"""
This example shows two things:
    
1) How to share memory from a PyoTableObject to a numpy array. Numpy 
   functions can be used to modify the table's content without copying
   every samples.

2) How to register a `callback` function that the server will call at
   the beginning of every processing loop (each `buffersize` samples).

"""
from pyo import *
import numpy as np

s = Server().boot()
bs = s.getBufferSize()

# Create a table of length `buffer size` and read it in loop.
t = DataTable(size=bs)
osc = TableRead(t, freq=t.getRate(), loop=True, mul=0.1).out()

# Share the table's memory with a numpy array.
arr = np.asarray(t.getBuffer())

def process():
    "Fill the array (so the table) with white noise."
    arr[:] = np.random.normal(0.0, 0.5, size=bs)

# Register the `process` function to be called at the beginning 
# of every processing loop.
s.setCallback(process)

s.gui(locals())