Dima353/openal-soft
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

Use a more efficient method to blend HRTF delays and coefficients

Browse Source
This commit is contained in:
Chris Robinson
2012-08-11 02:16:34 -07:00
parent d6fd52a0e5
commit ea84fee952
1 changed files with 42 additions and 26 deletions
Download Patch File Download Diff File Expand all files Collapse all files
Alc/hrtf.c
+42 -26
View File
@@ -113,8 +113,8 @@ ALfloat CalcHrtfDelta(ALfloat oldGain, ALfloat newGain, const ALfloat olddir[3],
void GetLerpedHrtfCoeffs(const struct Hrtf *Hrtf, ALfloat elevation, ALfloat azimuth, ALfloat gain, ALfloat (*coeffs)[2], ALuint *delays)
{
ALuint evidx[2], azidx[2];
ALfloat mu[3];
ALuint lidx[4], ridx[4];
ALfloat mu[3], blend[4];
ALuint i;
// Claculate elevation indices and interpolation factor.
@@ -142,6 +142,12 @@ void GetLerpedHrtfCoeffs(const struct Hrtf *Hrtf, ALfloat elevation, ALfloat azi
ridx[2] = evOffset[evidx[1]] + ((azCount[evidx[1]]-azidx[0]) % azCount[evidx[1]]);
ridx[3] = evOffset[evidx[1]] + ((azCount[evidx[1]]-azidx[1]) % azCount[evidx[1]]);
/* Calculate 4 blending weights for 2D bilinear interpolation */
blend[0] = (1.0f-mu[0]) * (1.0f-mu[2]);
blend[1] = ( mu[0]) * (1.0f-mu[2]);
blend[2] = (1.0f-mu[1]) * ( mu[2]);
blend[3] = ( mu[1]) * ( mu[2]);
// Calculate the normalized and attenuated HRIR coefficients using linear
// interpolation when there is enough gain to warrant it. Zero the
// coefficients if gain is too low.
@@ -150,12 +156,14 @@ void GetLerpedHrtfCoeffs(const struct Hrtf *Hrtf, ALfloat elevation, ALfloat azi
gain *= 1.0f/32767.0f;
for(i = 0;i < HRIR_LENGTH;i++)
{
coeffs[i][0] = lerp(lerp(Hrtf->coeffs[lidx[0]][i], Hrtf->coeffs[lidx[1]][i], mu[0]),
lerp(Hrtf->coeffs[lidx[2]][i], Hrtf->coeffs[lidx[3]][i], mu[1]),
mu[2]) * gain;
coeffs[i][1] = lerp(lerp(Hrtf->coeffs[ridx[0]][i], Hrtf->coeffs[ridx[1]][i], mu[0]),
lerp(Hrtf->coeffs[ridx[2]][i], Hrtf->coeffs[ridx[3]][i], mu[1]),
mu[2]) * gain;
coeffs[i][0] = (Hrtf->coeffs[lidx[0]][i]*blend[0] +
Hrtf->coeffs[lidx[1]][i]*blend[1] +
Hrtf->coeffs[lidx[2]][i]*blend[2] +
Hrtf->coeffs[lidx[3]][i]*blend[3]) * gain;
coeffs[i][1] = (Hrtf->coeffs[ridx[0]][i]*blend[0] +
Hrtf->coeffs[ridx[1]][i]*blend[1] +
Hrtf->coeffs[ridx[2]][i]*blend[2] +
Hrtf->coeffs[ridx[3]][i]*blend[3]) * gain;
}
}
else
@@ -168,12 +176,12 @@ void GetLerpedHrtfCoeffs(const struct Hrtf *Hrtf, ALfloat elevation, ALfloat azi
}
// Calculate the HRIR delays using linear interpolation.
