diff --git a/frontends/sdl/src/main.rs b/frontends/sdl/src/main.rs
index 4dcb15e35a8bf98e919c8381840c1239cc30e998..40972d9bb3fac616891190e2cdfa6bc0ce268300 100644
--- a/frontends/sdl/src/main.rs
+++ b/frontends/sdl/src/main.rs
@@ -24,7 +24,7 @@ static TITLE: &str = "Boytacean";
/// Base audio volume to be used as the basis of the
/// amplification level of the volume
-static VOLUME: f32 = 100.0;
+static VOLUME: f32 = 40.0;
pub struct Benchmark {
count: usize,
diff --git a/src/apu.rs b/src/apu.rs
index e9f343bd11d99f0380b791fb0d9787ef2e58f952..5754345c1604ca3b08fd3f8654de8afece9ca597 100644
--- a/src/apu.rs
+++ b/src/apu.rs
@@ -17,6 +17,8 @@ pub enum Channel {
pub struct Apu {
ch1_timer: u16,
ch1_sequence: u8,
+ ch1_envelope_sequence: u8,
+ ch1_envelope_enabled: bool,
ch1_sweep_sequence: u8,
ch1_output: u8,
ch1_sweep_slope: u8,
@@ -28,11 +30,13 @@ pub struct Apu {
ch1_direction: u8,
ch1_volume: u8,
ch1_wave_length: u16,
- ch1_sound_length: bool,
+ ch1_length_stop: bool,
ch1_enabled: bool,
ch2_timer: u16,
ch2_sequence: u8,
+ ch2_envelope_sequence: u8,
+ ch2_envelope_enabled: bool,
ch2_output: u8,
ch2_length_timer: u8,
ch2_wave_duty: u8,
@@ -40,10 +44,9 @@ pub struct Apu {
ch2_direction: u8,
ch2_volume: u8,
ch2_wave_length: u16,
- ch2_sound_length: bool,
+ ch2_length_stop: bool,
ch2_enabled: bool,
- // @TODO start using this once we're ready for CH3
ch3_timer: u16,
ch3_position: u8,
ch3_output: u8,
@@ -51,7 +54,7 @@ pub struct Apu {
ch3_length_timer: u8,
ch3_output_level: u8,
ch3_wave_length: u16,
- ch3_sound_length: bool,
+ ch3_length_stop: bool,
ch3_enabled: bool,
wave_ram: [u8; 16],
@@ -68,6 +71,8 @@ impl Apu {
Self {
ch1_timer: 0,
ch1_sequence: 0,
+ ch1_envelope_sequence: 0,
+ ch1_envelope_enabled: false,
ch1_sweep_sequence: 0,
ch1_output: 0,
ch1_sweep_slope: 0x0,
@@ -79,11 +84,13 @@ impl Apu {
ch1_direction: 0x0,
ch1_volume: 0x0,
ch1_wave_length: 0x0,
- ch1_sound_length: false,
+ ch1_length_stop: false,
ch1_enabled: false,
ch2_timer: 0,
ch2_sequence: 0,
+ ch2_envelope_sequence: 0,
+ ch2_envelope_enabled: false,
ch2_output: 0,
ch2_length_timer: 0x0,
ch2_wave_duty: 0x0,
@@ -91,10 +98,9 @@ impl Apu {
ch2_direction: 0x0,
ch2_volume: 0x0,
ch2_wave_length: 0x0,
- ch2_sound_length: false,
+ ch2_length_stop: false,
ch2_enabled: false,
- // @TODO start using this once we're ready for CH3
ch3_timer: 0,
ch3_position: 0,
ch3_output: 0,
@@ -102,7 +108,7 @@ impl Apu {
ch3_length_timer: 0x0,
ch3_output_level: 0x0,
ch3_wave_length: 0x0,
- ch3_sound_length: false,
+ ch3_length_stop: false,
ch3_enabled: false,
wave_ram: [0u8; 16],
@@ -139,6 +145,7 @@ impl Apu {
self.ch1_sweep_slope = value & 0x07;
self.ch1_sweep_increase = value & 0x08 == 0x00;
self.ch1_sweep_pace = (value & 0x70) >> 4;
+ self.ch1_sweep_sequence = 0;
}
// 0xFF11 — NR11: Channel 1 length timer & duty cycle
0xff11 => {
@@ -150,6 +157,8 @@ impl Apu {
self.ch1_pace = value & 0x07;
self.ch1_direction = (value & 0x08) >> 3;
self.ch1_volume = (value & 0xf0) >> 4;
+ self.ch1_envelope_enabled = self.ch1_pace > 0;
+ self.ch1_envelope_sequence = 0;
}
// 0xFF13 — NR13: Channel 1 wavelength low
0xff13 => {
@@ -159,7 +168,7 @@ impl Apu {
0xff14 => {
self.ch1_wave_length =
(self.ch1_wave_length & 0x00ff) | (((value & 0x07) as u16) << 8);
- self.ch1_sound_length |= value & 0x40 == 0x40;
+ self.ch1_length_stop |= value & 0x40 == 0x40;
