In this way we have to store the Synths in SuperCollider server and use the openFrameworks application as an interpreter.
Store SynthDefs in SuperCollider
SynthDef(\playbuf_1, { |bufnum = 0, outbus = 0, amp = 0.5, loop = 0, pan = 0, rate = 1.0|
var data;
data = PlayBuf.ar(1, bufnum, BufRateScale.kr(bufnum) * rate, 0, 0, loop);
FreeSelfWhenDone.kr(data);
Out.ar(outbus, Pan2.ar(data, pan, amp));
}).store;