/// <summary>
/// Gets the gain at a given frequency.
/// </summary>
public double this[double frequency] {
get {
int bandCount = bands.Count;
if (bandCount == 0)
{
return(0);
}
int nextBand = 0, prevBand = 0;
while (nextBand != bandCount && bands[nextBand].Frequency < frequency)
{
prevBand = nextBand;
++nextBand;
}
if (nextBand != bandCount && nextBand != 0)
{
return(QMath.Lerp(bands[prevBand].Gain, bands[nextBand].Gain,
QMath.LerpInverse(bands[prevBand].Frequency, bands[nextBand].Frequency, frequency)));
}
return(bands[prevBand].Gain);
}
}
/// <summary>
/// Generate the left/right ear filters.
/// </summary>
/// <param name="right">The object is to the right of the <see cref="Listener"/>'s forward vector</param>
/// <param name="samples">Single-channel downmixed samples to process</param>
public void Generate(bool right, float[] samples)
{
float dirMul = -90;
if (right)
{
dirMul = 90;
}
Vector3 sourceForward = new Vector3(0, dirMul, 0).RotateInverse(source.listener.Rotation).PlaceInSphere(),
dir = source.Position - source.listener.Position;
float distance = dir.Length(),
rawAngle = (float)Math.Acos(Vector3.Dot(sourceForward, dir) / distance),
angle = rawAngle * VectorExtensions.Rad2Deg;
distance /= distanceFactor;
// Find bounding angles with discrete impulses
int smallerAngle = 0;
while (smallerAngle < angles.Length && angles[smallerAngle] < angle)
{
++smallerAngle;
}
if (smallerAngle != 0)
{
--smallerAngle;
}
int largerAngle = smallerAngle + 1;
if (largerAngle == angles.Length)
{
largerAngle = angles.Length - 1;
}
float angleRatio = Math.Min(QMath.LerpInverse(angles[smallerAngle], angles[largerAngle], angle), 1);
// Find bounding distances with discrete impulses
int smallerDistance = 0;
while (smallerDistance < distances.Length && distances[smallerDistance] < distance)
{
++smallerDistance;
}
if (smallerDistance != 0)
{
--smallerDistance;
}
int largerDistance = smallerDistance + 1;
if (largerDistance == distances.Length)
{
largerDistance = distances.Length - 1;
}
float distanceRatio =
Math.Clamp(QMath.LerpInverse(distances[smallerDistance], distances[largerDistance], distance), 0, 1);
// Find impulse candidates and their weight
float[][] candidates = new float[4][] {
impulses[smallerAngle][smallerDistance],
impulses[smallerAngle][largerDistance],
impulses[largerAngle][smallerDistance],
impulses[largerAngle][largerDistance]
};
float[] gains = new float[4] {
(float)Math.Sqrt((1 - angleRatio) * (1 - distanceRatio)),
(float)Math.Sqrt((1 - angleRatio) * distanceRatio),
(float)Math.Sqrt(angleRatio * (1 - distanceRatio)),
(float)Math.Sqrt(angleRatio * distanceRatio)
};
// Apply the ear canal's response
Array.Clear(filter.Impulse, 0, filterSize);
for (int candidate = 0; candidate < candidates.Length; ++candidate)
{
WaveformUtils.Mix(candidates[candidate], filter.Impulse, gains[candidate]);
}
filter.Process(samples);
// Apply gains
float angleDiff = (float)(Math.Sin(rawAngle) * .097f);
float ratioDiff = (distance + angleDiff) * (VirtualizerFilter.referenceDistance - angleDiff) /
((distance - angleDiff) * (VirtualizerFilter.referenceDistance + angleDiff));
ratioDiff *= ratioDiff;
if (right)
{
if (ratioDiff < 1)
{
RightGain = ratioDiff;
}
else
{
LeftGain = 1 / ratioDiff;
}
}
else
{
if (ratioDiff < 1)
{
LeftGain = ratioDiff;
}
else
{
RightGain = 1 / ratioDiff;
}
}
}