import("stdfaust.lib");

// Maximum size of the delay buffer; a power of two because `fdelay` expects
// it so, as it allows for bit masking instead of modulus for index wrapping.
maxDelayLength = 1<<12;

// User parameters
grainLength = hslider("Grain Size (ms)", 100.0, 100.0, 30000.0, 1.0) : si.smooth(0.995);
grainPitch = hslider("Transpose (half-steps)", 0.0, -36.0, 36.0, 1.0) : si.smooth(0.995);

// Grain implementation.
grainFreq = ((2^(grainPitch / 12)) - 1) * (ma.SR / grainLength);
grainPhasor = os.phasor(4096, grainFreq);
maxGrainOffset = (grainLength * 1000 / ma.SR) : ba.latch(grainPhasor);
grainReadIndex = (grainPhasor * -1.0) : +(1.0) : *(maxGrainOffset);

// Hanning window on the range [0, 1].
win(x) = 0.5 * (1.0 - cos(x * 2 * ma.PI));

// process = de.fdelay(maxDelayLength, grainReadIndex) * win(grainPhasor);
process = de.sdelay(maxDelayLength, 1024, grainReadIndex) * win(grainPhasor);