
let key_count = match side {
FnfSide::Player | FnfSide::Opponent => 4,
FnfSide::Both => 8,
};
let mut chart = RoxChart::new(key_count);
// Map metadata
chart.metadata = Metadata {
key_count,
title: fnf.song.song.clone().into(),
artist: "Unknown".into(),
creator: fnf.song.player2.clone().into(),
difficulty_name: "Normal".into(),
audio_file: "Inst.ogg".into(),
// FNF usually has a separate Voices track, but we'll map Inst as main audio
background_file: None,
preview_time_us: 0,
source: Some("Friday Night Funkin'".into()),
tags: vec!["fnf".into()],
is_coop: side == FnfSide::Both, // true for 8K coop mode
..Default::default()
};
// Track current BPM for timing points
let mut current_bpm = fnf.song.bpm;
let mut added_initial_bpm = false;
// Process each section
for section in &fnf.song.notes {
// Handle BPM changes
if section.change_bpm && section.bpm > 0.0 {
// Find the first note time in this section for the timing point
if let Some(first_note) = section.section_notes.first() {
#[allow(clippy::cast_possible_truncation)]
let time_us = (first_note.time_ms() * 1000.0) as i64;
chart
.timing_points
.push(TimingPoint::bpm(time_us, section.bpm));
current_bpm = section.bpm;
}
} else if !added_initial_bpm {
// Add initial BPM at time 0
chart.timing_points.push(TimingPoint::bpm(0, current_bpm));
added_initial_bpm = true;
}
// Process notes in this section
for fnf_note in §ion.section_notes {
let raw_lane = fnf_note.lane();
// Determine if this note belongs to player or opponent
// In FNF: mustHitSection determines which side is which
// mustHitSection=true: lanes 0-3 = player, 4-7 = opponent
// mustHitSection=false: lanes 0-3 = opponent, 4-7 = player
let (is_player_note, base_lane) = if raw_lane < 4 {
(section.must_hit_section, raw_lane)
} else {
(!section.must_hit_section, raw_lane - 4)
};
// Filter based on requested side
let column = match side {
FnfSide::Player => {
if is_player_note {
Some(base_lane)
} else {
None
}
}
FnfSide::Opponent => {
if is_player_note {
None
} else {
Some(base_lane)
}
}
FnfSide::Both => {
// Opponent on left (0-3), player on right (4-7)
if is_player_note {
Some(base_lane + 4)
} else {
Some(base_lane)
}
}
};
if let Some(col) = column {
#[allow(clippy::cast_possible_truncation)]
let time_us = (fnf_note.time_ms() * 1000.0) as i64;
let note = if fnf_note.is_hold() {
#[allow(clippy::cast_possible_truncation)]
let duration_us = (fnf_note.duration_ms() * 1000.0) as i64;
Note::hold(time_us, duration_us, col)
} else {
Note::tap(time_us, col)
};
chart.notes.push(note);
}
}
}
// Add initial BPM if no sections had notes
if !added_initial_bpm {
chart.timing_points.push(TimingPoint::bpm(0, fnf.song.bpm));
}
// Sort notes and timing points by time
chart.notes.sort_by_key(|n| n.time_us);
chart.timing_points.sort_by_key(|tp| tp.time_us);
chart
}
}
impl Decoder for FnfDecoder {
/// Decode FNF chart, extracting player notes only (4K).
fn decode(data: &[u8]) -> RoxResult<RoxChart> {
Self::decode_with_side(data, FnfSide::Player)
}
}
#[cfg(test)]
mod tests {
use super::*;
use crate::codec::Decoder;
#[test]
#[ignore = "FNF is currently WIP/Unstable"]
fn test_decode_asset_fnf_player() {
// assets/fnf/test-song.json
let data = crate::test_utils::get_test_asset("fnf/test-song.json");
let chart =
<FnfDecoder as Decoder>::decode(&data).expect("Failed to decode test-song.json");
// Basic validation
assert_eq!(chart.key_count(), 4); // Player side is 4K
assert!(!chart.notes.is_empty());
assert!(!chart.timing_points.is_empty());
}
#[test]
#[ignore = "FNF is currently WIP/Unstable"]
fn test_decode_asset_fnf_both() {
let data = crate::test_utils::get_test_asset("fnf/test-song.json");
let chart = FnfDecoder::decode_with_side(&data, FnfSide::Both)
.expect("Failed to decode both sides");
assert_eq!(chart.key_count(), 8); // Both sides is 8K
assert!(chart.metadata.is_coop);
}
}