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Grid synth engine

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Dejvino
2026-02-27 23:49:57 +01:00
parent f80daed222
commit e86c06e05f
3 changed files with 555 additions and 89 deletions
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synth_engine.cpp
+221 -20
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@@ -32,12 +32,27 @@ SynthEngine::SynthEngine(uint32_t sampleRate)
_sustainLevel(1.0f),
_releaseDec(0.0f),
_lpAlpha(1.0f), _hpAlpha(0.0f),
_lpVal(0.0f), _hpVal(0.0f)
_lpVal(0.0f), _hpVal(0.0f),
grid{}
{
fill_sine_table();
// Initialize with a default frequency
setFrequency(440.0f);
setADSR(0.05f, 0.1f, 0.7f, 0.2f); // Default envelope
// Initialize SINK
grid[2][3].type = GridCell::SINK;
}
SynthEngine::~SynthEngine() {
for (int x = 0; x < 5; ++x) {
for (int y = 0; y < 8; ++y) {
if (grid[x][y].buffer) {
delete[] grid[x][y].buffer;
grid[x][y].buffer = nullptr;
}
}
}
}
void SynthEngine::setFrequency(float freq) {
@@ -92,32 +107,218 @@ float SynthEngine::getFrequency() const {
return (float)((double)_increment * (double)_sampleRate / 4294967296.0);
}
void SynthEngine::process(int16_t* buffer, uint32_t numFrames) {
for (uint32_t i = 0; i < numFrames; ++i) {
_phase += _increment;
int16_t sample = 0;
float SynthEngine::processGridStep() {
// Double buffer for values to handle feedback loops gracefully (1-sample delay)
float next_values[5][8];
// Helper to get input from a neighbor
auto getInput = [&](int tx, int ty, int from_x, int from_y) -> float {
if (from_x < 0 || from_x >= 5 || from_y < 0 || from_y >= 8) return 0.0f;
GridCell& n = grid[from_x][from_y];
// Oscillator Generation
switch (_waveform) {
case SAWTOOTH:
sample = static_cast<int16_t>(_phase >> 16);
break;
case SQUARE:
sample = (_phase < 0x80000000) ? 32767 : -32768;
break;
case SINE:
sample = sine_table[(_phase >> 24) & 0xFF];
break;
// Check if neighbor outputs to (tx, ty)
bool connects = false;
if (n.type == GridCell::WIRE || n.type == GridCell::FIXED_OSCILLATOR || n.type == GridCell::INPUT_OSCILLATOR || n.type == GridCell::OPERATOR || n.type == GridCell::NOISE || n.type == GridCell::DELAY) {
// Check rotation
// 0:N (y-1), 1:E (x+1), 2:S (y+1), 3:W (x-1)
if (n.rotation == 0 && from_y - 1 == ty && from_x == tx) connects = true;
if (n.rotation == 1 && from_x + 1 == tx && from_y == ty) connects = true;
if (n.rotation == 2 && from_y + 1 == ty && from_x == tx) connects = true;
if (n.rotation == 3 && from_x - 1 == tx && from_y == ty) connects = true;
} else if (n.type == GridCell::FORK) {
// Fork outputs to Left (rot+3) and Right (rot+1) relative to its rotation
// n.rotation is "Forward"
int dx = tx - from_x;
int dy = ty - from_y;
int dir = -1;
if (dx == 0 && dy == -1) dir = 0; // N
if (dx == 1 && dy == 0) dir = 1; // E
if (dx == 0 && dy == 1) dir = 2; // S
if (dx == -1 && dy == 0) dir = 3; // W
int leftOut = (n.rotation + 3) % 4;
int rightOut = (n.rotation + 1) % 4;
if (dir == leftOut) return n.value * (1.0f - n.param) * 2.0f;
if (dir == rightOut) return n.value * n.param * 2.0f;
}
return connects ? n.value : 0.0f;
};
float sampleF = static_cast<float>(sample);
for (int x = 0; x < 5; ++x) {
for (int y = 0; y < 8; ++y) {
GridCell& c = grid[x][y];
float val = 0.0f;
if (c.type == GridCell::EMPTY) {
val = 0.0f;
} else if (c.type == GridCell::FIXED_OSCILLATOR) {
// Gather inputs for modulation
float mod = 0.0f;
mod += getInput(x, y, x, y-1);
mod += getInput(x, y, x+1, y);
mod += getInput(x, y, x, y+1);
mod += getInput(x, y, x-1, y);
// Freq 10 to 1000 Hz
float freq = 10.0f + c.param * 990.0f + (mod * 500.0f); // FM
if (freq < 1.0f) freq = 1.0f;
float inc = freq * (float)SINE_TABLE_SIZE / (float)_sampleRate;
c.phase += inc;
if (c.phase >= SINE_TABLE_SIZE) c.phase -= SINE_TABLE_SIZE;
val = (float)sine_table[(int)c.phase] / 32768.0f;
} else if (c.type == GridCell::INPUT_OSCILLATOR) {
float mod = 0.0f;
mod += getInput(x, y, x, y-1);
mod += getInput(x, y, x+1, y);
mod += getInput(x, y, x, y+1);
mod += getInput(x, y, x-1, y);
// Freq based on current note + octave param (1-5)
float baseFreq = getFrequency();
int octave = 1 + (int)(c.param * 4.99f); // Map 0.0-1.0 to 1-5
float freq = baseFreq * (float)(1 << (octave - 1)); // 2^(octave-1)
float inc = freq * (float)SINE_TABLE_SIZE / (float)_sampleRate;
c.phase += inc;
if (c.phase >= SINE_TABLE_SIZE) c.phase -= SINE_TABLE_SIZE;
