..
  This file was automatically converted from MediaWiki syntax.
  If some markup is wrong, looks weird or doesn't make sense, feel free
  to fix it.

  Please remove this comment once this file was manually checked
  and no "strange ReST" artifacts remain.

.. _dsp-effects:

DSP Effects
===========

DSP, or Digital Signal Processing, allows you to apply effect filters to your
ingame audio. As of now, DSP effects are only available in Panda if you use
the FMOD audio library. By default, Panda ships using the OpenAL audio library
but FMOD can be enabled simply by editing
:ref:`Config.prc <configuring-panda>`. Please keep in mind that using FMOD in
a commercial application will require purchasing a license.

You will need to change this line in your Config.prc: (some versions of Panda
might already be set to FMOD)

::
    
    audio-library-name p3openal_audio



To this:

::
    
    audio-library-name p3fmod_audio



The FilterProperties Object
===========================


Any DSP you add to your sound will require the use of "FilterProperties",
which is a list of filters and their coefficients. Start with this import:



.. code-block:: python
    
    from panda3d.core import FilterProperties



This will allow you to create lists of filters, like this one:



.. code-block:: python
    
    fp = FilterProperties()



This just adds a blank filter list. From here we can add whatever filter we'd
like. To stay consistent with the example below, we'll add a reverb effect.



.. code-block:: python
    
    fp.addReverb(0.6, 0.5, 0.1, 0.1, 0.1)



All this really does is add this particular reverb to our filter list - sound
is not yet affected. To apply these filters to our audio output, use:



.. code-block:: python
    
    audioMgr.configureFilters(fp)



where ``audioMgr`` is an
``AudioManager`` object, most likely
``base.sfxManagerList[0]`` or
``base.musicManager``.

Depending on the sound you use, reverb may be very or only slightly
noticeable; try using a quick sound at first, like a clap.

You can add more than just reverb to your sound. The full list of available
filters is here:

http://panda3d.org/apiref.php?page=FilterProperties

Below is a sample program for adding a reverb effect:



.. code-block:: python
    
    # This is just to ensure that we are using FMOD. In your application,
    # please edit the Config.prc file that you distribute
    from panda3d.core import loadPrcFileData
    loadPrcFileData("", "audio-library-name p3fmod_audio")
    
    import direct.directbase.DirectStart
    from panda3d.core import FilterProperties
    
    mySound = loader.loadSfx("models/audio/sfx/GUI_rollover.wav")
    mySound.setLoop(True)
    mySound.play()
    
    fp = FilterProperties()
    fp.addReverb(0.6, 0.5, 0.1, 0.1, 0.1)
    base.sfxManagerList[0].configureFilters(fp)
    
    run()