chore: redo apu sampling
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parent
a2d2a84850
commit
e70fe73899
216
src/apu.zig
216
src/apu.zig
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@ -53,7 +53,7 @@ pub const Apu = struct {
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.bias = .{ .raw = 0x0200 },
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.sampling_cycle = 0b00,
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.stream = SDL.SDL_NewAudioStream(SDL.AUDIO_F32, 2, 1 << 15, SDL.AUDIO_F32, 2, host_sample_rate) orelse unreachable,
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.stream = SDL.SDL_NewAudioStream(SDL.AUDIO_U16, 2, 1 << 15, SDL.AUDIO_U16, 2, host_sample_rate) orelse unreachable,
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.sched = sched,
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.capacitor = 0,
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@ -133,64 +133,60 @@ pub const Apu = struct {
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}
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pub fn sampleAudio(self: *Self, late: u64) void {
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// zig fmt: off
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const any_ch_enabled = self.ch1.enabled
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or self.ch2.enabled
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or self.ch3.enabled
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or self.ch4.enabled;
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// zig fmt: on
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var left: i16 = 0;
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var right: i16 = 0;
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// SOUNDCNT_L Channel Enable flags
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const ch_left: u4 = self.psg_cnt.ch_left.read();
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const ch_right: u4 = self.psg_cnt.ch_right.read();
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// FIXME: Obscure behaviour?
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// Apply NR50 Volume Modifications
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const left_master_vol = (@intToFloat(f32, self.psg_cnt.left_vol.read()) + 1.0) / 7.0;
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const right_master_vol = (@intToFloat(f32, self.psg_cnt.right_vol.read()) + 1.0) / 7.0;
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// Apply SOUNDCNT_H Volume Modifications
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const gba_vol: f32 = switch (self.dma_cnt.ch_vol.read()) {
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0b00 => 0.25,
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0b01 => 0.5,
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0b10 => 0.75,
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0b11 => 0.0,
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// Determine SOUNDCNT_H volume modifications
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const gba_vol: u4 = switch (self.dma_cnt.ch_vol.read()) {
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0b00 => 2,
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0b01 => 1,
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else => 0,
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};
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// Sample Channel 1
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const ch1_sample = self.highPass(self.ch1.amplitude(), any_ch_enabled);
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const ch1_left = if (ch_left & 1 == 1) ch1_sample else 0;
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const ch1_right = if (ch_right & 1 == 1) ch1_sample else 0;
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// Add all PSG channels together
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left += if (ch_left & 1 == 1) self.ch1.amplitude() else 0;
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left += if (ch_left >> 1 & 1 == 1) self.ch2.amplitude() else 0;
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left += if (ch_left >> 2 & 1 == 1) self.ch3.amplitude() else 0;
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left += if (ch_left >> 3 == 1) self.ch4.amplitude() else 0;
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// Sample Channel 2
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const ch2_sample = self.highPass(self.ch2.amplitude(), any_ch_enabled);
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const ch2_left = if (ch_left >> 1 & 1 == 1) ch2_sample else 0;
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const ch2_right = if (ch_right >> 1 & 1 == 1) ch2_sample else 0;
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right += if (ch_right & 1 == 1) self.ch1.amplitude() else 0;
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right += if (ch_right >> 1 & 1 == 1) self.ch2.amplitude() else 0;
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right += if (ch_right >> 2 & 1 == 1) self.ch3.amplitude() else 0;
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right += if (ch_right >> 3 == 1) self.ch4.amplitude() else 0;
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// Sample Channel 3
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const ch3_sample = self.highPass(self.ch3.amplitude(), any_ch_enabled);
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const ch3_left = if (ch_left >> 2 & 1 == 1) ch3_sample else 0;
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const ch3_right = if (ch_right >> 2 & 1 == 1) ch3_sample else 0;
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// Multiply by master channel volume
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left *= 1 + @as(i16, self.psg_cnt.left_vol.read());
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right *= 1 + @as(i16, self.psg_cnt.right_vol.read());
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// Sample Channel 4
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const ch4_sample = self.highPass(self.ch4.amplitude(), any_ch_enabled);
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const ch4_left = if (ch_left >> 3 == 1) ch4_sample else 0;
