Avoid taking the square-root of the ambient gain

Although it is more correct for preserving the apparent volume, the ambisonics-
based panning does not work on the same power scale, making it louder by
comparison.

7 files changed, 30 insertions, 61 deletions

diff --git a/Alc/ALu.c b/Alc/ALu.c
index 49ebd0c2..547a00a4 100644
--- a/Alc/ALu.c
+++ b/Alc/ALu.c
@@ -287,12 +287,12 @@ ALvoid CalcNonAttnSourceParams(ALvoice *voice, const ALsource *ALSource, const A
     ALfloat WetGain[MAX_SENDS];
     ALfloat WetGainHF[MAX_SENDS];
     ALfloat WetGainLF[MAX_SENDS];
-    ALint NumSends, Frequency;
+    ALuint NumSends, Frequency;
     const struct ChanMap *chans = NULL;
-    ALint num_channels = 0;
+    ALuint num_channels = 0;
     ALboolean DirectChannels;
     ALfloat Pitch;
-    ALint i, j, c;
+    ALuint i, j, c;
 
     /* Get device properties */
     NumSends  = Device->NumAuxSends;
@@ -464,7 +464,7 @@ ALvoid CalcNonAttnSourceParams(ALvoice *voice, const ALsource *ALSource, const A
                     Target[chans[c].channel] = DryGain;
                 ok = true;
             }
-            else for(i = 0;i < (ALint)Device->NumSpeakers;i++)
+            else for(i = 0;i < Device->NumSpeakers;i++)
             {
                 /* Attempt to match the input channel to an output based on its
                  * location. */
@@ -937,32 +937,21 @@ ALvoid CalcSourceParams(ALvoice *voice, const ALsource *ALSource, const ALCconte
     else
     {
         MixGains *gains = voice->Direct.Mix.Gains[0];
+        ALfloat Target[MaxChannels];
 
         /* Normalize the length, and compute panned gains. */
-        if(!(Distance > FLT_EPSILON))
-        {
-            ALfloat gain = 1.0f / sqrtf((float)Device->NumSpeakers);
-            for(j = 0;j < MaxChannels;j++)
-                gains[j].Target = 0.0f;
-            for(i = 0;i < (ALint)Device->NumSpeakers;i++)
-            {
-                enum Channel chan = Device->Speaker[i].ChanName;
-                gains[chan].Target = gain;
-            }
-        }
-        else
+        if(Distance > FLT_EPSILON)
         {
             ALfloat radius = ALSource->Radius;
-            ALfloat Target[MaxChannels];
             ALfloat invlen = 1.0f/maxf(Distance, radius);
             Position[0] *= invlen;
             Position[1] *= invlen;
             Position[2] *= invlen;
-
-            ComputeDirectionalGains(Device, Position, DryGain, Target);
-            for(j = 0;j < MaxChannels;j++)
-                gains[j].Target = Target[j];
         }
+        ComputeDirectionalGains(Device, Position, DryGain, Target);
+
+        for(j = 0;j < MaxChannels;j++)
+            gains[j].Target = Target[j];
         UpdateDryStepping(&voice->Direct, 1);
 
         voice->IsHrtf = AL_FALSE;
diff --git a/Alc/effects/autowah.c b/Alc/effects/autowah.c
index 09474d56..f4aaf49f 100644
--- a/Alc/effects/autowah.c
+++ b/Alc/effects/autowah.c
@@ -31,8 +31,8 @@
 /* Auto-wah is simply a low-pass filter with a cutoff frequency that shifts up
  * or down depending on the input signal, and a resonant peak at the cutoff.
  *
- * Currently, we assume a cutoff frequency range of 500hz (no amplitude) to
- * 3khz (peak gain). Peak gain is assumed to be in normalized scale.
+ * Currently, we assume a cutoff frequency range of 20hz (no amplitude) to
+ * 20khz (peak gain). Peak gain is assumed to be in normalized scale.
  */
 
 typedef struct ALautowahState {
@@ -76,7 +76,7 @@ static ALvoid ALautowahState_update(ALautowahState *state, ALCdevice *device, co
     state->PeakGain = slot->EffectProps.Autowah.PeakGain;
     state->Resonance = slot->EffectProps.Autowah.Resonance;
 
-    gain = sqrtf(1.0f / device->NumSpeakers) * slot->Gain;
+    gain = 1.0f/device->NumSpeakers * slot->Gain;
     SetGains(device, gain, state->Gain);
 }
 
diff --git a/Alc/effects/compressor.c b/Alc/effects/compressor.c
index 1c0054e7..9554a0f2 100644
--- a/Alc/effects/compressor.c
+++ b/Alc/effects/compressor.c
@@ -61,7 +61,7 @@ static ALvoid ALcompressorState_update(ALcompressorState *state, ALCdevice *Devi
 
     state->Enabled = Slot->EffectProps.Compressor.OnOff;
 
-    gain = sqrtf(1.0f / Device->NumSpeakers) * Slot->Gain;
+    gain = 1.0f/Device->NumSpeakers * Slot->Gain;
     SetGains(Device, gain, state->Gain);
 }
 
diff --git a/Alc/effects/distortion.c b/Alc/effects/distortion.c
index 04a05d99..9e36ea20 100644
--- a/Alc/effects/distortion.c
+++ b/Alc/effects/distortion.c
@@ -82,7 +82,7 @@ static ALvoid ALdistortionState_update(ALdistortionState *state, ALCdevice *Devi
     ALfilterState_setParams(&state->bandpass, ALfilterType_BandPass, 1.0f,
                             cutoff / (frequency*4.0f), bandwidth);
 
