From aed35fd811f7aa5f1a9d2edb499e43d490ede96e Mon Sep 17 00:00:00 2001
From: Chris Robinson <chris.kcat@gmail.com>
Date: Sun, 29 Apr 2012 05:04:46 -0700
Subject: [PATCH] Use ComputeAngleGains for multi-channel sources and remove
 the unused lookup table stuff

---
 Alc/ALu.c                 | 14 ++--------
 Alc/panning.c             | 70 +----------------------------------------------
 OpenAL32/Include/alMain.h |  1 -
 OpenAL32/Include/alu.h    |  4 ---
 4 files changed, 4 insertions(+), 85 deletions(-)

diff --git a/Alc/ALu.c b/Alc/ALu.c
index 915c06e9..2777b0fe 100644
--- a/Alc/ALu.c
+++ b/Alc/ALu.c
@@ -115,14 +115,12 @@ ALvoid CalcNonAttnSourceParams(ALsource *ALSource, const ALCcontext *ALContext)
     ALfloat WetGain[MAX_SENDS];
     ALfloat WetGainHF[MAX_SENDS];
     ALint NumSends, Frequency;
-    const ALfloat *ChannelGain;
     const struct ChanMap *chans = NULL;
     enum Resampler Resampler;
     ALint num_channels = 0;
     ALboolean DirectChannels;
     ALfloat Pitch;
     ALfloat cw;
-    ALuint pos;
     ALint i, c;
 
     /* Get device properties */
@@ -281,17 +279,11 @@ ALvoid CalcNonAttnSourceParams(ALsource *ALSource, const ALCcontext *ALContext)
             /* Special-case LFE */
             if(chans[c].channel == LFE)
             {
-                SrcMatrix[c][LFE] += DryGain;
+                SrcMatrix[c][chans[c].channel] = DryGain;
                 continue;
             }
-            pos = aluCart2LUTpos(aluSin(chans[c].angle), aluCos(chans[c].angle));
-            ChannelGain = Device->PanningLUT[pos];
-
-            for(i = 0;i < (ALint)Device->NumChan;i++)
-            {
-                enum Channel chan = Device->Speaker2Chan[i];
-                SrcMatrix[c][chan] += DryGain * ChannelGain[chan];
-            }
+            ComputeAngleGains(Device, chans[c].angle, 0.0f, DryGain,
+                              SrcMatrix[c]);
         }
     }
     for(i = 0;i < NumSends;i++)
diff --git a/Alc/panning.c b/Alc/panning.c
index 288f44d1..d6d4bc21 100644
--- a/Alc/panning.c
+++ b/Alc/panning.c
@@ -139,30 +139,6 @@ static void SetSpeakerArrangement(const char *name, ALfloat SpeakerAngle[MAXCHAN
     }
 }
 
-static ALfloat aluLUTpos2Angle(ALint pos)
-{
-    if(pos < QUADRANT_NUM)
-        return aluAtan((ALfloat)pos / (ALfloat)(QUADRANT_NUM - pos));
-    if(pos < 2 * QUADRANT_NUM)
-        return F_PI_2 + aluAtan((ALfloat)(pos - QUADRANT_NUM) / (ALfloat)(2 * QUADRANT_NUM - pos));
-    if(pos < 3 * QUADRANT_NUM)
-        return aluAtan((ALfloat)(pos - 2 * QUADRANT_NUM) / (ALfloat)(3 * QUADRANT_NUM - pos)) - F_PI;
-    return aluAtan((ALfloat)(pos - 3 * QUADRANT_NUM) / (ALfloat)(4 * QUADRANT_NUM - pos)) - F_PI_2;
-}
-
-ALint aluCart2LUTpos(ALfloat im, ALfloat re)
-{
-    ALint pos = 0;
-    ALfloat denom = aluFabs(im) + aluFabs(re);
-    if(denom > 0.0f)
-        pos = (ALint)(QUADRANT_NUM*aluFabs(im) / denom + 0.5);
-
-    if(re < 0.0f)
-        pos = 2 * QUADRANT_NUM - pos;
-    if(im < 0.0f)
-        pos = LUT_NUM - pos;
-    return pos%LUT_NUM;
-}
 
