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-rw-r--r--src/audio.rs91
1 files changed, 33 insertions, 58 deletions
diff --git a/src/audio.rs b/src/audio.rs
index cd8eeb2..b8f6aa9 100644
--- a/src/audio.rs
+++ b/src/audio.rs
@@ -29,50 +29,6 @@ const SQUARE_WAVE_PATTERN_DUTY_3: [u8; 32] = [
0, 1, 0, 1, 0, 2,
];
-/*
- * Sometimes, you have to abandon the idea of doing things the right way and just do the thing.
- *
- * The Gameboy noise wave generation function is stateful and the sample averaging feature (a
- * low pass filter to filter out some weird noises created by the "too squared" nature of our
- * sound wave) needs a pure function (and fast). It's too hard so I just computed the result
- * of the noise function and put it here. It's O(1) :3
- */
-
-const NOISE_WAVE: [u16; 1023] = [
- 1, 1, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 1, 1, 0, 1, 0, 0, 0, 0, 1, 1, 0, 1, 0, 1, 1,
- 1, 0, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 0, 1, 1, 0, 0, 1, 1, 0, 0, 1, 0, 1, 0, 1, 1, 0, 0, 1, 0,
- 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 0, 0, 0, 0, 1, 1, 1, 0, 0, 0, 1, 1, 0, 1, 0, 1, 1, 0, 0, 1, 1, 0,
- 0, 1, 1, 0, 0, 0, 0, 1, 0, 1, 0, 0, 0, 1, 1, 1, 0, 1, 1, 1, 1, 0, 0, 1, 1, 0, 0, 1, 0, 0, 1, 0,
- 0, 1, 1, 0, 1, 0, 0, 1, 1, 1, 0, 0, 0, 1, 0, 0, 1, 1, 0, 1, 0, 0, 1, 0, 0, 0, 1, 0, 1, 0, 1, 1,
- 1, 1, 0, 0, 1, 1, 1, 0, 1, 1, 1, 1, 1, 1, 0, 1, 0, 1, 1, 1, 0, 1, 1, 1, 1, 0, 1, 1, 1, 1, 0, 0,
- 0, 0, 1, 1, 0, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 1, 0, 1, 1, 0, 1, 1, 1, 0, 0, 1, 0, 1,
- 0, 0, 0, 0, 0, 1, 0, 0, 1, 0, 1, 0, 0, 0, 1, 0, 0, 1, 0, 1, 0, 0, 1, 1, 0, 1, 0, 1, 0, 1, 1, 0,
- 0, 1, 1, 1, 1, 1, 0, 0, 1, 0, 0, 1, 0, 0, 1, 1, 1, 0, 0, 1, 1, 1, 1, 0, 0, 1, 0, 1, 1, 1, 1, 0,
- 1, 1, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 1, 0, 1, 1, 1, 1, 0, 1, 0, 0, 1, 1, 0, 0, 0, 0,
- 0, 0, 0, 1, 0, 0, 1, 1, 0, 1, 1, 1, 0, 1, 0, 0, 1, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1, 1, 0, 1,
- 1, 0, 1, 1, 0, 1, 0, 1, 0, 0, 0, 1, 0, 1, 1, 1, 0, 1, 1, 1, 0, 1, 1, 1, 1, 1, 0, 0, 1, 0, 1, 0,
- 0, 0, 1, 1, 1, 1, 1, 1, 1, 0, 0, 1, 1, 0, 0, 1, 0, 1, 0, 0, 1, 0, 0, 0, 1, 1, 0, 1, 0, 0, 1, 1,
- 1, 1, 1, 0, 0, 0, 1, 1, 1, 0, 0, 1, 0, 0, 1, 0, 1, 1, 0, 1, 0, 1, 0, 1, 1, 0, 1, 1, 0, 0, 1, 0,
- 0, 1, 0, 1, 1, 0, 1, 0, 0, 0, 1, 0, 0, 1, 0, 0, 0, 0, 1, 1, 0, 1, 0, 1, 1, 0, 1, 1, 0, 1, 0, 1,
- 1, 1, 0, 1, 0, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 1, 0, 0, 1, 1, 1, 0, 0, 1, 1, 1, 0, 0, 0, 0, 1, 1,
- 0, 0, 1, 0, 0, 0, 1, 0, 1, 0, 0, 1, 0, 1, 0, 0, 1, 1, 1, 1, 1, 0, 1, 0, 0, 0, 0, 1, 1, 0, 1, 1,
- 1, 1, 0, 1, 0, 0, 1, 0, 0, 0, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 0, 0, 0, 0, 1, 0, 0, 0, 1, 1,
- 0, 1, 0, 0, 1, 1, 0, 1, 0, 1, 1, 0, 0, 1, 1, 1, 0, 0, 0, 1, 0, 1, 0, 0, 1, 1, 0, 0, 0, 0, 1, 0,
- 0, 0, 0, 0, 0, 1, 0, 1, 0, 0, 1, 1, 1, 1, 1, 0, 0, 0, 1, 1, 1, 0, 0, 0, 1, 0, 0, 1, 0, 0, 0, 1,
- 0, 0, 1, 1, 0, 0, 0, 1, 1, 1, 0, 1, 0, 1, 1, 0, 1, 1, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0,
- 1, 1, 0, 0, 0, 1, 0, 1, 0, 1, 0, 1, 1, 0, 0, 0, 0, 1, 0, 0, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 1, 0,