delays[0] = fastf2u(lerp(lerp(Hrtf->delays[lidx[0]], Hrtf->delays[lidx[1]], mu[0]),
lerp(Hrtf->delays[lidx[2]], Hrtf->delays[lidx[3]], mu[1]),
mu[2]) + 0.5f) << HRTFDELAY_BITS;
delays[1] = fastf2u(lerp(lerp(Hrtf->delays[ridx[0]], Hrtf->delays[ridx[1]], mu[0]),
lerp(Hrtf->delays[ridx[2]], Hrtf->delays[ridx[3]], mu[1]),
mu[2]) + 0.5f) << HRTFDELAY_BITS;
delays[0] = fastf2u(Hrtf->delays[lidx[0]]*blend[0] + Hrtf->delays[lidx[1]]*blend[1] +
Hrtf->delays[lidx[2]]*blend[2] + Hrtf->delays[lidx[3]]*blend[3] +
0.5f) << HRTFDELAY_BITS;
delays[1] = fastf2u(Hrtf->delays[ridx[0]]*blend[0] + Hrtf->delays[ridx[1]]*blend[1] +
Hrtf->delays[ridx[2]]*blend[2] + Hrtf->delays[ridx[3]]*blend[3] +
0.5f) << HRTFDELAY_BITS;
}
// Calculates the moving HRIR target coefficients, target delays, and
@@ -186,8 +194,8 @@ ALuint GetMovingHrtfCoeffs(const struct Hrtf *Hrtf, ALfloat elevation, ALfloat a
{
ALuint evidx[2], azidx[2];
ALuint lidx[4], ridx[4];
ALfloat mu[3], blend[4];
ALfloat left, right;
ALfloat mu[3];
ALfloat step;
ALuint i;
@@ -220,6 +228,12 @@ ALuint GetMovingHrtfCoeffs(const struct Hrtf *Hrtf, ALfloat elevation, ALfloat a
delta = maxf(floorf(delta*(Hrtf->sampleRate*0.015f) + 0.5f), 1.0f);
step = 1.0f / delta;
/* Calculate 4 blending weights for 2D bilinear interpolation */
blend[0] = (1.0f-mu[0]) * (1.0f-mu[2]);
blend[1] = ( mu[0]) * (1.0f-mu[2]);
blend[2] = (1.0f-mu[1]) * ( mu[2]);
blend[3] = ( mu[1]) * ( mu[2]);
// Calculate the normalized and attenuated target HRIR coefficients using
// linear interpolation when there is enough gain to warrant it. Zero
// the target coefficients if gain is too low. Then calculate the
@@ -233,12 +247,14 @@ ALuint GetMovingHrtfCoeffs(const struct Hrtf *Hrtf, ALfloat elevation, ALfloat a
left = coeffs[i][0] - (coeffStep[i][0] * counter);
right = coeffs[i][1] - (coeffStep[i][1] * counter);
coeffs[i][0] = lerp(lerp(Hrtf->coeffs[lidx[0]][i], Hrtf->coeffs[lidx[1]][i], mu[0]),
lerp(Hrtf->coeffs[lidx[2]][i], Hrtf->coeffs[lidx[3]][i], mu[1]),
mu[2]) * gain;
coeffs[i][1] = lerp(lerp(Hrtf->coeffs[ridx[0]][i], Hrtf->coeffs[ridx[1]][i], mu[0]),
lerp(Hrtf->coeffs[ridx[2]][i], Hrtf->coeffs[ridx[3]][i], mu[1]),
mu[2]) * gain;
coeffs[i][0] = (Hrtf->coeffs[lidx[0]][i]*blend[0] +
Hrtf->coeffs[lidx[1]][i]*blend[1] +
Hrtf->coeffs[lidx[2]][i]*blend[2] +
Hrtf->coeffs[lidx[3]][i]*blend[3]) * gain;
coeffs[i][1] = (Hrtf->coeffs[ridx[0]][i]*blend[0] +
Hrtf->coeffs[ridx[1]][i]*blend[1] +
Hrtf->coeffs[ridx[2]][i]*blend[2] +
Hrtf->coeffs[ridx[3]][i]*blend[3]) * gain;
coeffStep[i][0] = step * (coeffs[i][0] - left);
coeffStep[i][1] = step * (coeffs[i][1] - right);
@@ -265,12 +281,12 @@ ALuint GetMovingHrtfCoeffs(const struct Hrtf *Hrtf, ALfloat elevation, ALfloat a
left = (ALfloat)(delays[0] - (delayStep[0] * counter));
right = (ALfloat)(delays[1] - (delayStep[1] * counter));
delays[0] = fastf2u(lerp(lerp(Hrtf->delays[lidx[0]], Hrtf->delays[lidx[1]], mu[0]),
lerp(Hrtf->delays[lidx[2]], Hrtf->delays[lidx[3]], mu[1]),
mu[2]) + 0.5f) << HRTFDELAY_BITS;
delays[1] = fastf2u(lerp(lerp(Hrtf->delays[ridx[0]], Hrtf->delays[ridx[1]], mu[0]),
lerp(Hrtf->delays[ridx[2]], Hrtf->delays[ridx[3]], mu[1]),
mu[2]) + 0.5f) << HRTFDELAY_BITS;
delays[0] = fastf2u(Hrtf->delays[lidx[0]]*blend[0] + Hrtf->delays[lidx[1]]*blend[1] +
Hrtf->delays[lidx[2]]*blend[2] + Hrtf->delays[lidx[3]]*blend[3] +
0.5f) << HRTFDELAY_BITS;
delays[1] = fastf2u(Hrtf->delays[ridx[0]]*blend[0] + Hrtf->delays[ridx[1]]*blend[1] +
Hrtf->delays[ridx[2]]*blend[2] + Hrtf->delays[ridx[3]]*blend[3] +
0.5f) << HRTFDELAY_BITS;
delayStep[0] = fastf2i(step * (delays[0] - left));
delayStep[1] = fastf2i(step * (delays[1] - right));