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class:: LoopBuf
summary:: sample looping oscillator
related:: Classes/PlayBuf
categories:: UGens>Buffer
Description::
Plays and loops between two frames of a sample resident in memory.
classmethods::
method::ar
argument::numChannels
number of channels that the buffer will be. this must be a fixed integer. The architecture of the SynthDef cannot change after it is compiled.
warning::
if you supply a bufnum of a buffer that has a different numChannels then you have specified to the LoopBuf, it will fail silently.
::
argument::bufnum
the index of the buffer to use
argument::rate
- 1.0 is normal, 2.0 is one octave up, 0.5 is one octave down. -1.0 is backwards normal rate ... etc.
argument::gate
positive gate starts playback from startPos. negative gate plays rest of sample from current position
argument::startPos
sample frame to start playback
argument::startLoop
sample frame of start of loop
argument::endLoop
sample frame of end of loop
argument::interpolation
1 means no interpolation, 2 is linear, 4 is cubic interpolation
Examples::
code::
// Create buffer and SynthDef
(
// read a whole sound into memory
b = Buffer.read(s,"sounds/a11wlk01.wav");
// make a simple sampler instrument
SynthDef("help-LoopBuf",{
arg out=0, bufnum=0, rate=1, glide=0, gate=1, loopRel=0, startPos=0, startLoop, endLoop, ipol=2;
var env, signal;
rate = Lag.kr(rate, glide);
env = EnvGen.ar(Env.adsr(0.1,0.2,1,2), gate, doneAction: 2);
signal = LoopBuf.ar(1,bufnum, BufRateScale.kr(bufnum) * rate, gate+loopRel, startPos, startLoop, endLoop, ipol);
Out.ar(out, (signal * env).dup);
}).send(s);
)
// start playback
s.sendMsg("/s_new", "help-LoopBuf", 3000, 1, 0, \bufnum, b.bufnum, \startLoop, 5000, \endLoop, 15000);
s.sendMsg("/n_set", 3000, \rate, -1); // backwards
s.sendMsg("/n_set", 3000, \rate, 1); // forwards
s.sendMsg("/n_set", 3000, \startLoop, 11000, \endLoop, 13000) // change loop points
s.sendMsg("/n_set", 3000, \glide, 5) // 5 second glide
s.sendMsg("/n_set", 3000, \rate, 2); // up an octave
s.sendMsg("/n_set", 3000, \rate, -1); // backwards again
s.sendMsg("/n_set", 3000, \rate, 1); // back to normal
s.sendMsg("/n_set", 3000, \ipol, 1); // no interpolation
s.sendMsg("/n_set", 3000, \ipol, 2); // linear interpolation
s.sendMsg("/n_set", 3000, \ipol, 4); // cubic interpolation
// release gate to hear post-loop
s.sendMsg("/n_set", 3000, \gate, 0);
// release instrument without post-loop
s.sendMsg("/s_new", "help-LoopBuf", 3000, 1, 0, \bufnum, b.bufnum, \startLoop, 11000, \endLoop, 13000);
s.sendMsg("/n_set", 3000, \loopRel, 1, \gate, 0);
::
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