/* Calculates the moving HRIR target coefficients, target delays, and
* stepping values for the given polar elevation and azimuth in radians.
* Linear interpolation is used to increase the apparent resolution of the
* HRIR data set. The coefficients are also normalized and attenuated by the
* specified gain. Stepping resolution and count is determined using the
* given delta factor between 0.0 and 1.0.
*/
ALuint GetMovingHrtfCoeffs(const struct Hrtf *Hrtf, ALfloat elevation, ALfloat azimuth, ALfloat gain, ALfloat delta, ALint counter, ALfloat (*coeffs)[2], ALuint *delays, ALfloat (*coeffStep)[2], ALint *delayStep)
{
ALuint evidx[2], azidx[2];
ALuint lidx[4], ridx[4];
ALfloat mu[3], blend[4];
ALfloat left, right;
ALfloat step;
ALuint i;
// Claculate elevation indices and interpolation factor.
CalcEvIndices(Hrtf, elevation, evidx, &mu[2]);
// Calculate azimuth indices and interpolation factor for the first
// elevation.
CalcAzIndices(Hrtf, evidx[0], azimuth, azidx, &mu[0]);
// Calculate the first set of linear HRIR indices for left and right
// channels.
lidx[0] = Hrtf->evOffset[evidx[0]] + azidx[0];
lidx[1] = Hrtf->evOffset[evidx[0]] + azidx[1];
ridx[0] = Hrtf->evOffset[evidx[0]] + ((Hrtf->azCount[evidx[0]]-azidx[0]) % Hrtf->azCount[evidx[0]]);
ridx[1] = Hrtf->evOffset[evidx[0]] + ((Hrtf->azCount[evidx[0]]-azidx[1]) % Hrtf->azCount[evidx[0]]);
// Calculate azimuth indices and interpolation factor for the second
// elevation.
CalcAzIndices(Hrtf, evidx[1], azimuth, azidx, &mu[1]);
// Calculate the second set of linear HRIR indices for left and right
// channels.
lidx[2] = Hrtf->evOffset[evidx[1]] + azidx[0];
lidx[3] = Hrtf->evOffset[evidx[1]] + azidx[1];
ridx[2] = Hrtf->evOffset[evidx[1]] + ((Hrtf->azCount[evidx[1]]-azidx[0]) % Hrtf->azCount[evidx[1]]);
ridx[3] = Hrtf->evOffset[evidx[1]] + ((Hrtf->azCount[evidx[1]]-azidx[1]) % Hrtf->azCount[evidx[1]]);
// Calculate the stepping parameters.
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 HRIR delays using linear interpolation. Then calculate
* the delay stepping values using the target and previous running
* delays.
*/
left = (ALfloat)(delays[0] - (delayStep[0] * counter));
right = (ALfloat)(delays[1] - (delayStep[1] * counter));
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));
/* Calculate the sample offsets for the HRIR indices. */
lidx[0] *= Hrtf->irSize;
lidx[1] *= Hrtf->irSize;
lidx[2] *= Hrtf->irSize;
lidx[3] *= Hrtf->irSize;
ridx[0] *= Hrtf->irSize;
ridx[1] *= Hrtf->irSize;
ridx[2] *= Hrtf->irSize;
ridx[3] *= Hrtf->irSize;
/* 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
* coefficient stepping values using the target and previous running
* coefficients.
*/
if(gain > 0.0001f)
{
gain *= 1.0f/32767.0f;
for(i = 0;i < HRIR_LENGTH;i++)
{
left = coeffs[i][0] - (coeffStep[i][0] * counter);
right = coeffs[i][1] - (coeffStep[i][1] * counter);
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);
}
}
else
{
for(i = 0;i < HRIR_LENGTH;i++)
{
left = coeffs[i][0] - (coeffStep[i][0] * counter);
right = coeffs[i][1] - (coeffStep[i][1] * counter);
coeffs[i][0] = 0.0f;
coeffs[i][1] = 0.0f;
coeffStep[i][0] = step * -left;
coeffStep[i][1] = step * -right;
}
}
/* The stepping count is the number of samples necessary for the HRIR to
* complete its transition. The mixer will only apply stepping for this
* many samples.
