Update the B-Format HRTF coefficients to use the pseudo-inverse matrix

It's hard to tell which is ultimately better, although this way does make the
FOA output somewhat louder which will help when it's combined with direct HRTF
rendering.

1 files changed, 14 insertions, 26 deletions

diff --git a/Alc/hrtf.c b/Alc/hrtf.c
index b3b795ac..3249868d 100644
--- a/Alc/hrtf.c
+++ b/Alc/hrtf.c
@@ -158,23 +158,21 @@ ALuint BuildBFormatHrtf(const struct Hrtf *Hrtf, ALfloat (*coeffs)[HRIR_LENGTH][
         { DEG2RAD(-90.0f), DEG2RAD(   0.0f) },
     };
     static const ALfloat Ambi3DMatrix[14][2][MAX_AMBI_COEFFS] = {
-        { { 0.078851598f,  0.000000000f,  0.070561967f,  0.000000000f }, { 0.0714285714f,  0.0000000000f,  0.1237180798f,  0.0000000000f } },
-        { { 0.124051278f,  0.059847972f,  0.059847972f,  0.059847972f }, { 0.0714285714f,  0.0714285714f,  0.0714285714f,  0.0714285714f } },
-        { { 0.124051278f, -0.059847972f,  0.059847972f,  0.059847972f }, { 0.0714285714f, -0.0714285714f,  0.0714285714f,  0.0714285714f } },
-        { { 0.124051278f, -0.059847972f,  0.059847972f, -0.059847972f }, { 0.0714285714f, -0.0714285714f,  0.0714285714f, -0.0714285714f } },
-        { { 0.124051278f,  0.059847972f,  0.059847972f, -0.059847972f }, { 0.0714285714f,  0.0714285714f,  0.0714285714f, -0.0714285714f } },
-        { { 0.078851598f,  0.000000000f,  0.000000000f,  0.070561967f }, { 0.0714285714f,  0.0000000000f,  0.0000000000f,  0.1237180798f } },
-        { { 0.078851598f, -0.070561967f,  0.000000000f,  0.000000000f }, { 0.0714285714f, -0.1237180798f,  0.0000000000f,  0.0000000000f } },
-        { { 0.078851598f,  0.000000000f,  0.000000000f, -0.070561967f }, { 0.0714285714f,  0.0000000000f,  0.0000000000f, -0.1237180798f } },
-        { { 0.078851598f,  0.070561967f,  0.000000000f,  0.000000000f }, { 0.0714285714f,  0.1237180798f,  0.0000000000f,  0.0000000000f } },
-        { { 0.124051278f,  0.059847972f, -0.059847972f,  0.059847972f }, { 0.0714285714f,  0.0714285714f, -0.0714285714f,  0.0714285714f } },
-        { { 0.124051278f, -0.059847972f, -0.059847972f,  0.059847972f }, { 0.0714285714f, -0.0714285714f, -0.0714285714f,  0.0714285714f } },
-        { { 0.124051278f, -0.059847972f, -0.059847972f, -0.059847972f }, { 0.0714285714f, -0.0714285714f, -0.0714285714f, -0.0714285714f } },
-        { { 0.124051278f,  0.059847972f, -0.059847972f, -0.059847972f }, { 0.0714285714f,  0.0714285714f, -0.0714285714f, -0.0714285714f } },
-        { { 0.078851598f,  0.000000000f, -0.070561967f,  0.000000000f }, { 0.0714285714f,  0.0000000000f, -0.1237180798f,  0.0000000000f } },
+        { { 0.1889822365f,  0.0000000000f,  0.1889822365f,  0.0000000000f }, { 0.0714285714f,  0.0000000000f,  0.1237180798f,  0.0000000000f } },
+        { { 0.1889822365f,  0.1091089451f,  0.1091089451f,  0.1091089451f }, { 0.0714285714f,  0.0714285714f,  0.0714285714f,  0.0714285714f } },
+        { { 0.1889822365f, -0.1091089451f,  0.1091089451f,  0.1091089451f }, { 0.0714285714f, -0.0714285714f,  0.0714285714f,  0.0714285714f } },
+        { { 0.1889822365f, -0.1091089451f,  0.1091089451f, -0.1091089451f }, { 0.0714285714f, -0.0714285714f,  0.0714285714f, -0.0714285714f } },
+        { { 0.1889822365f,  0.1091089451f,  0.1091089451f, -0.1091089451f }, { 0.0714285714f,  0.0714285714f,  0.0714285714f, -0.0714285714f } },
+        { { 0.1889822365f,  0.0000000000f,  0.0000000000f,  0.1889822365f }, { 0.0714285714f,  0.0000000000f,  0.0000000000f,  0.1237180798f } },
+        { { 0.1889822365f, -0.1889822365f,  0.0000000000f,  0.0000000000f }, { 0.0714285714f, -0.1237180798f,  0.0000000000f,  0.0000000000f } },
+        { { 0.1889822365f,  0.0000000000f,  0.0000000000f, -0.1889822365f }, { 0.0714285714f,  0.0000000000f,  0.0000000000f, -0.1237180798f } },
+        { { 0.1889822365f,  0.1889822365f,  0.0000000000f,  0.0000000000f }, { 0.0714285714f,  0.1237180798f,  0.0000000000f,  0.0000000000f } },
+        { { 0.1889822365f,  0.1091089451f, -0.1091089451f,  0.1091089451f }, { 0.0714285714f,  0.0714285714f, -0.0714285714f,  0.0714285714f } },
+        { { 0.1889822365f, -0.1091089451f, -0.1091089451f,  0.1091089451f }, { 0.0714285714f, -0.0714285714f, -0.0714285714f,  0.0714285714f } },
+        { { 0.1889822365f, -0.1091089451f, -0.1091089451f, -0.1091089451f }, { 0.0714285714f, -0.0714285714f, -0.0714285714f, -0.0714285714f } },
+        { { 0.1889822365f,  0.1091089451f, -0.1091089451f, -0.1091089451f }, { 0.0714285714f,  0.0714285714f, -0.0714285714f, -0.0714285714f } },
+        { { 0.1889822365f,  0.0000000000f, -0.1889822365f,  0.0000000000f }, { 0.0714285714f,  0.0000000000f, -0.1237180798f,  0.0000000000f } },
     };
-#define AMBIHF_GAIN 1.0f
-#define AMBILF_GAIN 0.553914423f /* -5.13dB */
 
