From 98d78f7ff9a3636567273e4384731debca2ec79f Mon Sep 17 00:00:00 2001
From: Chris Robinson <chris.kcat@gmail.com>
Date: Fri, 26 Nov 2010 00:24:54 -0800
Subject: Slightly improve channel gain calculations

---
 Alc/ALu.c       |  4 ++--
 Alc/alcReverb.c | 13 ++++++-------
 2 files changed, 8 insertions(+), 9 deletions(-)

diff --git a/Alc/ALu.c b/Alc/ALu.c
index 78f18782..b7471132 100644
--- a/Alc/ALu.c
+++ b/Alc/ALu.c
@@ -620,13 +620,13 @@ ALvoid CalcSourceParams(ALsource *ALSource, const ALCcontext *ALContext)
     DirGain = aluSqrt(Position[0]*Position[0] + Position[2]*Position[2]);
     // elevation adjustment for directional gain. this sucks, but
     // has low complexity
-    AmbientGain = 1.0/aluSqrt(Device->NumChan) * (1.0-DirGain);
+    AmbientGain = aluSqrt(1.0/Device->NumChan);
     for(s = 0;s < OUTPUTCHANNELS;s++)
         ALSource->Params.DryGains[s] = 0.0f;
     for(s = 0;s < (ALsizei)Device->NumChan;s++)
     {
         Channel chan = Device->Speaker2Chan[s];
-        ALfloat gain = SpeakerGain[chan]*DirGain + AmbientGain;
+        ALfloat gain = AmbientGain + (SpeakerGain[chan]-AmbientGain)*DirGain;
         ALSource->Params.DryGains[chan] = DryGain * gain;
     }
 
diff --git a/Alc/alcReverb.c b/Alc/alcReverb.c
index e1f6df45..02f07f9a 100644
--- a/Alc/alcReverb.c
+++ b/Alc/alcReverb.c
@@ -596,7 +596,7 @@ static ALvoid Update3DPanning(const ALCdevice *Device, const ALfloat *Reflection
     ALfloat latePan[3] = { LateReverbPan[0], LateReverbPan[1],
                            LateReverbPan[2] };
     const ALfloat *speakerGain;
-    ALfloat dirGain, ambientGain;
+    ALfloat dirGain;
     ALfloat length;
     ALuint index;
     ALint pos;
@@ -629,27 +629,26 @@ static ALvoid Update3DPanning(const ALCdevice *Device, const ALfloat *Reflection
     pos = aluCart2LUTpos(earlyPan[2], earlyPan[0]);
     speakerGain = &Device->PanningLUT[OUTPUTCHANNELS * pos];
     dirGain = aluSqrt((earlyPan[0] * earlyPan[0]) + (earlyPan[2] * earlyPan[2]));
-    ambientGain = (1.0 - dirGain);
+
     for(index = 0;index < OUTPUTCHANNELS;index++)
         State->Early.PanGain[index] = 0.0f;
     for(index = 0;index < Device->NumChan;index++)
     {
         Channel chan = Device->Speaker2Chan[index];
-        State->Early.PanGain[chan] = speakerGain[chan]*dirGain +
-                                     ambientGain;
+        State->Early.PanGain[chan] = 1.0 + (speakerGain[chan]-1.0)*dirGain;
     }
 
+
     pos = aluCart2LUTpos(latePan[2], latePan[0]);
     speakerGain = &Device->PanningLUT[OUTPUTCHANNELS * pos];
     dirGain = aluSqrt((latePan[0] * latePan[0]) + (latePan[2] * latePan[2]));
-    ambientGain = (1.0 - dirGain);
+
     for(index = 0;index < OUTPUTCHANNELS;index++)
          State->Late.PanGain[index] = 0.0f;
     for(index = 0;index < Device->NumChan;index++)
     {
         Channel chan = Device->Speaker2Chan[index];
-        State->Late.PanGain[chan] = speakerGain[chan]*dirGain +
-                                    ambientGain;
+        State->Late.PanGain[chan] = 1.0 + (speakerGain[chan]-1.0)*dirGain;
     }
 }
 
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