*/
return fastf2u(delta);
}
// Calculates the moving HRIR target coefficients, target delays, and
// stepping values for the given polar elevation and azimuth in radians.
// Linear interpolation is used to increase the apparent resolution of the
// HRIR dataset. The coefficients are also normalized and attenuated by the
// specified gain. Stepping resolution and count is determined using the
// given delta factor between 0.0 and 1.0.
ALuint GetMovingHrtfCoeffs(const struct Hrtf *Hrtf, ALfloat elevation, ALfloat azimuth, ALfloat gain, ALfloat delta, ALint counter, ALfloat (*coeffs)[2], ALuint *delays, ALfloat (*coeffStep)[2], ALint *delayStep)
{
ALuint evidx[2], azidx[2];
ALuint lidx[4], ridx[4];
ALfloat left, right;
ALfloat mu[3];
ALfloat step;
ALuint i;
// Claculate elevation indices and interpolation factor.
CalcEvIndices(elevation, evidx, &mu[2]);
// Calculate azimuth indices and interpolation factor for the first
// elevation.
CalcAzIndices(evidx[0], azimuth, azidx, &mu[0]);
// Calculate the first set of linear HRIR indices for left and right
// channels.
lidx[0] = evOffset[evidx[0]] + azidx[0];
lidx[1] = evOffset[evidx[0]] + azidx[1];
ridx[0] = evOffset[evidx[0]] + ((azCount[evidx[0]]-azidx[0]) % azCount[evidx[0]]);
ridx[1] = evOffset[evidx[0]] + ((azCount[evidx[0]]-azidx[1]) % azCount[evidx[0]]);
// Calculate azimuth indices and interpolation factor for the second
// elevation.
CalcAzIndices(evidx[1], azimuth, azidx, &mu[1]);
// Calculate the second set of linear HRIR indices for left and right
// channels.
lidx[2] = evOffset[evidx[1]] + azidx[0];
lidx[3] = evOffset[evidx[1]] + azidx[1];
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 the stepping parameters.
delta = maxf(aluFloor(delta*(Hrtf->sampleRate*0.015f) + 0.5f), 1.0f);
step = 1.0f / delta;
// 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
// coefficient stepping values using the target and previous running
// coefficients.
if(gain > 0.0001f)
{
gain *= 1.0f/32767.0f;
for(i = 0;i < HRIR_LENGTH;i++)
{
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;
coeffStep[i][0] = step * (coeffs[i][0] - left);
coeffStep[i][1] = step * (coeffs[i][1] - right);
}
}
else
{
for(i = 0;i < HRIR_LENGTH;i++)
{
left = coeffs[i][0] - (coeffStep[i][0] * counter);
right = coeffs[i][1] - (coeffStep[i][1] * counter);
coeffs[i][0] = 0.0f;
coeffs[i][1] = 0.0f;
coeffStep[i][0] = step * -left;
coeffStep[i][1] = step * -right;
}
}
// Calculate the HRIR delays using linear interpolation. Then calculate
// the delay stepping values using the target and previous running
// delays.
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]) * 65536.0f);
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]) * 65536.0f);
delayStep[0] = fastf2i(step * (delays[0] - left));
delayStep[1] = fastf2i(step * (delays[1] - right));
// The stepping count is the number of samples necessary for the HRIR to
// complete its transition. The mixer will only apply stepping for this
// many samples.
return fastf2u(delta);
}
/* Calculates static HRIR coefficients and delays for the given polar
* elevation and azimuth in radians. Linear interpolation is used to
* increase the apparent resolution of the HRIR data set. The coefficients
* are also normalized and attenuated by the specified gain.
*/
void GetLerpedHrtfCoeffs(const struct Hrtf *Hrtf, ALfloat elevation, ALfloat azimuth, ALfloat gain, ALfloat (*coeffs)[2], ALuint *delays)
{
ALuint evidx[2], azidx[2];
ALuint lidx[4], ridx[4];
ALfloat mu[3], blend[4];
ALuint i;
// Claculate elevation indices and interpolation factor.
