Set up CMake build systemHEADmaster

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