 /* Change this to 2 for dual-band HRTF processing. May require a higher quality
  * band-splitter, or better calculation of the new IR length to deal with the
@@ -236,11 +234,6 @@ ALuint BuildBFormatHrtf(const struct Hrtf *Hrtf, ALfloat (*coeffs)[HRIR_LENGTH][
             for(i = 0;i < Hrtf->irSize;i++)
                 temps[2][i] = fir[i] / 32767.0f;
             bandsplit_process(&splitter, temps[0], temps[1], temps[2], HRIR_LENGTH);
-            /* Scale the low and high frequency responses. */
-            for(i = 0;i < HRIR_LENGTH;i++)
-                temps[0][i] *= AMBIHF_GAIN;
-            for(i = 0;i < HRIR_LENGTH;i++)
-                temps[1][i] *= AMBILF_GAIN;
         }
 
         /* Add to the left output coefficients with the specified delay. */
@@ -270,11 +263,6 @@ ALuint BuildBFormatHrtf(const struct Hrtf *Hrtf, ALfloat (*coeffs)[HRIR_LENGTH][
             for(i = 0;i < Hrtf->irSize;i++)
                 temps[2][i] = fir[i] / 32767.0f;
             bandsplit_process(&splitter, temps[0], temps[1], temps[2], HRIR_LENGTH);
-            /* Scale the low and high frequency responses. */
-            for(i = 0;i < HRIR_LENGTH;i++)
-                temps[0][i] *= AMBIHF_GAIN;
-            for(i = 0;i < HRIR_LENGTH;i++)
-                temps[1][i] *= AMBILF_GAIN;
         }
 
         /* Add to the right output coefficients with the specified delay. */