 /**
  * ComputeAngleGains
@@ -357,14 +333,12 @@ ALvoid ComputeAngleGains(const ALCdevice *device, ALfloat angle, ALfloat hwidth,
     }
 }
 
+
 ALvoid aluInitPanning(ALCdevice *Device)
 {
     const char *layoutname = NULL;
     enum Channel *Speaker2Chan;
     ALfloat *SpeakerAngle;
-    ALfloat Alpha, Theta;
-    ALint pos;
-    ALuint s;
 
     Speaker2Chan = Device->Speaker2Chan;
     SpeakerAngle = Device->SpeakerAngle;
@@ -467,46 +441,4 @@ ALvoid aluInitPanning(ALCdevice *Device)
     }
     if(layoutname && Device->Type != Loopback)
         SetSpeakerArrangement(layoutname, SpeakerAngle, Speaker2Chan, Device->NumChan);
-
-    for(pos = 0; pos < LUT_NUM; pos++)
-    {
-        ALfloat *PanningLUT = Device->PanningLUT[pos];
-
-        /* clear all values */
-        for(s = 0; s < MAXCHANNELS; s++)
-            PanningLUT[s] = 0.0f;
-
-        if(Device->NumChan == 1)
-        {
-            PanningLUT[Speaker2Chan[0]] = 1.0f;
-            continue;
-        }
-
-        /* source angle */
-        Theta = aluLUTpos2Angle(pos);
-
-        /* set panning values */
-        for(s = 0; s < Device->NumChan - 1; s++)
-        {
-            if(Theta >= SpeakerAngle[s] && Theta < SpeakerAngle[s+1])
-            {
-                /* source between speaker s and speaker s+1 */
-                Alpha = (Theta-SpeakerAngle[s]) /
-                        (SpeakerAngle[s+1]-SpeakerAngle[s]);
-                PanningLUT[Speaker2Chan[s]]   = aluSqrt(1.0f-Alpha);
-                PanningLUT[Speaker2Chan[s+1]] = aluSqrt(     Alpha);
-                break;
-            }
-        }
-        if(s == Device->NumChan - 1)
-        {
-            /* source between last and first speaker */
-            if(Theta < SpeakerAngle[0])
-                Theta += F_PI*2.0f;
-            Alpha = (Theta-SpeakerAngle[s]) /
-                    (F_PI*2.0f + SpeakerAngle[0]-SpeakerAngle[s]);
-            PanningLUT[Speaker2Chan[s]] = aluSqrt(1.0f-Alpha);
-            PanningLUT[Speaker2Chan[0]] = aluSqrt(     Alpha);
-        }
-    }
 }
diff --git a/OpenAL32/Include/alMain.h b/OpenAL32/Include/alMain.h
index 54fbcdf5..76a0bfbc 100644
--- a/OpenAL32/Include/alMain.h
+++ b/OpenAL32/Include/alMain.h
@@ -579,7 +579,6 @@ struct ALCdevice_struct
 
     enum Channel Speaker2Chan[MAXCHANNELS];
     ALfloat SpeakerAngle[MAXCHANNELS];
-    ALfloat PanningLUT[LUT_NUM][MAXCHANNELS];
     ALuint  NumChan;
 
     ALfloat ClickRemoval[MAXCHANNELS];
diff --git a/OpenAL32/Include/alu.h b/OpenAL32/Include/alu.h
index ff5601e5..ccc18746 100644
--- a/OpenAL32/Include/alu.h
+++ b/OpenAL32/Include/alu.h
@@ -110,9 +110,6 @@ _CRTIMP unsigned int __cdecl __MINGW_NOTHROW _controlfp (unsigned int unNew, uns
 #define aluFloor(x) ((ALfloat)floor((double)(x)))
 #endif
 
-#define QUADRANT_NUM  128
-#define LUT_NUM       (4 * QUADRANT_NUM)
-
 #ifdef __cplusplus
 extern "C" {
 #endif
@@ -296,7 +293,6 @@ static __inline void aluNormalize(ALfloat *inVector)
 
 
 ALvoid aluInitPanning(ALCdevice *Device);
-ALint aluCart2LUTpos(ALfloat im, ALfloat re);
 
 ALvoid ComputeAngleGains(const ALCdevice *device, ALfloat angle, ALfloat hwidth, ALfloat ingain, ALfloat *gains);
 
-- 
2.11.4.GIT