-    gain = sqrtf(1.0f / Device->NumSpeakers) * Slot->Gain;
+    gain = 1.0f/Device->NumSpeakers * Slot->Gain;
     SetGains(Device, gain, state->Gain);
 }
 
diff --git a/Alc/effects/equalizer.c b/Alc/effects/equalizer.c
index 5677426d..d04f36ee 100644
--- a/Alc/effects/equalizer.c
+++ b/Alc/effects/equalizer.c
@@ -93,7 +93,7 @@ static ALboolean ALequalizerState_deviceUpdate(ALequalizerState *UNUSED(state),
 static ALvoid ALequalizerState_update(ALequalizerState *state, ALCdevice *device, const ALeffectslot *slot)
 {
     ALfloat frequency = (ALfloat)device->Frequency;
-    ALfloat gain = sqrtf(1.0f / device->NumSpeakers) * slot->Gain;
+    ALfloat gain = 1.0f/device->NumSpeakers * slot->Gain;
 
     SetGains(device, gain, state->Gain);
 
diff --git a/Alc/effects/modulator.c b/Alc/effects/modulator.c
index 0665ad6c..e57040b3 100644
--- a/Alc/effects/modulator.c
+++ b/Alc/effects/modulator.c
@@ -149,7 +149,7 @@ static ALvoid ALmodulatorState_update(ALmodulatorState *state, ALCdevice *Device
     state->Filter.a[1] = -a;
     state->Filter.a[2] = 0.0f;
 
-    gain = sqrtf(1.0f/Device->NumSpeakers) * Slot->Gain;
+    gain = 1.0f/Device->NumSpeakers * Slot->Gain;
     SetGains(Device, gain, state->Gain);
 }
 
diff --git a/Alc/effects/reverb.c b/Alc/effects/reverb.c
index 8c17076a..45d25da7 100644
--- a/Alc/effects/reverb.c
+++ b/Alc/effects/reverb.c
@@ -1033,52 +1033,31 @@ static ALvoid Update3DPanning(const ALCdevice *Device, const ALfloat *Reflection
 {
     ALfloat earlyPan[3] = { ReflectionsPan[0], ReflectionsPan[1], ReflectionsPan[2] };
     ALfloat latePan[3] = { LateReverbPan[0], LateReverbPan[1], LateReverbPan[2] };
-    ALfloat earlyLen = 0.0f;
-    ALfloat lateLen = 0.0f;
     ALfloat length, invlen;
-    ALfloat ambientGain;
-    ALuint i;
-
-    Gain *= ReverbBoost;
-
-    /* Attenuate reverb according to its coverage (len=0 will give
-     * ambientGain, and len>=1 will be fully panned using Gain). */
-    ambientGain = minf(sqrtf(2.0f/Device->NumSpeakers), 1.0f) * Gain;
 
     length = earlyPan[0]*earlyPan[0] + earlyPan[1]*earlyPan[1] + earlyPan[2]*earlyPan[2];
-    if(length > FLT_EPSILON)
+    if(!(length > FLT_EPSILON))
+        earlyPan[0] = earlyPan[1] = earlyPan[2] = 0.0f;
+    else
     {
-        length = sqrtf(length);
-
-        invlen = 1.0f / length;
+        invlen = 1.0f / sqrtf(length);
         earlyPan[0] *= invlen;
         earlyPan[1] *= invlen;
         earlyPan[2] *= invlen;
-
-        earlyLen = minf(1.0f, length);
-        ComputeDirectionalGains(Device, earlyPan, Gain, State->Early.PanGain);
     }
+    ComputeDirectionalGains(Device, earlyPan, Gain, State->Early.PanGain);
 
     length = latePan[0]*latePan[0] + latePan[1]*latePan[1] + latePan[2]*latePan[2];
-    if(length > FLT_EPSILON)
+    if(!(length > FLT_EPSILON))
+        latePan[0] = latePan[1] = latePan[2] = 0.0f;
+    else
     {
-        length = sqrtf(length);
-
-        invlen = 1.0f / length;
+        invlen = 1.0f / sqrtf(length);
         latePan[0] *= invlen;
         latePan[1] *= invlen;
         latePan[2] *= invlen;
-
-        lateLen = minf(1.0f, length);
-        ComputeDirectionalGains(Device, latePan, Gain, State->Late.PanGain);
-    }
-
-    for(i = 0;i < Device->NumSpeakers;i++)
-    {
-        enum Channel chan = Device->Speaker[i].ChanName;
-        State->Early.PanGain[chan] = lerp(ambientGain, State->Early.PanGain[chan], earlyLen);
-        State->Late.PanGain[chan] = lerp(ambientGain, State->Late.PanGain[chan], lateLen);
     }
+    ComputeDirectionalGains(Device, latePan, Gain, State->Late.PanGain);
 }
 
 static ALvoid ALreverbState_update(ALreverbState *State, ALCdevice *Device, const ALeffectslot *Slot)
@@ -1163,12 +1142,13 @@ static ALvoid ALreverbState_update(ALreverbState *State, ALCdevice *Device, cons
 
         // Update early and late 3D panning.
         Update3DPanning(Device, Slot->EffectProps.Reverb.ReflectionsPan,
-                        Slot->EffectProps.Reverb.LateReverbPan, Slot->Gain, State);
+                        Slot->EffectProps.Reverb.LateReverbPan,
+                        Slot->Gain * ReverbBoost, State);
     }
     else
     {
         /* Update channel gains */
-        ALfloat gain = sqrtf(2.0f/Device->NumSpeakers) * ReverbBoost * Slot->Gain;
+        ALfloat gain = 2.0f/Device->NumSpeakers * Slot->Gain * ReverbBoost;
         SetGains(Device, gain, State->Gain);
     }
 }