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-rw-r--r--src/audio/audio.cpp23
-rw-r--r--src/audio/dct.h6
-rw-r--r--src/audio/fdct.cpp17
-rw-r--r--src/audio/idct.cpp17
-rw-r--r--src/audio/synth.cpp157
-rw-r--r--src/audio/synth.h24
-rw-r--r--src/audio/window.cpp9
-rw-r--r--src/audio/window.h5
8 files changed, 244 insertions, 14 deletions
diff --git a/src/audio/audio.cpp b/src/audio/audio.cpp
index 9e778f1..318ccb8 100644
--- a/src/audio/audio.cpp
+++ b/src/audio/audio.cpp
@@ -1,27 +1,19 @@
#define MINIAUDIO_IMPLEMENTATION
#include "miniaudio.h"
+#include "synth.h"
#include <math.h>
static ma_device device;
-static float phase = 0.0f;
static void audio_callback(ma_device*, void* output, const void*, ma_uint32 frames) {
- int16_t* out = (int16_t*)output;
- const float freq = 440.0f;
- const float sr = 32000.0f;
-
- for (ma_uint32 i = 0; i < frames; i++) {
- float s = sinf(phase) * 0.2f;
- phase += 2.0f * 3.14159265f * freq / sr;
- if (phase > 2.0f * 3.14159265f) phase -= 2.0f * 3.14159265f;
- out[i] = (int16_t)(s * 32767.0f);
- }
+ synth_render((float*)output, frames);
}
void audio_init() {
+ synth_init();
ma_device_config cfg = ma_device_config_init(ma_device_type_playback);
- cfg.playback.format = ma_format_s16;
- cfg.playback.channels = 1;
+ cfg.playback.format = ma_format_f32;
+ cfg.playback.channels = 2;
cfg.sampleRate = 32000;
cfg.dataCallback = audio_callback;
@@ -30,4 +22,7 @@ void audio_init() {
}
void audio_update() {}
-void audio_shutdown() { ma_device_uninit(&device); }
+void audio_shutdown() {
+ synth_shutdown();
+ ma_device_uninit(&device);
+}
diff --git a/src/audio/dct.h b/src/audio/dct.h
new file mode 100644
index 0000000..3e51884
--- /dev/null
+++ b/src/audio/dct.h
@@ -0,0 +1,6 @@
+#pragma once
+
+#define DCT_SIZE 512
+
+void fdct_512(const float input[DCT_SIZE], float output[DCT_SIZE]);
+void idct_512(const float input[DCT_SIZE], float output[DCT_SIZE]);
diff --git a/src/audio/fdct.cpp b/src/audio/fdct.cpp
new file mode 100644
index 0000000..50ab458
--- /dev/null
+++ b/src/audio/fdct.cpp
@@ -0,0 +1,17 @@
+#include "dct.h"
+#include "util/math.h"
+#include <math.h>
+
+void fdct_512(const float input[DCT_SIZE], float output[DCT_SIZE]) {
+ float scale_k0 = sqrtf(1.0f / DCT_SIZE);
+ float scale_kn = sqrtf(2.0f / DCT_SIZE);
+
+ for (int k = 0; k < DCT_SIZE; ++k) {
+ float sum = 0.0f;
+ for (int n = 0; n < DCT_SIZE; ++n) {
+ sum += input[n] * cosf((PI / DCT_SIZE) * (n + 0.5f) * k);
+ }
+ float scale = (k == 0) ? scale_k0 : scale_kn;
+ output[k] = sum * scale;
+ }
+}
diff --git a/src/audio/idct.cpp b/src/audio/idct.cpp
new file mode 100644
index 0000000..a32f92e
--- /dev/null
+++ b/src/audio/idct.cpp
@@ -0,0 +1,17 @@
+#include "dct.h"
+#include "util/math.h"
+#include <math.h>
+
+void idct_512(const float input[DCT_SIZE], float output[DCT_SIZE]) {
+ float scale_k0 = sqrtf(1.0f / DCT_SIZE);
+ float scale_kn = sqrtf(2.0f / DCT_SIZE);
+
+ for (int n = 0; n < DCT_SIZE; ++n) {
+ float sum = 0.0f;
+ for (int k = 0; k < DCT_SIZE; ++k) {
+ float scale = (k == 0) ? scale_k0 : scale_kn;
+ sum += scale * input[k] * cosf((PI / DCT_SIZE) * (n + 0.5f) * k);
+ }
+ output[n] = sum;
