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UI controls in emulator

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Dejvino
2026-02-27 20:20:06 +01:00
parent 2b6e1d2c6b
commit 5240eb990b
3 changed files with 204 additions and 18 deletions
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main.cpp
+134 -6
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@@ -3,6 +3,7 @@
#include <SDL2/SDL.h>
#include <vector>
#include <atomic>
#include <math.h>
#include "synth_engine.h" // Include our portable engine
#include <stdio.h>
@@ -18,6 +19,15 @@ const size_t VIS_BUFFER_SIZE = 8192;
std::vector<int16_t> vis_buffer(VIS_BUFFER_SIZE, 0);
std::atomic<size_t> vis_write_index{0};
// --- Control State ---
const float MIN_FREQ = 20.0f;
const float MAX_FREQ = 20000.0f;
float knob_freq_val = 440.0f;
float knob_vol_val = 0.5f;
SynthEngine::Waveform current_waveform = SynthEngine::SAWTOOTH;
const char* waveform_names[] = {"Saw", "Square", "Sine"};
// --- Global Synth Engine Instance ---
// The audio callback needs access to our synth, so we make it global.
SynthEngine engine(SAMPLE_RATE);
@@ -47,6 +57,78 @@ void data_callback(ma_device* pDevice, void* pOutput, const void* pInput, ma_uin
vis_write_index.store(idx, std::memory_order_relaxed);
}
// --- UI Drawing Helpers ---
void DrawCircle(SDL_Renderer * renderer, int32_t centreX, int32_t centreY, int32_t radius) {
const int32_t diameter = (radius * 2);
int32_t x = (radius - 1);
int32_t y = 0;
int32_t tx = 1;
int32_t ty = 1;
int32_t error = (tx - diameter);
while (x >= y) {
SDL_RenderDrawPoint(renderer, centreX + x, centreY - y);
SDL_RenderDrawPoint(renderer, centreX + x, centreY + y);
SDL_RenderDrawPoint(renderer, centreX - x, centreY - y);
SDL_RenderDrawPoint(renderer, centreX - x, centreY + y);
SDL_RenderDrawPoint(renderer, centreX + y, centreY - x);
SDL_RenderDrawPoint(renderer, centreX + y, centreY + x);
SDL_RenderDrawPoint(renderer, centreX - y, centreY - x);
SDL_RenderDrawPoint(renderer, centreX - y, centreY + x);
if (error <= 0) {
++y;
error += ty;
ty += 2;
}
if (error > 0) {
--x;
tx += 2;
error += (tx - diameter);
}
}
}
void drawKnob(SDL_Renderer* renderer, int x, int y, int radius, float value) {
// Draw outline
SDL_SetRenderDrawColor(renderer, 100, 100, 100, 255);
DrawCircle(renderer, x, y, radius);
DrawCircle(renderer, x, y, radius-1);
// Draw indicator
float angle = (value * (270.0f * M_PI / 180.0f)) - (135.0f * M_PI / 180.0f);
int x2 = x + (int)(sin(angle) * (radius - 2));
int y2 = y - (int)(cos(angle) * (radius - 2));
SDL_SetRenderDrawColor(renderer, 255, 255, 255, 255);
SDL_RenderDrawLine(renderer, x, y, x2, y2);
}
void drawWaveformIcon(SDL_Renderer* renderer, int x, int y, int w, int h, SynthEngine::Waveform wf) {
SDL_SetRenderDrawColor(renderer, 200, 200, 200, 255);
switch(wf) {
case SynthEngine::SAWTOOTH:
SDL_RenderDrawLine(renderer, x, y+h, x+w, y); // Ramp up
SDL_RenderDrawLine(renderer, x+w, y, x+w, y+h); // Drop down
break;
case SynthEngine::SQUARE:
SDL_RenderDrawLine(renderer, x, y+h, x, y); // Rise
SDL_RenderDrawLine(renderer, x, y, x+w, y); // High
SDL_RenderDrawLine(renderer, x+w, y, x+w, y+h); // Drop
break;
case SynthEngine::SINE: {
int prev_x = x, prev_y = y + h/2;
for (int i = 1; i <= w; ++i) {
int px = x + i;