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const ch4_right = if (ch_right >> 3 == 1) ch4_sample else 0;
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// Apply GBA volume modifications to PSG Channels
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left >>= gba_vol;
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right >>= gba_vol;
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const psg_left = (ch1_left + ch2_left + ch3_left + ch4_left) * left_master_vol * gba_vol;
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const psg_right = (ch1_right + ch2_right + ch3_right + ch4_right) * right_master_vol * gba_vol;
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const chA_sample = self.chA.amplitude() << if (self.dma_cnt.chA_vol.read()) @as(u4, 2) else 1;
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const chB_sample = self.chB.amplitude() << if (self.dma_cnt.chB_vol.read()) @as(u4, 2) else 1;
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// Sample Dma Channels
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const chA_sample = if (self.dma_cnt.chA_vol.read()) self.chA.amplitude() * 4 else self.chA.amplitude() * 2;
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const chA_left = if (self.dma_cnt.chA_left.read()) chA_sample else 0;
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const chA_right = if (self.dma_cnt.chA_right.read()) chA_sample else 0;
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left += if (self.dma_cnt.chA_left.read()) chA_sample else 0;
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left += if (self.dma_cnt.chB_left.read()) chB_sample else 0;
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const chB_sample = if (self.dma_cnt.chB_vol.read()) self.chB.amplitude() * 4 else self.chB.amplitude() * 2;
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const chB_left = if (self.dma_cnt.chB_left.read()) chB_sample else 0;
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const chB_right = if (self.dma_cnt.chB_right.read()) chB_sample else 0;
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right += if (self.dma_cnt.chA_right.read()) chA_sample else 0;
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right += if (self.dma_cnt.chB_right.read()) chB_sample else 0;
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// Mix all Channels
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const left = (chA_left + chB_left + psg_left) / 6.0;
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const right = (chA_right + chB_right + psg_right) / 6.0;
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// Add SOUNDBIAS
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// FIXME: Is SOUNDBIAS 9-bit or 10-bit?
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const bias = @as(i16, self.bias.level.read()) << 1;
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left += bias;
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right += bias;
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const tmp_left = std.math.clamp(@intCast(u16, left), std.math.minInt(u11), std.math.maxInt(u11));
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const tmp_right = std.math.clamp(@intCast(u16, left), std.math.minInt(u11), std.math.maxInt(u11));
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// Extend to 16-bit signed audio samples
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const final_left = (tmp_left << 5) | (tmp_left >> 6);
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const final_right = (tmp_right << 5) | (tmp_right >> 6);
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if (self.sampling_cycle != self.bias.sampling_cycle.read()) {
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log.info("Sampling Cycle changed from {} to {}", .{ self.sampling_cycle, self.bias.sampling_cycle.read() });
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@ -201,15 +197,92 @@ pub const Apu = struct {
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defer SDL.SDL_FreeAudioStream(old);
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self.sampling_cycle = self.bias.sampling_cycle.read();
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self.stream = SDL.SDL_NewAudioStream(SDL.AUDIO_F32, 2, @intCast(c_int, self.sampleRate()), SDL.AUDIO_F32, 2, host_sample_rate) orelse unreachable;
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self.stream = SDL.SDL_NewAudioStream(SDL.AUDIO_U16, 2, @intCast(c_int, self.sampleRate()), SDL.AUDIO_U16, 2, host_sample_rate) orelse unreachable;
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}
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while (SDL.SDL_AudioStreamAvailable(self.stream) > (@sizeOf(f32) * 2 * 0x800)) {}
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while (SDL.SDL_AudioStreamAvailable(self.stream) > (@sizeOf(i16) * 2 * 0x800)) {}
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_ = SDL.SDL_AudioStreamPut(self.stream, &[2]f32{ left, right }, 2 * @sizeOf(f32));
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_ = SDL.SDL_AudioStreamPut(self.stream, &[2]u16{ final_left, final_right }, 2 * @sizeOf(u16));
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self.sched.push(.SampleAudio, self.sampleTicks() -| late);
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}
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// pub fn sampleAudio(self: *Self, late: u64) void {
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// // zig fmt: off
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// const any_ch_enabled = self.ch1.enabled
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// or self.ch2.enabled
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// or self.ch3.enabled
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// or self.ch4.enabled;
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// // zig fmt: on
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// const ch_left: u4 = self.psg_cnt.ch_left.read();
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// const ch_right: u4 = self.psg_cnt.ch_right.read();
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// // FIXME: Obscure behaviour?
