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-rw-r--r--src/audio.cpp88
-rw-r--r--src/audio.h24
-rw-r--r--src/gui.cpp77
-rw-r--r--src/gui.h37
-rw-r--r--src/main.cpp57
-rw-r--r--src/sequence.h12
6 files changed, 295 insertions, 0 deletions
diff --git a/src/audio.cpp b/src/audio.cpp
new file mode 100644
index 0000000..db915e1
--- /dev/null
+++ b/src/audio.cpp
@@ -0,0 +1,88 @@
+#include "audio.h"
+
+#define _USE_MATH_DEFINES
+#include <cmath>
+#include <iostream>
+#include <SDL.h>
+
+#include "sequence.h"
+
+static const float AMPLITUDE = 0.2f;
+
+// SDL periodically calls this function to fill a chunk of the audio output buffer
+static void AudioCallback(void* userData, Uint8* rawBuffer, int bytes)
+{
+ float* buffer = (float*)rawBuffer;
+ int length = bytes / sizeof(float);
+ CallbackInfo* info = (CallbackInfo*)userData;
+ StepData& step = info->seq->steps[info->currentStep];
+
+ for (int i = 0; i < length; i++, info->samplesDone++) {
+ float time = (float)info->samplesDone / (float)info->sampleRate;
+ float modWave = sinf(2.0f * M_PI * step.modFreq * time);
+ float freq = step.carrierFreq + modWave * step.modDepth;
+
+ // Check if enough samples have been generated for this step
+ if (info->samplesDone >= info->samplesPerStep) {
+ // If so, move on to the next step
+ info->samplesDone = 0;
+ step = info->seq->steps[info->currentStep];
+ info->currentStep = (info->currentStep + 1) % 8;
+ }
+
+ buffer[i] = (sinf(2.0f * M_PI * freq * time)) * AMPLITUDE;
+ }
+}
+
+AudioContext::AudioContext(Sequence& seq)
+{
+ SDL_AudioSpec desiredSpec;
+ desiredSpec.freq = 44100;
+ desiredSpec.format = AUDIO_F32SYS;
+ desiredSpec.channels = 1;
+ desiredSpec.samples = 2048;
+ desiredSpec.callback = AudioCallback;
+ desiredSpec.userdata = &m_info;
+
+ SDL_AudioSpec obtainedSpec;
+ if (SDL_OpenAudio(&desiredSpec, &obtainedSpec) < 0) {
+ std::cerr << "Failed to initalize audio! " << SDL_GetError() << std::endl;
+ std::exit(1);
+ }
+
+ // The audio callback expects float values, so if a different data type
+ // is obtained we should throw an error.
+ if (desiredSpec.format != obtainedSpec.format) {
+ std::cerr << "Unexpected audio format: " << obtainedSpec.format << std::endl;
+ std::exit(1);
+ }
+
+ m_info.samplesDone = 0;
+ m_info.samplesPerStep = obtainedSpec.freq * 0.4f;
+ m_info.currentStep = 0;
+ m_info.sampleRate = obtainedSpec.freq;
+ m_info.seq = &seq;
+
+ this->Start();
+}
+
+AudioContext::~AudioContext()
+{
+ this->Stop();
+ SDL_CloseAudio();
+}
+
+void AudioContext::Start()
+{
+ SDL_PauseAudio(0);
+}
+
+void AudioContext::Stop()
+{
+ SDL_PauseAudio(1);
+}
+
+int AudioContext::CurrentStep()
+{
+ return m_info.currentStep;
+} \ No newline at end of file
diff --git a/src/audio.h b/src/audio.h
new file mode 100644
index 0000000..6205de7
--- /dev/null
+++ b/src/audio.h
@@ -0,0 +1,24 @@
+#pragma once
+
+class Sequence;
+
+struct CallbackInfo {
+ int samplesDone;
+ int samplesPerStep;
+ int currentStep;
+ int sampleRate;
+ Sequence* seq;
+};
+
+class AudioContext {
+public:
+ AudioContext(Sequence&);
+ ~AudioContext();
+
+ void Start();
+ void Stop();
+
+ int CurrentStep();
+private:
+ CallbackInfo m_info;
+}; \ No newline at end of file
diff --git a/src/gui.cpp b/src/gui.cpp
new file mode 100644
index 0000000..fcd4511
--- /dev/null
+++ b/src/gui.cpp
@@ -0,0 +1,77 @@
+#include "gui.h"
+
+#include "sequence.h"
+
+void Slider::Draw(SDL_Renderer* renderer)
+{
+ SDL_RenderDrawRect(renderer, &m_bounds);
+ SDL_RenderDrawLine(renderer, m_bounds.x, m_bounds.y + (*value * valueScaling), m_bounds.x + m_bounds.w, m_bounds.y + (*value * valueScaling));
+}
+
+bool Slider::InBounds(int x, int y)
+{
+ SDL_Point point = { x, y };
+ return SDL_PointInRect(&point, &m_bounds);
+}
+
+GUI::GUI(Sequence& seq)
+ : m_sequence(seq)
+{
+ int i = 0;
+ for (auto& step : seq.steps) {
+ m_sliders.emplace_back(i * 40 + 14, 60, &step.carrierFreq, 0.1f);