int py = y + h/2 - (int)(sin(i * 2.0 * M_PI / w) * h/2.0f);
SDL_RenderDrawLine(renderer, prev_x, prev_y, px, py);
prev_x = px; prev_y = py;
}
break;
}
}
}
int main(int argc, char* argv[]) {
(void)argc; (void)argv;
@@ -81,6 +163,9 @@ int main(int argc, char* argv[]) {
ma_device_start(&device);
engine.setVolume(knob_vol_val);
engine.setFrequency(knob_freq_val);
// --- Main Loop ---
bool quit = false;
SDL_Event e;
@@ -89,14 +174,50 @@ int main(int argc, char* argv[]) {
while (SDL_PollEvent(&e) != 0) {
if (e.type == SDL_QUIT) {
quit = true;
} else if (e.type == SDL_MOUSEWHEEL) {
int mouseX, mouseY;
SDL_GetMouseState(&mouseX, &mouseY);
if (mouseX < WINDOW_WIDTH / 2) { // Left knob (frequency)
if (e.wheel.y > 0) knob_freq_val *= 1.05f;
else if (e.wheel.y < 0) knob_freq_val /= 1.05f;
if (knob_freq_val < MIN_FREQ) knob_freq_val = MIN_FREQ;
if (knob_freq_val > MAX_FREQ) knob_freq_val = MAX_FREQ;
engine.setFrequency(knob_freq_val);
} else { // Right knob (volume)
if (e.wheel.y > 0) knob_vol_val += 0.05f;
else if (e.wheel.y < 0) knob_vol_val -= 0.05f;
if (knob_vol_val > 1.0f) knob_vol_val = 1.0f;
if (knob_vol_val < 0.0f) knob_vol_val = 0.0f;
engine.setVolume(knob_vol_val);
}
} else if (e.type == SDL_MOUSEBUTTONDOWN) {
int mouseX, mouseY;
SDL_GetMouseState(&mouseX, &mouseY);
if (e.button.button == SDL_BUTTON_LEFT && mouseX < WINDOW_WIDTH / 2) {
// Left knob click emulates encoder switch: cycle waveform
current_waveform = (SynthEngine::Waveform)(((int)current_waveform + 1) % 3);
engine.setWaveform(current_waveform);
}
}
}
// Update window title with current values
char title[128];
snprintf(title, sizeof(title), "NoiceSynth Scope | Freq: %.1f Hz | Vol: %.0f%% | Wave: %s",
knob_freq_val,
knob_vol_val * 100.0f,
waveform_names[(int)current_waveform]);
SDL_SetWindowTitle(window, title);
// Clear screen
SDL_SetRenderDrawColor(renderer, 0, 0, 0, 255);
SDL_RenderClear(renderer);
// Draw Waveform
// --- Draw Waveform (Oscilloscope) ---
// Draw in the top half of the window
SDL_SetRenderDrawColor(renderer, 0, 255, 0, 255); // Green
// Determine read position (snapshot atomic write index)
@@ -121,24 +242,31 @@ int main(int argc, char* argv[]) {
}
// Draw points
int prev_x = 0;
int prev_y = WINDOW_HEIGHT / 2;
int prev_x = -1;
int prev_y = -1;
for (int x = 0; x < WINDOW_WIDTH; ++x) {
int16_t sample = vis_buffer[read_idx];
read_idx = (read_idx + 1) % VIS_BUFFER_SIZE;
// Map 16-bit sample (-32768 to 32767) to screen height
// Invert Y because screen Y grows downwards
int y = WINDOW_HEIGHT / 2 - (sample * (WINDOW_HEIGHT / 2) / 32768);
// Use top half of window, so divide height by 4 (2 for half, 2 for +/-)
int y = WINDOW_HEIGHT / 4 - (sample * (WINDOW_HEIGHT / 4) / 32768);
if (x > 0) {
if (prev_x != -1) {
SDL_RenderDrawLine(renderer, prev_x, prev_y, x, y);
}
prev_x = x;
prev_y = y;
}
// --- Draw Controls ---
// Draw in the bottom half of the window
float normalized_freq = (log(knob_freq_val) - log(MIN_FREQ)) / (log(MAX_FREQ) - log(MIN_FREQ));
drawKnob(renderer, WINDOW_WIDTH / 4, WINDOW_HEIGHT * 3 / 4, 50, normalized_freq);
drawWaveformIcon(renderer, WINDOW_WIDTH / 4 - 25, WINDOW_HEIGHT * 3 / 4 + 60, 50, 20, current_waveform);
drawKnob(renderer, WINDOW_WIDTH * 3 / 4, WINDOW_HEIGHT * 3 / 4, 50, knob_vol_val);
SDL_RenderPresent(renderer);
}