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// // Apply NR50 Volume Modifications
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// const left_master_vol = (@intToFloat(f32, self.psg_cnt.left_vol.read()) + 1.0) / 7.0;
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// const right_master_vol = (@intToFloat(f32, self.psg_cnt.right_vol.read()) + 1.0) / 7.0;
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// // Apply SOUNDCNT_H Volume Modifications
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// const gba_vol: f32 = switch (self.dma_cnt.ch_vol.read()) {
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// 0b00 => 0.25,
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// 0b01 => 0.5,
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// else => 1.0,
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// };
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// // Sample Channel 1
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// const ch1_sample = self.highPass(self.ch1.amplitude(), any_ch_enabled);
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// const ch1_left = if (ch_left & 1 == 1) ch1_sample else 0;
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// const ch1_right = if (ch_right & 1 == 1) ch1_sample else 0;
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// // Sample Channel 2
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// const ch2_sample = self.highPass(self.ch2.amplitude(), any_ch_enabled);
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// const ch2_left = if (ch_left >> 1 & 1 == 1) ch2_sample else 0;
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// const ch2_right = if (ch_right >> 1 & 1 == 1) ch2_sample else 0;
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// // Sample Channel 3
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// const ch3_sample = self.highPass(self.ch3.amplitude(), any_ch_enabled);
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// const ch3_left = if (ch_left >> 2 & 1 == 1) ch3_sample else 0;
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// const ch3_right = if (ch_right >> 2 & 1 == 1) ch3_sample else 0;
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// // Sample Channel 4
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// const ch4_sample = self.highPass(self.ch4.amplitude(), any_ch_enabled);
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// const ch4_left = if (ch_left >> 3 == 1) ch4_sample else 0;
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// const ch4_right = if (ch_right >> 3 == 1) ch4_sample else 0;
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// const psg_left = (ch1_left + ch2_left + ch3_left + ch4_left) * left_master_vol * gba_vol;
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// const psg_right = (ch1_right + ch2_right + ch3_right + ch4_right) * right_master_vol * gba_vol;
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// // Sample Dma Channels
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// const chA_sample = if (self.dma_cnt.chA_vol.read()) self.chA.amplitude() * 4 else self.chA.amplitude() * 2;
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// const chA_left = if (self.dma_cnt.chA_left.read()) chA_sample else 0;
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// const chA_right = if (self.dma_cnt.chA_right.read()) chA_sample else 0;
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// const chB_sample = if (self.dma_cnt.chB_vol.read()) self.chB.amplitude() * 4 else self.chB.amplitude() * 2;
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// const chB_left = if (self.dma_cnt.chB_left.read()) chB_sample else 0;
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// const chB_right = if (self.dma_cnt.chB_right.read()) chB_sample else 0;
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// // Mix all Channels
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// const left = (chA_left + chB_left + psg_left) / 6.0;
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// const right = (chA_right + chB_right + psg_right) / 6.0;
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// if (self.sampling_cycle != self.bias.sampling_cycle.read()) {
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// log.info("Sampling Cycle changed from {} to {}", .{ self.sampling_cycle, self.bias.sampling_cycle.read() });
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// // Sample Rate Changed, Create a new Resampler since i can't figure out how to change
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// // the parameters of the old one
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// const old = self.stream;
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// defer SDL.SDL_FreeAudioStream(old);
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// self.sampling_cycle = self.bias.sampling_cycle.read();
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// self.stream = SDL.SDL_NewAudioStream(SDL.AUDIO_F32, 2, @intCast(c_int, self.sampleRate()), SDL.AUDIO_F32, 2, host_sample_rate) orelse unreachable;
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// }
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// while (SDL.SDL_AudioStreamAvailable(self.stream) > (@sizeOf(f32) * 2 * 0x800)) {}
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// _ = SDL.SDL_AudioStreamPut(self.stream, &[2]f32{ left, right }, 2 * @sizeOf(f32));
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// self.sched.push(.SampleAudio, self.sampleTicks() -| late);
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// }
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fn sampleTicks(self: *const Self) u64 {
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return (1 << 24) / self.sampleRate();
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}
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@ -296,7 +369,7 @@ const ToneSweep = struct {
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square: SquareWave,
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enabled: bool,
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sample: u8,
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sample: i8,
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const SweepDevice = struct {
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const This = @This();
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@ -389,11 +462,11 @@ const ToneSweep = struct {
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self.sample = 0;
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if (!self.isDacEnabled()) return;
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self.sample = if (self.enabled) self.square.sample(self.duty) * self.env_dev.vol else 0;
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self.sample = if (self.enabled) self.square.sample(self.duty) * @as(i8, self.env_dev.vol) else 0;
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}
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fn amplitude(self: *const Self) f32 {
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return (@intToFloat(f32, self.sample) / 7.5) - 1.0;
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fn amplitude(self: *const Self) i16 {
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return @as(i16, self.sample);
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}
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/// NR11, NR12
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@ -484,7 +557,7 @@ const Tone = struct {
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square: SquareWave,
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enabled: bool,
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sample: u8,
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sample: i8,
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fn init(sched: *Scheduler) Self {
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return .{
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@ -523,11 +596,11 @@ const Tone = struct {
