/**
 @defgroup SpatialAudio Spatial Audio
*/
/**
 @defgroup AmbisonicsConventions Ambisonics Conventions
 @ingroup SpatialAudio

 Processings on the spatialization plugin follow the ambisonics conventions.
 
 @section AmbisonicsCoordinateSystem Cartesian coordinate system

 When coordinates are centered in the listener:
 - X axis positive goes front
 - Y axis positive goes left
 - Z axis positive goes up

 When other coordinate frame is defined, also the right hand rule applies.

 Points relative to the listener can be expressed by providing relative
 polar coordinates: Azimuth, elevation and distance:

 - \b Azimuth is the angle of the projection of the point on the X-Y plane
   having the 0 at the front of the listener and increasing when rotating
   to the left.
   - Valid values for the Azimuth are 0 to 360.
     Angles outside those ranges are not accepted.
 - \b Elevation is the angle to the horizon, positive going up, negative going down.
   - Elevations range from -90 to 90.
     Angles outside those ranges are not accepted.

 Further specifications:
 - Azimuth and elevations angles outside those ranges are not accepted.
 - Angles are expressed in degrees unless otherwise specified.
 - Distances and Cartesian coordinates are expressed in meters unless otherwise specified.

 @section AmbisonicsPhisicalMeasurements Physical measurements

 @todo providing links to the wikipedia on acoustic pressure and velocity
 @todo explaining signs and directions for physical measurements of pressure and velocity for plane waves coming from different points

 @section AmbisonicsEncoding Ambisonics encoding

 Given physical measurements of the pressure and velocity,
 B-format components, W, X, Y and Z, are composed in the following way:

 @f{eqnarray*}
  W = \frac 1 {\sqrt{2}} p \\
  X = - v_x \\
  Y = - v_y \\
  Z = - v_z
 @f}

*/