Add a source radius property that determines the directionality of a sound

At 0 distance from the listener, the sound is omni-directional. As the source
and listener become 'radius' units apart, the sound becomes more directional.

With HRTF, an omni-directional sound is handled using 0-delay, pass-through
filter coefficients, which is blended with the real delay and coefficients as
needed to become more directional.

2 files changed, 4 insertions, 0 deletions

diff --git a/OpenAL32/Include/alSource.h b/OpenAL32/Include/alSource.h
index 6c6485ae..e362f096 100644
--- a/OpenAL32/Include/alSource.h
+++ b/OpenAL32/Include/alSource.h
@@ -71,6 +71,8 @@ typedef struct ALsource {
     volatile ALfloat RoomRolloffFactor;
     volatile ALfloat DopplerFactor;
 
+    volatile ALfloat Radius;
+
     enum Resampler Resampler;
 
     /**
diff --git a/OpenAL32/alSource.c b/OpenAL32/alSource.c
index 3da891bc..9f6c6a8b 100644
--- a/OpenAL32/alSource.c
+++ b/OpenAL32/alSource.c
@@ -2407,6 +2407,8 @@ static ALvoid InitSourceParams(ALsource *Source)
     Source->DopplerFactor = 1.0f;
     Source->DirectChannels = AL_FALSE;
 
+    Source->Radius = 0.0f;
+
     Source->DistanceModel = DefaultDistanceModel;
 
     Source->Resampler = DefaultResampler;