val = (float)sine_table[(int)c.phase] / 32768.0f;
} else if (c.type == GridCell::NOISE) {
float white = (float)rand() / (float)RAND_MAX * 2.0f - 1.0f;
int shade = (int)(c.param * 4.99f);
switch(shade) {
case 0: // Brown (Leaky integrator)
c.phase = (c.phase + white * 0.1f) * 0.95f;
val = c.phase * 3.0f; // Gain up
break;
case 1: // Pink (Approx: LPF)
c.phase = 0.5f * c.phase + 0.5f * white;
val = c.phase;
break;
case 2: // White
val = white;
break;
case 3: // Yellow (HPF)
val = white - c.phase;
c.phase = white; // Store last sample
break;
case 4: // Green (BPF approx)
c.phase = (c.phase + white) * 0.5f; // LPF
val = white - c.phase; // HPF result
break;
}
} else if (c.type == GridCell::FORK) {
// Sum inputs from "Back" (Input direction)
// Rotation is "Forward". Input is "Back" (rot+2)
int inDir = (c.rotation + 2) % 4;
int dx=0, dy=0;
if(inDir==0) dy=-1; else if(inDir==1) dx=1; else if(inDir==2) dy=1; else dx=-1;
// We only read from the specific input neighbor
val = getInput(x, y, x+dx, y+dy);
} else if (c.type == GridCell::WIRE) {
// Sum inputs from all neighbors that point to me
float sum = 0.0f;
sum += getInput(x, y, x, y-1); // N
sum += getInput(x, y, x+1, y); // E
sum += getInput(x, y, x, y+1); // S
sum += getInput(x, y, x-1, y); // W
val = sum * c.param; // Fading
} else if (c.type == GridCell::DELAY) {
// Input is from the "Back" (rot+2)
int inDir = (c.rotation + 2) % 4;
int dx=0, dy=0;
if(inDir==0) dy=-1; else if(inDir==1) dx=1; else if(inDir==2) dy=1; else dx=-1;
float input_val = getInput(x, y, x+dx, y+dy);
if (c.buffer && c.buffer_size > 0) {
// Write current input to buffer
c.buffer[c.write_idx] = input_val;
// Calculate read index based on parameter. Max delay is buffer_size.
uint32_t delay_samples = c.param * (c.buffer_size - 1);
// Using modulo for wraparound. Need to handle negative result from subtraction.
int read_idx = (int)c.write_idx - (int)delay_samples;
if (read_idx < 0) {
read_idx += c.buffer_size;
}
// Read delayed value for output
val = c.buffer[read_idx];
// Increment write index
c.write_idx = (c.write_idx + 1) % c.buffer_size;
} else {
val = 0.0f; // No buffer, no output
}
} else if (c.type == GridCell::OPERATOR || c.type == GridCell::SINK) {
// Gather inputs
float inputs[4];
int count = 0;
float iN = getInput(x, y, x, y-1); if(iN!=0) inputs[count++] = iN;
float iE = getInput(x, y, x+1, y); if(iE!=0) inputs[count++] = iE;
float iS = getInput(x, y, x, y+1); if(iS!=0) inputs[count++] = iS;
float iW = getInput(x, y, x-1, y); if(iW!=0) inputs[count++] = iW;
if (c.type == GridCell::SINK) {
// Sink just sums everything
val = iN + iE + iS + iW;
} else {
// Operator
int opType = (int)(c.param * 5.99f);
if (count == 0) val = 0.0f;
else {
val = inputs[0];
for (int i=1; i<count; ++i) {
switch(opType) {
case 0: val += inputs[i]; break; // ADD
case 1: val *= inputs[i]; break; // MUL
case 2: val -= inputs[i]; break; // SUB
case 3: if(inputs[i]!=0) val /= inputs[i]; break; // DIV
case 4: if(inputs[i]<val) val = inputs[i]; break; // MIN
case 5: if(inputs[i]>val) val = inputs[i]; break; // MAX
}
}
}
}
}
next_values[x][y] = val;
}
}
// Update state
for(int x=0; x<5; ++x) {
for(int y=0; y<8; ++y) {
grid[x][y].value = next_values[x][y];
}
}
return grid[2][3].value;
}
void SynthEngine::process(int16_t* buffer, uint32_t numFrames) {
// Lock grid mutex to prevent UI from changing grid structure mid-process
std::lock_guard<std::mutex> lock(gridMutex);
for (uint32_t i = 0; i < numFrames; ++i) {
// The grid is now the primary sound source.
// The processGridStep() returns a float in the approx range of -1.0 to 1.0.
float sampleF = processGridStep();
// Soft clip grid sample to avoid harsh distortion before filtering.
if (sampleF > 1.0f) sampleF = 1.0f;
if (sampleF < -1.0f) sampleF = -1.0f;
// The filters were designed for a signal in the int16 range.
// We scale the grid's float output to match this expected range.
sampleF *= 32767.0f;
// Apply Filters (One-pole)
// Low Pass
_lpVal += _lpAlpha * (sampleF - _lpVal);
sampleF = _lpVal;
// High Pass (implemented as Input - LowPass(hp_cutoff))
_hpVal += _hpAlpha * (sampleF - _hpVal);
sampleF = sampleF - _hpVal;
@@ -143,7 +344,7 @@ void SynthEngine::process(int16_t* buffer, uint32_t numFrames) {
_envLevel = 0.0f;
break;
}
sampleF *= _envLevel;
// Apply Master Volume and write to buffer