class:: GrainFM
summary:: Granular synthesis with frequency modulated sine tones
categories:: UGens>Generators>Granular
related:: Classes/GrainIn, Classes/GrainSin, Classes/GrainBuf

classmethods::
private:: categories

method:: ar

argument:: numChannels
the number of channels to output. If 1, mono is returned and pan is ignored.

argument:: trigger
a kr or ar trigger to start a new grain. If ar, grains after the start of the synth are sample accurate.

argument:: dur
size of the grain (in seconds).

argument:: carfreq
the carrier freq of the grain generators internal oscillator

argument:: modfreq
the modulating freq of the grain generators internal oscillator

argument:: index
the index of modulation

argument:: pan
determines where to pan the output.
list::
## If numChannels = 1, no panning is done.
## If numChannels = 2, panning is similar to Pan2.
## If numChannels > 2, pannins is the same as PanAz.
::

argument:: envbufnum
the buffer number containing a signal to use for the grain envelope. -1 uses a built-in Hann envelope.

argument:: maxGrains
the maximum number of overlapping grains that can be used at a given time. This value is set at the UGens init time and can't be modified. Defaults to 512. This can be set lower for more efficient use of memory.

warning:: The above parameter is new (post SC 3.3.1) and has the potential to break code written <= 3.3.1. This parameter is BEFORE the mul slot, and you may need to update code to account for this difference. ::

argument:: mul

argument:: add

discussion:: All args except numChannels and trigger are polled at grain creation time.
instancemethods::
private:: init, argNamesInputsOffset

examples::
code::
s.boot;

(
var winenv;
// a custom envelope
winenv = Env([0, 1, 0], [0.5, 0.5], [8, -8]);
z = Buffer.sendCollection(s, winenv.discretize, 1);

SynthDef(\fm_grain_test, {arg gate = 1, amp = 1, envbuf;
	var pan, env, freqdev;
	// use mouse x to control panning
	pan = MouseX.kr(-1, 1);
	// use WhiteNoise and mouse y to control deviation from center pitch
	freqdev = WhiteNoise.kr(MouseY.kr(0, 400));
	env = EnvGen.kr(
		Env([0, 1, 0], [1, 1], \sin, 1),
		gate,
		levelScale: amp,
		doneAction: Done.freeSelf);
	Out.ar(0,
		GrainFM.ar(2, Impulse.kr(10), 0.1, 440 + freqdev, 200, LFNoise1.kr.range(1, 10),
			pan, envbuf) * env)
	}).add;

)

// use built-in env
x = Synth(\fm_grain_test, [\envbuf, -1])

// switch to the custom env
x.set(\envbuf, z)
x.set(\envbuf, -1);

x.set(\gate, 0);
::