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Use a few more HRIRs for the HRTF B-Format decoder

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14 in total, an 8-point cube and a 6-point diamond shape, to help improve sound
localization a bit. Incurs no real extra CPU cost once the IRs are built.
This commit is contained in:
Chris Robinson
2016-09-07 16:26:13 -07:00
parent a52cfc8048
commit 742f181595
1 changed files with 31 additions and 19 deletions
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Alc/hrtf.c
+31 -19
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@@ -178,25 +178,37 @@ ALuint BuildBFormatHrtf(const struct Hrtf *Hrtf, ALfloat (*coeffs)[HRIR_LENGTH][
static const struct {
ALfloat elevation;
ALfloat azimuth;
} CubePoints[8] = {
} Ambi3DPoints[14] = {
{ DEG2RAD( 90.0f), DEG2RAD( 0.0f) },
{ DEG2RAD( 35.0f), DEG2RAD( -45.0f) },
{ DEG2RAD( 35.0f), DEG2RAD( 45.0f) },
{ DEG2RAD( 35.0f), DEG2RAD(-135.0f) },
{ DEG2RAD( 35.0f), DEG2RAD( 135.0f) },
{ DEG2RAD( 35.0f), DEG2RAD(-135.0f) },
{ DEG2RAD( 0.0f), DEG2RAD( 0.0f) },
{ DEG2RAD( 0.0f), DEG2RAD( 90.0f) },
{ DEG2RAD( 0.0f), DEG2RAD( 180.0f) },
{ DEG2RAD( 0.0f), DEG2RAD( -90.0f) },
{ DEG2RAD(-35.0f), DEG2RAD( -45.0f) },
{ DEG2RAD(-35.0f), DEG2RAD( 45.0f) },
{ DEG2RAD(-35.0f), DEG2RAD(-135.0f) },
{ DEG2RAD(-35.0f), DEG2RAD( 135.0f) },
{ DEG2RAD(-35.0f), DEG2RAD(-135.0f) },
{ DEG2RAD(-90.0f), DEG2RAD( 0.0f) },
};
static const ALfloat CubeMatrix[8][2][MAX_AMBI_COEFFS] = {
{ { 0.25f, 0.1443375672f, 0.1443375672f, 0.1443375672f }, { 0.125f, 0.125f, 0.125f, 0.125f } },
{ { 0.25f, -0.1443375672f, 0.1443375672f, 0.1443375672f }, { 0.125f, -0.125f, 0.125f, 0.125f } },
{ { 0.25f, 0.1443375672f, 0.1443375672f, -0.1443375672f }, { 0.125f, 0.125f, 0.125f, -0.125f } },
{ { 0.25f, -0.1443375672f, 0.1443375672f, -0.1443375672f }, { 0.125f, -0.125f, 0.125f, -0.125f } },
{ { 0.25f, 0.1443375672f, -0.1443375672f, 0.1443375672f }, { 0.125f, 0.125f, -0.125f, 0.125f } },
{ { 0.25f, -0.1443375672f, -0.1443375672f, 0.1443375672f }, { 0.125f, -0.125f, -0.125f, 0.125f } },
{ { 0.25f, 0.1443375672f, -0.1443375672f, -0.1443375672f }, { 0.125f, 0.125f, -0.125f, -0.125f } },
{ { 0.25f, -0.1443375672f, -0.1443375672f, -0.1443375672f }, { 0.125f, -0.125f, -0.125f, -0.125f } },
static const ALfloat Ambi3DMatrix[14][2][MAX_AMBI_COEFFS] = {
{ { 0.18898176f, 0.000000000f, 0.188982460f, 0.000000000f }, { 0.0714283915f, 0.0000000000f, 0.1237180798f, 0.0000000000f } },
{ { 0.18898176f, 0.109109004f, 0.109109004f, 0.109109004f }, { 0.0714283915f, 0.0714286206f, 0.0714286206f, 0.0714286206f } },
{ { 0.18898176f, -0.109109004f, 0.109109004f, 0.109109004f }, { 0.0714283915f, -0.0714286206f, 0.0714286206f, 0.0714286206f } },
{ { 0.18898176f, -0.109109004f, 0.109109004f, -0.109109004f }, { 0.0714283915f, -0.0714286206f, 0.0714286206f, -0.0714286206f } },
{ { 0.18898176f, 0.109109004f, 0.109109004f, -0.109109004f }, { 0.0714283915f, 0.0714286206f, 0.0714286206f, -0.0714286206f } },
{ { 0.18898176f, 0.000000000f, 0.000000000f, 0.188982460f }, { 0.0714283915f, 0.0000000000f, 0.0000000000f, 0.1237180798f } },