CalcEvIndices(Hrtf, elevation, evidx, &mu[2]);
// Calculate azimuth indices and interpolation factor for the first
// elevation.
CalcAzIndices(Hrtf, evidx[0], azimuth, azidx, &mu[0]);
// Calculate the first set of linear HRIR indices for left and right
// channels.
lidx[0] = Hrtf->evOffset[evidx[0]] + azidx[0];
lidx[1] = Hrtf->evOffset[evidx[0]] + azidx[1];
ridx[0] = Hrtf->evOffset[evidx[0]] + ((Hrtf->azCount[evidx[0]]-azidx[0]) % Hrtf->azCount[evidx[0]]);
ridx[1] = Hrtf->evOffset[evidx[0]] + ((Hrtf->azCount[evidx[0]]-azidx[1]) % Hrtf->azCount[evidx[0]]);
// Calculate azimuth indices and interpolation factor for the second
// elevation.
CalcAzIndices(Hrtf, evidx[1], azimuth, azidx, &mu[1]);
// Calculate the second set of linear HRIR indices for left and right
// channels.
lidx[2] = Hrtf->evOffset[evidx[1]] + azidx[0];
lidx[3] = Hrtf->evOffset[evidx[1]] + azidx[1];
ridx[2] = Hrtf->evOffset[evidx[1]] + ((Hrtf->azCount[evidx[1]]-azidx[0]) % Hrtf->azCount[evidx[1]]);
ridx[3] = Hrtf->evOffset[evidx[1]] + ((Hrtf->azCount[evidx[1]]-azidx[1]) % Hrtf->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 HRIR delays using linear interpolation. */
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;
/* Calculate the sample offsets for the HRIR indices. */
lidx[0] *= Hrtf->irSize;
lidx[1] *= Hrtf->irSize;
lidx[2] *= Hrtf->irSize;
lidx[3] *= Hrtf->irSize;
ridx[0] *= Hrtf->irSize;
ridx[1] *= Hrtf->irSize;
ridx[2] *= Hrtf->irSize;
ridx[3] *= Hrtf->irSize;
/* 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.
*/
if(gain > 0.0001f)
{
gain *= 1.0f/32767.0f;
for(i = 0;i < Hrtf->irSize;i++)
{
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
{
for(i = 0;i < Hrtf->irSize;i++)
{
coeffs[i][0] = 0.0f;
coeffs[i][1] = 0.0f;
}
}
}
// Calculates static HRIR coefficients and delays for the given polar
// elevation and azimuth in radians. Linear interpolation is used to
// increase the apparent resolution of the HRIR dataset. The coefficients
// are also normalized and attenuated by the specified gain.
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];
ALuint i;
// Claculate elevation indices and interpolation factor.
CalcEvIndices(elevation, evidx, &mu[2]);
// Calculate azimuth indices and interpolation factor for the first
// elevation.
CalcAzIndices(evidx[0], azimuth, azidx, &mu[0]);
// Calculate the first set of linear HRIR indices for left and right
// channels.
lidx[0] = evOffset[evidx[0]] + azidx[0];
lidx[1] = evOffset[evidx[0]] + azidx[1];
ridx[0] = evOffset[evidx[0]] + ((azCount[evidx[0]]-azidx[0]) % azCount[evidx[0]]);
ridx[1] = evOffset[evidx[0]] + ((azCount[evidx[0]]-azidx[1]) % azCount[evidx[0]]);
// Calculate azimuth indices and interpolation factor for the second
// elevation.
CalcAzIndices(evidx[1], azimuth, azidx, &mu[1]);
// Calculate the second set of linear HRIR indices for left and right
// channels.
lidx[2] = evOffset[evidx[1]] + azidx[0];
lidx[3] = evOffset[evidx[1]] + azidx[1];
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 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.
if(gain > 0.0001f)
{
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;
}
}
else
{
for(i = 0;i < HRIR_LENGTH;i++)
{
coeffs[i][0] = 0.0f;
coeffs[i][1] = 0.0f;
}
}
// 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]) * 65536.0f);
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]) * 65536.0f);
}