+ m_sliders.emplace_back(i * 40 + 14, 145, &step.modFreq);
+ m_sliders.emplace_back(i * 40 + 14, 230, &step.modDepth, 3.0f);
+ i++;
+ }
+}
+
+void GUI::OnMouseDown(int x, int y)
+{
+ for (Slider& slider : m_sliders) {
+ if (slider.InBounds(x, y)) {
+ m_activeSlider = &slider;
+ m_dragStart = y;
+ return;
+ }
+ }
+}
+
+void GUI::OnMouseUp()
+{
+ m_activeSlider = nullptr;
+ m_dragStart = 0;
+}
+
+void GUI::OnMouseMove(int x, int y)
+{
+ if (m_activeSlider) {
+ *m_activeSlider->value -= (m_dragStart - y) / m_activeSlider->valueScaling;
+ m_dragStart = y;
+
+ if (*m_activeSlider->value < 0)
+ *m_activeSlider->value = 0;
+ }
+}
+
+void GUI::Repaint(SDL_Renderer* renderer, int currentStep)
+{
+ SDL_Rect rect = { 10, 10, 32, 32 };
+
+ for (int i = 0; i < 8; i++) {
+ SDL_SetRenderDrawColor(renderer, m_sequence.steps[i].modDepth * 8, m_sequence.steps[i].modFreq * 2, m_sequence.steps[i].carrierFreq / 3, 255);
+
+ if (i == currentStep)
+ SDL_RenderFillRect(renderer, &rect);
+ else
+ SDL_RenderDrawRect(renderer, &rect);
+
+ rect.x += rect.w + 8;
+ }
+
+ SDL_SetRenderDrawColor(renderer, 127, 127, 255, 255);
+
+ for (Slider& slider : m_sliders) {
+ slider.Draw(renderer);
+ }
+} \ No newline at end of file
diff --git a/src/gui.h b/src/gui.h
new file mode 100644
index 0000000..76a1128
--- /dev/null
+++ b/src/gui.h
@@ -0,0 +1,37 @@
+#pragma once
+
+#include <SDL.h>
+
+#include <vector>
+#include "sequence.h"
+
+class Slider {
+public:
+ Slider(int x, int y, float* valuePtr, float scaling = 1.f)
+ : m_bounds({ x, y, 25, 75 }), value(valuePtr), valueScaling(scaling) {}
+
+ void Draw(SDL_Renderer*);
+ bool InBounds(int x, int y);
+
+ float* value;
+ float valueScaling;
+private:
+ SDL_Rect m_bounds;
+};
+
+class GUI {
+public:
+ GUI(Sequence&);
+
+ void OnMouseDown(int x, int y);
+ void OnMouseUp();
+ void OnMouseMove(int x, int y);
+
+ void Repaint(SDL_Renderer*, int currentStep);
+private:
+ std::vector<Slider> m_sliders;
+
+ Sequence& m_sequence;
+ Slider* m_activeSlider{ nullptr };
+ int m_dragStart{ 0 };
+}; \ No newline at end of file
diff --git a/src/main.cpp b/src/main.cpp
new file mode 100644
index 0000000..6056442
--- /dev/null
+++ b/src/main.cpp
@@ -0,0 +1,57 @@
+#include <SDL.h>
+#include <iostream>
+
+#include "audio.h"
+#include "gui.h"
+#include "sequence.h"
+
+int main(int argc, char** argv)
+{
+ if (SDL_Init(SDL_INIT_VIDEO | SDL_INIT_AUDIO) < 0) {
+ std::cerr << "Failed to initalize SDL! " << SDL_GetError() << std::endl;
+ return 1;
+ }
+
+ SDL_Window* window = SDL_CreateWindow("fmseq", SDL_WINDOWPOS_UNDEFINED, SDL_WINDOWPOS_UNDEFINED, 640, 320, SDL_WINDOW_SHOWN);
+ SDL_Renderer* renderer = SDL_CreateRenderer(window, -1, SDL_RENDERER_ACCELERATED);
+ SDL_Event event;
+
+ Sequence sequence;
+ AudioContext audio(sequence);
+ GUI gui(sequence);
+
+ bool running = true;
+ while (running) {
+ while (SDL_PollEvent(&event)) {
+ switch (event.type) {
+ case SDL_QUIT:
+ running = false;
+ break;
+ case SDL_MOUSEBUTTONDOWN:
+ gui.OnMouseDown(event.button.x, event.button.y);
+ break;
+ case SDL_MOUSEMOTION:
+ gui.OnMouseMove(event.button.x, event.button.y);
+ break;
+ case SDL_MOUSEBUTTONUP:
+ gui.OnMouseUp();
+ break;
+ }
+ }
+
+ SDL_SetRenderDrawColor(renderer, 0, 0, 0, 255);
+ SDL_RenderClear(renderer);
+
+ gui.Repaint(renderer, audio.CurrentStep());
+
+ SDL_RenderPresent(renderer);
+ SDL_UpdateWindowSurface(window);
+
+ SDL_Delay(10);
+ }
+
+ SDL_DestroyWindow(window);
+ SDL_Quit();
+
+ return 0;
+} \ No newline at end of file
diff --git a/src/sequence.h b/src/sequence.h
new file mode 100644
index 0000000..decd9fd
--- /dev/null
+++ b/src/sequence.h
@@ -0,0 +1,12 @@
+#pragma once
+
+struct StepData {
+ float carrierFreq = 110.f;
+ float modFreq = 0;
+ float modDepth = 1;
+};
+
+class Sequence {
+public:
+ StepData steps[8];
+}; \ No newline at end of file
generated by cgit v1.2.3 (git 2.25.1) at 2025-05-25 19:30:17 +0000