self.ch1_enabled |= value & 0x80 == 0x80;
}
@@ -182,7 +191,7 @@ impl Apu {
0xff19 => {
self.ch2_wave_length =
(self.ch2_wave_length & 0x00ff) | (((value & 0x07) as u16) << 8);
- self.ch2_sound_length |= value & 0x40 == 0x40;
+ self.ch2_length_stop |= value & 0x40 == 0x40;
self.ch2_enabled |= value & 0x80 == 0x80;
}
@@ -206,7 +215,7 @@ impl Apu {
0xff1e => {
self.ch3_wave_length =
(self.ch3_wave_length & 0x00ff) | (((value & 0x07) as u16) << 8);
- self.ch3_sound_length |= value & 0x40 == 0x40;
+ self.ch3_length_stop |= value & 0x40 == 0x40;
self.ch3_enabled |= value & 0x80 == 0x80;
}
@@ -239,7 +248,8 @@ impl Apu {
fn tick(&mut self) {
self.sequencer += 1;
if self.sequencer >= 8192 {
- // each of these steps runs at 518/8 Hz = 64Hz
+ // each of these steps runs at 512/8 Hz = 64Hz,
+ // meaning a complete loop runs at 512 Hz
match self.sequencer_step {
0 => {
self.tick_length_all();
@@ -259,9 +269,7 @@ impl Apu {
self.tick_length_all();
}
7 => {
- //channels[0]->envelope_clock();
- //channels[1]->envelope_clock();
- //channels[3]->envelope_clock();
+ self.tick_envelope_all();
}
_ => (),
}
@@ -291,23 +299,26 @@ impl Apu {
fn tick_length(&mut self, channel: Channel) {
match channel {
Channel::Ch1 => {
+ if !self.ch1_enabled {
+ return;
+ }
self.ch1_length_timer = self.ch1_length_timer.saturating_add(1);
if self.ch1_length_timer >= 64 {
- self.ch1_enabled = false;
+ self.ch1_enabled = !self.ch1_length_stop;
self.ch1_length_timer = 0;
}
}
Channel::Ch2 => {
self.ch2_length_timer = self.ch2_length_timer.saturating_add(1);
if self.ch2_length_timer >= 64 {
- self.ch2_enabled = false;
+ self.ch2_enabled = !self.ch2_length_stop;
self.ch2_length_timer = 0;
}
}
Channel::Ch3 => {
self.ch3_length_timer = self.ch3_length_timer.saturating_add(1);
if self.ch3_length_timer >= 64 {
- self.ch3_enabled = false;
+ self.ch3_enabled = !self.ch3_length_stop;
self.ch3_length_timer = 0;
}
}
@@ -315,6 +326,51 @@ impl Apu {
}
}
+ fn tick_envelope_all(&mut self) {
+ self.tick_envelope(Channel::Ch1);
+ }
+
+ fn tick_envelope(&mut self, channel: Channel) {
+ match channel {
+ Channel::Ch1 => {
+ if !self.ch1_enabled || !self.ch1_envelope_enabled {
+ return;
+ }
+ self.ch1_envelope_sequence += 1;
+ if self.ch1_envelope_sequence >= self.ch1_pace {
+ if self.ch1_direction == 0x01 {
+ self.ch1_volume = self.ch1_volume.saturating_add(1);
+ } else {
+ self.ch1_volume = self.ch1_volume.saturating_sub(1);
+ }
+ if self.ch1_volume == 0 || self.ch1_volume == 15 {
+ self.ch1_envelope_enabled = false;
+ }
+ self.ch1_envelope_sequence = 0;
+ }
+ }
+ Channel::Ch2 => {
+ if !self.ch2_enabled || !self.ch2_envelope_enabled {
+ return;
+ }
+ self.ch2_envelope_sequence += 1;
+ if self.ch2_envelope_sequence >= self.ch2_pace {
+ if self.ch2_direction == 0x01 {
+ self.ch2_volume = self.ch2_volume.saturating_add(1);
+ } else {
+ self.ch2_volume = self.ch2_volume.saturating_sub(1);
+ }
+ if self.ch2_volume == 0 || self.ch2_volume == 15 {
+ self.ch2_envelope_enabled = false;
+ }
+ self.ch2_envelope_sequence = 0;
+ }
+ }
+ Channel::Ch3 => (),
+ Channel::Ch4 => (),
+ }
+ }
+
fn tick_ch1_sweep(&mut self) {
if self.ch1_sweep_pace == 0x0 {
return;
@@ -403,7 +459,6 @@ impl Apu {
} else {
output = 0;
}
- //println!("{} {}", self.ch3_output, self.ch3_output_level);
self.ch3_output = output;
} else {
self.ch3_output = 0;