Simple Audio
============

Here you can learn how to make a simple Pure Data audio patch with ``pdpy``. 

This patch sends out a sinusoid at 440 ``osc~ 440``, 
with amplitude 0.01 ``*~ 0.01``, 
to channels #1, #3 and #4 of the system audio ``dac~ 1 2 3 4``


.. code-block:: python
  :linenos:
  
  from pdpy_lib import PdPy, Obj                      # necesary imports
  mypatch = PdPy(name="simpleaudio", root=True)   # initialize
  obj1 = Obj('osc~').addargs(440)                 # an ``osc~`` at 440 Hz
  obj2 = Obj('*~').addargs(0.01)                  # a signal multiplier at 0.01
  obj3 = Obj('dac~').addargs([1, 2, 3, 4])        # a 4-channel ``dac~``
  mypatch.create(obj1, obj2, obj3)                # create them in the patch
  mypatch.connect(obj1, obj2)                     # connect ``osc~`` to ``*~``
  mypatch.connect(obj2, [obj3, 0, 2, 3])          # connect ``*~`` chans 1,3,4
  mypatch.write()                                 # write out the patch
  

The logic of lines 1-6 and 8 is similar to :doc:`holamundo`. 
Please refer to that example for an overview. 
The thing to notice here is the connections in lines 7 and 8.


Connections
-----------

Here we see how to make connections. 
Go to :doc:`connections` for more information.

In line 7, the ``connect`` method is called with ``obj1`` and ``obj2``::
  
  mypatch.connect(obj1, obj2)


This means that the first outlet of the first object is connected to the first inlet of the second object. 
So, the first and only outlet of ``osc~ 440`` is connected to the first inlet of the multiplier ``*~ 0.01``.

Notice we have a different syntax on line 8::
  
  mypatch.connect(obj2, [obj3, 0, 2, 3])


Here, we connect the first outlet of the first object, 
with the 1st, 3rd, and 4th inlets of the second object.
So, the first outlet of the multiplier ``*~ 0.01`` fans out to
the ``dac~ 1 2 3 4``, specifically, inlets #1, #3, and #4. 


.. note::
  
  When a list is passed to ``mypatch.connect`` the inlet indices start at 0. 
  So, the first inlet is the 0th, the second is the 1st, and so on.


.. note::
  
  The order does not matter, so we can get the same result calling::

    mypatch.connect(obj2, [obj3, 3, 0, 2])