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self.sample = 0;
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if (!self.isDacEnabled()) return;
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self.sample = if (self.enabled) self.square.sample(self.duty) * self.env_dev.vol else 0;
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self.sample = if (self.enabled) self.square.sample(self.duty) * @as(i8, self.env_dev.vol) else 0;
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}
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fn amplitude(self: *const Self) f32 {
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return (@intToFloat(f32, self.sample) / 7.5) - 1.0;
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fn amplitude(self: *const Self) i16 {
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return @as(i16, self.sample);
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}
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/// NR21, NR22
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@ -609,7 +682,7 @@ const Wave = struct {
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wave_dev: WaveDevice,
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enabled: bool,
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sample: u8,
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sample: i8,
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fn init(sched: *Scheduler) Self {
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return .{
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@ -696,11 +769,12 @@ const Wave = struct {
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self.sample = 0;
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if (!self.select.enabled.read()) return;
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self.sample = if (self.enabled) self.wave_dev.sample(self.select) >> self.wave_dev.shift(self.vol) else 0;
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// Convert unsigned 4-bit wave sample to signed 8-bit sample
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self.sample = (2 * @as(i8, self.wave_dev.sample(self.select)) - 15) >> self.wave_dev.shift(self.vol);
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}
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fn amplitude(self: *const Self) f32 {
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return (@intToFloat(f32, self.sample) / 7.5) - 1.0;
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fn amplitude(self: *const Self) i16 {
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return @as(i16, self.sample);
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}
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};
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@ -727,7 +801,7 @@ const Noise = struct {
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lfsr: Lfsr,
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enabled: bool,
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sample: u8,
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sample: i8,
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fn init(sched: *Scheduler) Self {
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return .{
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@ -821,11 +895,11 @@ const Noise = struct {
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self.sample = 0;
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if (!self.isDacEnabled()) return;
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self.sample = if (self.enabled) self.lfsr.sample() * self.env_dev.vol else 0;
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self.sample = if (self.enabled) self.lfsr.sample() * @as(i8, self.env_dev.vol) else 0;
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}
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fn amplitude(self: *const Self) f32 {
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return (@intToFloat(f32, self.sample) / 7.5) - 1.0;
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fn amplitude(self: *const Self) i16 {
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return @as(i16, self.sample);
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}
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fn isDacEnabled(self: *const Self) bool {
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@ -861,8 +935,8 @@ pub fn DmaSound(comptime kind: DmaSoundKind) type {
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if (self.fifo.readItem()) |sample| self.sample = @bitCast(i8, sample);
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}
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pub fn amplitude(self: *const Self) f32 {
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return @intToFloat(f32, self.sample) / 127.5 - (1 / 255);
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pub fn amplitude(self: *const Self) i16 {
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return @as(i16, self.sample);
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}
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};
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}
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@ -1100,7 +1174,7 @@ const SquareWave = struct {
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self.sched.push(.{ .ApuChannel = if (kind == .Ch1) 0 else 1 }, @as(u64, self.timer) * tickInterval);
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}
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fn sample(self: *const Self, cnt: io.Duty) u1 {
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fn sample(self: *const Self, cnt: io.Duty) i8 {
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const pattern = cnt.pattern.read();
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const i = self.pos ^ 7; // index of 0 should get highest bit
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@ -1111,7 +1185,7 @@ const SquareWave = struct {
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0b11 => @as(u8, 0b11111100) >> i, // 75%
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};
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return @truncate(u1, result);
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return if (result & 1 == 1) 1 else -1;
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}
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};
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@ -1133,8 +1207,8 @@ const Lfsr = struct {
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};
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}
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fn sample(self: *const Self) u1 {
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return @truncate(u1, ~self.shift);
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fn sample(self: *const Self) i8 {
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return if ((~self.shift & 1) == 1) 1 else -1;
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}
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fn updateLength(_: *Self, fs: *const FrameSequencer, ch4: *Noise, new: io.NoiseControl) void {
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@ -245,7 +245,7 @@ fn initAudio(apu: *Apu) SDL.SDL_AudioDeviceID {
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var have: SDL.SDL_AudioSpec = undefined;
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var want: SDL.SDL_AudioSpec = .{
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.freq = sample_rate,
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.format = SDL.AUDIO_F32,
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.format = SDL.AUDIO_U16,
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.channels = 2,
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.samples = 0x100,
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.callback = audioCallback,
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