{ { 0.18898176f, -0.188982460f, 0.000000000f, 0.000000000f }, { 0.0714283915f, -0.1237180798f, 0.0000000000f, 0.0000000000f } },
{ { 0.18898176f, 0.000000000f, 0.000000000f, -0.188982460f }, { 0.0714283915f, 0.0000000000f, 0.0000000000f, -0.1237180798f } },
{ { 0.18898176f, 0.188982460f, 0.000000000f, 0.000000000f }, { 0.0714283915f, 0.1237180798f, 0.0000000000f, 0.0000000000f } },
{ { 0.18898176f, 0.109109004f, -0.109109004f, 0.109109004f }, { 0.0714283915f, 0.0714286206f, -0.0714286206f, 0.0714286206f } },
{ { 0.18898176f, -0.109109004f, -0.109109004f, 0.109109004f }, { 0.0714283915f, -0.0714286206f, -0.0714286206f, 0.0714286206f } },
{ { 0.18898176f, -0.109109004f, -0.109109004f, -0.109109004f }, { 0.0714283915f, -0.0714286206f, -0.0714286206f, -0.0714286206f } },
{ { 0.18898176f, 0.109109004f, -0.109109004f, -0.109109004f }, { 0.0714283915f, 0.0714286206f, -0.0714286206f, -0.0714286206f } },
{ { 0.18898176f, 0.000000000f, -0.188982460f, 0.000000000f }, { 0.0714283915f, 0.0000000000f, -0.1237180798f, 0.0000000000f } },
};
/* 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
@@ -205,21 +217,21 @@ ALuint BuildBFormatHrtf(const struct Hrtf *Hrtf, ALfloat (*coeffs)[HRIR_LENGTH][
#define NUM_BANDS 1
BandSplitter splitter;
ALfloat temps[3][HRIR_LENGTH];
ALuint lidx[8], ridx[8];
ALuint lidx[14], ridx[14];
ALuint min_delay = HRTF_HISTORY_LENGTH;
ALuint max_length = 0;
ALuint i, j, c, b;
assert(NumChannels == 4);
for(c = 0;c < 8;c++)
for(c = 0;c < COUNTOF(Ambi3DPoints);c++)
{
ALuint evidx, azidx;
ALuint evoffset;
ALuint azcount;
/* Calculate elevation index. */
evidx = (ALuint)floorf((F_PI_2 + CubePoints[c].elevation) *
evidx = (ALuint)floorf((F_PI_2 + Ambi3DPoints[c].elevation) *
(Hrtf->evCount-1)/F_PI + 0.5f);
evidx = minu(evidx, Hrtf->evCount-1);
@@ -227,7 +239,7 @@ ALuint BuildBFormatHrtf(const struct Hrtf *Hrtf, ALfloat (*coeffs)[HRIR_LENGTH][
evoffset = Hrtf->evOffset[evidx];
/* Calculate azimuth index for this elevation. */
azidx = (ALuint)floorf((F_TAU+CubePoints[c].azimuth) *
azidx = (ALuint)floorf((F_TAU+Ambi3DPoints[c].azimuth) *
azcount/F_TAU + 0.5f) % azcount;
/* Calculate indices for left and right channels. */
@@ -239,7 +251,7 @@ ALuint BuildBFormatHrtf(const struct Hrtf *Hrtf, ALfloat (*coeffs)[HRIR_LENGTH][
memset(temps, 0, sizeof(temps));
bandsplit_init(&splitter, 400.0f / (ALfloat)Hrtf->sampleRate);
for(c = 0;c < 8;c++)
for(c = 0;c < COUNTOF(Ambi3DMatrix);c++)
{
const ALshort *fir;
ALuint delay;
@@ -268,7 +280,7 @@ ALuint BuildBFormatHrtf(const struct Hrtf *Hrtf, ALfloat (*coeffs)[HRIR_LENGTH][
{
ALuint k = 0;
for(j = delay;j < HRIR_LENGTH;++j)
coeffs[i][j][0] += temps[b][k++] * CubeMatrix[c][b][i];
coeffs[i][j][0] += temps[b][k++] * Ambi3DMatrix[c][b][i];
}
}
max_length = maxu(max_length, minu(delay + Hrtf->irSize, HRIR_LENGTH));
@@ -297,7 +309,7 @@ ALuint BuildBFormatHrtf(const struct Hrtf *Hrtf, ALfloat (*coeffs)[HRIR_LENGTH][
{
ALuint k = 0;
for(j = delay;j < HRIR_LENGTH;++j)
coeffs[i][j][1] += temps[b][k++] * CubeMatrix[c][b][i];
coeffs[i][j][1] += temps[b][k++] * Ambi3DMatrix[c][b][i];
}
}
max_length = maxu(max_length, minu(delay + Hrtf->irSize, HRIR_LENGTH));