+ }
+}
diff --git a/src/audio/synth.cpp b/src/audio/synth.cpp
new file mode 100644
index 0000000..f009876
--- /dev/null
+++ b/src/audio/synth.cpp
@@ -0,0 +1,157 @@
+#include "synth.h"
+#include "audio/window.h"
+#include <string.h> // For memset
+#include <atomic>
+
+struct Voice {
+ bool active;
+ int spectrogram_id;
+ float volume;
+ float pan_left;
+ float pan_right;
+
+ int current_spectral_frame;
+ int total_spectral_frames;
+
+ float time_domain_buffer[DCT_SIZE];
+ int buffer_pos;
+
+ const volatile float* active_spectral_data;
+};
+
+static struct {
+ Spectrogram spectrograms[MAX_SPECTROGRAMS];
+ const volatile float* active_spectrogram_data[MAX_SPECTROGRAMS];
+ bool spectrogram_registered[MAX_SPECTROGRAMS];
+} g_synth_data;
+
+static Voice g_voices[MAX_VOICES];
+
+void synth_init() {
+ memset(&g_synth_data, 0, sizeof(g_synth_data));
+ memset(g_voices, 0, sizeof(g_voices));
+}
+
+void synth_shutdown() {
+ // Nothing to do here since we are not allocating memory
+}
+
+int synth_register_spectrogram(const Spectrogram* spec) {
+ for (int i = 0; i < MAX_SPECTROGRAMS; ++i) {
+ if (!g_synth_data.spectrogram_registered[i]) {
+ g_synth_data.spectrograms[i] = *spec;
+ g_synth_data.active_spectrogram_data[i] = spec->spectral_data_a;
+ g_synth_data.spectrogram_registered[i] = true;
+ return i;
+ }
+ }
+ return -1; // No free slots
+}
+
+void synth_unregister_spectrogram(int spectrogram_id) {
+ if (spectrogram_id >= 0 && spectrogram_id < MAX_SPECTROGRAMS) {
+ g_synth_data.spectrogram_registered[spectrogram_id] = false;
+ }
+}
+
+float* synth_begin_update(int spectrogram_id) {
+ if (spectrogram_id < 0 || spectrogram_id >= MAX_SPECTROGRAMS || !g_synth_data.spectrogram_registered[spectrogram_id]) {
+ return nullptr;
+ }
+
+ const volatile float* active_ptr = g_synth_data.active_spectrogram_data[spectrogram_id];
+
+ if (active_ptr == g_synth_data.spectrograms[spectrogram_id].spectral_data_a) {
+ return g_synth_data.spectrograms[spectrogram_id].spectral_data_b;
+ } else {
+ return g_synth_data.spectrograms[spectrogram_id].spectral_data_a;
+ }
+}
+
+void synth_commit_update(int spectrogram_id) {
+ if (spectrogram_id < 0 || spectrogram_id >= MAX_SPECTROGRAMS || !g_synth_data.spectrogram_registered[spectrogram_id]) {
+ return;
+ }
+
+ const volatile float* old_active_ptr = g_synth_data.active_spectrogram_data[spectrogram_id];
+ const float* new_active_ptr = (old_active_ptr == g_synth_data.spectrograms[spectrogram_id].spectral_data_a)
+ ? g_synth_data.spectrograms[spectrogram_id].spectral_data_b
+ : g_synth_data.spectrograms[spectrogram_id].spectral_data_a;
+
+ // Atomic swap using GCC/Clang builtins for thread safety
+ __atomic_store_n((const float**)&g_synth_data.active_spectrogram_data[spectrogram_id], new_active_ptr, __ATOMIC_RELEASE);
+}
+
+
+void synth_trigger_voice(int spectrogram_id, float volume, float pan) {
+ if (spectrogram_id < 0 || spectrogram_id >= MAX_SPECTROGRAMS || !g_synth_data.spectrogram_registered[spectrogram_id]) {
+ return;
+ }
+
+ for (int i = 0; i < MAX_VOICES; ++i) {
+ if (!g_voices[i].active) {
+ Voice& v = g_voices[i];
+ v.active = true;
+ v.spectrogram_id = spectrogram_id;