- 1, 0, 0, 1, 1, 1, 0, 1, 0, 1, 1, 0, 0, 1, 0, 0, 1, 1, 0, 0, 0, 0, 0, 1, 1, 1, 1, 0, 1, 0, 1, 0,
- 0, 1, 1, 0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 1, 1, 0, 1,
- 1, 0, 1, 0, 0, 0, 0, 1, 0, 1, 0, 0, 0, 1, 1, 0, 1, 1, 1, 0, 0, 0, 0, 1, 1, 0, 1, 0, 0, 0, 1, 1,
- 0, 1, 1, 1, 1, 1, 0, 1, 0, 1, 0, 0, 0, 1, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 1, 0, 1, 1, 1, 1, 0, 1,
- 1, 1, 1, 1, 0, 1, 0, 1, 0, 0, 1, 1, 1, 0, 1, 0, 0, 0, 1, 1, 1, 0, 1, 0, 1, 0, 1, 1, 1, 1, 0, 1,
- 1, 0, 0, 1, 1, 1, 0, 0, 0, 0, 1, 0, 0, 1, 1, 1, 1, 1, 0, 0, 0, 1, 0, 0, 0, 1, 1, 0, 0, 0, 0, 0,
- 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1, 1, 0, 1, 1, 0, 0, 1, 0, 0, 1, 1, 1, 0, 1, 0,
- 0, 1, 0, 1, 0, 0, 0, 1, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 1, 1, 0, 1, 0, 1, 1, 1, 0, 0,
- 1, 0, 0, 0, 1, 1, 0, 0, 1, 0, 1, 0, 0, 1, 0, 0, 0, 0, 1, 0, 1, 0, 0, 0, 1, 0, 1, 0, 0, 0, 0, 1,
- 0, 1, 1, 0, 0, 0, 0, 0, 0, 1, 1, 1, 0, 1, 0, 0, 1, 1, 0, 0, 1, 0, 0, 1, 0, 1, 1, 1, 0, 0, 1,
-];
-
const SQUARE_WAVE_PATTERNS: [[u8; 32]; 4] = [
SQUARE_WAVE_PATTERN_DUTY_0,
SQUARE_WAVE_PATTERN_DUTY_1,
@@ -233,6 +189,12 @@ pub struct NoiseWave {
clock_shift: u8,
lsfr_width: u8,
clock_divider: u8,
+
+ rng: u16,
+ last_i: usize,
+
+ left_volume: u8,
+ right_volume: u8,
}
impl NoiseWave {
@@ -246,6 +208,8 @@ impl NoiseWave {
clock_shift: u8,
lsfr_width: u8,
clock_divider: u8,
+ left_volume: u8,
+ right_volume: u8,
) -> NoiseWave {
NoiseWave {
num_sample,
@@ -257,6 +221,10 @@ impl NoiseWave {
clock_shift,
lsfr_width,
clock_divider,
+ rng: 0x42,
+ last_i: 0,
+ left_volume,
+ right_volume,
}
}
}
@@ -296,26 +264,31 @@ impl io::Wave for NoiseWave {
envelope
};
- let mut avg = 0.;
+ let ns = ((262144. / ((clock_divider) * (2 << self.clock_shift) as f32)) / 32768.)
+ * self.num_sample as f32;
- for n in 0..SAMPLE_AVERAGING {
- if self.num_sample as i32 + n as i32 - SAMPLE_AVERAGING as i32 >= 0 {
- let ns = ((262144. / ((clock_divider) * (2 << self.clock_shift) as f32)) / 32768.)
- * (self.num_sample + n - (SAMPLE_AVERAGING / 2)) as f32;
-
- let i = (ns as f32 * (32768 as f32 / SAMPLE_RATE as f32)) as usize;
+ let i = (ns as f32 * (32768 as f32 / SAMPLE_RATE as f32)) as usize;
- let up = if self.lsfr_width == 1 {
- NOISE_WAVE[i % 63]
- } else {
- NOISE_WAVE[i % 1023]
- };
+ let up = self.rng & 1;
+ if i != self.last_i {
+ self.last_i = i;
- avg += up as f32 * 2. - 1.;
+ self.rng >>= 1;
+ if self.lsfr_width == 1 {
+ self.rng |= ((self.rng & 1) ^ ((self.rng >> 1) & 1)) << 7;
+ } else {
+ self.rng |= ((self.rng & 1) ^ ((self.rng >> 1) & 1)) << 15;
}
}
- Some((avg / SAMPLE_AVERAGING as f32) * envelope_boundaries / 32.)
+ let mut res = up as f32 * 2. - 1.;
+ if left {
+ res = (self.left_volume as f32 / 8.) * res;
+ } else {
+ res = (self.right_volume as f32 / 8.) * res;
+ }
+
+ Some(res * envelope_boundaries / 64.)
}
}
@@ -595,6 +568,8 @@ impl AudioNoiseChannel {
self.clock_shift,
self.lsfr_width,
self.clock_divider,
+ if self.left { self.left_volume + 1 } else { 0 },
+ if self.right { self.right_volume + 1 } else { 0 },
));
} else {
*wave = None;
generated by cgit v1.2.3-70-g09d2 (git 2.46.0) at 2025-09-06 20:38:42 +0000