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fix(snd): increase accuracy of when to sample from APU

This commit is contained in:
Rekai Nyangadzayi Musuka 2021-07-10 22:35:54 -05:00
parent 7ab6e120f9
commit 3dbf026d33
1 changed files with 6 additions and 6 deletions
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12
src/sound.rs
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@ -6,7 +6,8 @@ use crate::emu::SM83_CLOCK_SPEED;
use crate::Cycle;
const WAVE_PATTERN_RAM_LEN: usize = 0x10;
const SAMPLE_RATE: u32 = 4800; // Hz
const SAMPLE_RATE: u32 = 48000; // Hz
const SAMPLE_INCREMENT: u64 = SAMPLE_RATE as u64;
const SAMPLE_RATE_IN_CYCLES: Cycle = Cycle::new((SM83_CLOCK_SPEED / SAMPLE_RATE as u64) as u32);
#[derive(Debug, Clone, Default)]
@ -26,13 +27,13 @@ pub(crate) struct Sound {
div_prev: Option<u8>,
sender: Option<SampleSender>,
cycle: Cycle,
sample_counter: u64,
}
impl Sound {
pub(crate) fn clock(&mut self, div: u16) {
use FrameSequencerState::*;
self.cycle += 1;
self.sample_counter += SAMPLE_INCREMENT;
// the 5th bit of the high byte
let bit_5 = (div >> 13 & 0x01) as u8;
@ -64,10 +65,9 @@ impl Sound {
self.div_prev = Some(bit_5);
// TODO: Should the FrameSequencer be run first?
if self.cycle > SAMPLE_RATE_IN_CYCLES {
if self.sample_counter >= SM83_CLOCK_SPEED {
// Sample the APU
self.cycle %= SAMPLE_RATE_IN_CYCLES;
self.sample_counter %= SM83_CLOCK_SPEED;
let ch1_amplitude = self.ch1.amplitude();
let ch1_left = self.ctrl.output.ch1_left() as u8 as f32 * ch1_amplitude;