+ v.volume = volume;
+
+ // Simple linear panning
+ v.pan_left = (pan > 0.0f) ? (1.0f - pan) : 1.0f;
+ v.pan_right = (pan < 0.0f) ? (1.0f + pan) : 1.0f;
+
+ v.current_spectral_frame = 0;
+ v.total_spectral_frames = g_synth_data.spectrograms[spectrogram_id].num_frames;
+ v.buffer_pos = DCT_SIZE; // Force IDCT on first render
+ v.active_spectral_data = g_synth_data.active_spectrogram_data[spectrogram_id];
+
+ return; // Voice triggered
+ }
+ }
+}
+
+
+void synth_render(float* output_buffer, int num_frames) {
+ float window[WINDOW_SIZE];
+ hamming_window_512(window);
+
+ for (int i = 0; i < num_frames; ++i) {
+ float left_sample = 0.0f;
+ float right_sample = 0.0f;
+
+ for (int v_idx = 0; v_idx < MAX_VOICES; ++v_idx) {
+ Voice& v = g_voices[v_idx];
+ if (!v.active) continue;
+
+ if (v.buffer_pos >= DCT_SIZE) {
+ if (v.current_spectral_frame >= v.total_spectral_frames) {
+ v.active = false;
+ continue;
+ }
+
+ // Fetch the latest active spectrogram pointer for this voice
+ v.active_spectral_data = g_synth_data.active_spectrogram_data[v.spectrogram_id];
+
+ const float* spectral_frame = (const float*)v.active_spectral_data + (v.current_spectral_frame * DCT_SIZE);
+
+ float windowed_frame[DCT_SIZE];
+ for(int j=0; j<DCT_SIZE; ++j) {
+ windowed_frame[j] = spectral_frame[j] * window[j];
+ }
+
+ idct_512(windowed_frame, v.time_domain_buffer);
+
+ v.buffer_pos = 0;
+ v.current_spectral_frame++;
+ }
+
+ float voice_sample = v.time_domain_buffer[v.buffer_pos] * v.volume;
+ left_sample += voice_sample * v.pan_left;
+ right_sample += voice_sample * v.pan_right;
+
+ v.buffer_pos++;
+ }
+
+ output_buffer[i * 2] = left_sample;
+ output_buffer[i * 2 + 1] = right_sample;
+ }
+}
diff --git a/src/audio/synth.h b/src/audio/synth.h
new file mode 100644
index 0000000..ce9825d
--- /dev/null
+++ b/src/audio/synth.h
@@ -0,0 +1,24 @@
+#pragma once
+
+#include "dct.h"
+
+#define MAX_SPECTROGRAMS 16
+#define MAX_VOICES 16
+
+struct Spectrogram {
+ float* spectral_data_a;
+ float* spectral_data_b;
+ int num_frames;
+};
+
+void synth_init();
+void synth_shutdown();
+
+int synth_register_spectrogram(const Spectrogram* spec);
+void synth_unregister_spectrogram(int spectrogram_id);
+
+float* synth_begin_update(int spectrogram_id);
+void synth_commit_update(int spectrogram_id);
+
+void synth_trigger_voice(int spectrogram_id, float volume, float pan);
+void synth_render(float* output_buffer, int num_frames);
diff --git a/src/audio/window.cpp b/src/audio/window.cpp
new file mode 100644
index 0000000..3f36480
--- /dev/null
+++ b/src/audio/window.cpp
@@ -0,0 +1,9 @@
+#include "window.h"
+#include "util/math.h"
+#include <math.h>
+
+void hamming_window_512(float window[WINDOW_SIZE]) {
+ for (int i = 0; i < WINDOW_SIZE; ++i) {
+ window[i] = 0.54f - 0.46f * cosf(2.0f * PI * i / (WINDOW_SIZE - 1));
+ }
+}
diff --git a/src/audio/window.h b/src/audio/window.h
new file mode 100644
index 0000000..8cb5dd8
--- /dev/null
+++ b/src/audio/window.h
@@ -0,0 +1,5 @@
+#pragma once
+
+#define WINDOW_SIZE 512
+
+void hamming_window_512(float window[WINDOW_SIZE]);
generated by cgit v1.2.3 (git 2.51.0) at 2026-02-05 12:35:48 +0000