[Openal-devel] Cone Angle 180 or 360 (Win32)

[rage2050]

Using OpenAL32.dll Generic Software Device (DirectSound),
I'm confused about cone angle.

In function aluCalculateSourceParameters(), the Angle between
Source and Listener is calculated as follows;
  Angle=(ALfloat)(180.0*acos(aluDotproduct(Direction,SourceToListener))/3.141592654f);

I think,

(1) When Source and Listener are at the same position,
  DotProduct=0, acos(0)=pi/2, so Angle=90.
  I think if SoucePosition==ListenerPosition, it is better 
  treated as Angle=0.

(2) Angle ranges 0 (front) to 180 (back). OpenAL spec defines 
  AL_CONE_(INNER|OUTER)_ANGLE==360.0f is omni-directional source.
  Suppose we like to set GAIN=1.0f right in front of the Source,
  and GAIN=0.1f right behind. 
  We should set AL_CONE_INNER_ANGLE=0.0f, AL_CONE_OUTER_GAIN=0.1f.
  Then, how about AL_CONE_OUTER_ANGLE?
  Current implementation requires AL_CONE_OUTER_ANGLE=180.0f;
  but I think AL_CONE_OUTER_ANGLE=360.0f; is more natural,
  because OpenAL spec defines "360" is omni-directional.

How do you think about these?

Thanks.

#if 0
  Sorry for my bad Engrish.
#endif

/** @name  rage2050
    @email rage2050 at mail.goo.ne.jp
    @url   http://hp.vector.co.jp/authors/VA024832/
*/