/// <summary>
/// Convert the target to a QuaternionInterpolationTarget for QuaternionHelper functions
/// </summary>
/// <param name="normalizedWeight">
/// A <see cref="System.Single"/>
/// </param>
/// <returns>
/// A <see cref="QuaternionInterpolationTarget"/>
/// </returns>
public QuaternionInterpolationTarget ToQuatInterpTarget(float normalizedWeight)
{
QuaternionInterpolationTarget t = new QuaternionInterpolationTarget();
t.quaternion = target.rotation;
t.weight = normalizedWeight;
return t;
}
/// <summary>
/// Convert the target to a QuaternionInterpolationTarget for QuaternionHelper functions
/// </summary>
/// <param name="normalizedWeight">
/// A <see cref="System.Single"/>
/// </param>
/// <returns>
/// A <see cref="QuaternionInterpolationTarget"/>
/// </returns>
public QuaternionInterpolationTarget ToQuatInterpTarget(float normalizedWeight)
{
QuaternionInterpolationTarget t = new QuaternionInterpolationTarget();
t.quaternion = target.rotation;
t.weight = normalizedWeight;
return(t);
}
/// <summary>
/// Compute the mean of an array of quaternions
/// </summary>
/// <param name="targets">
/// A <see cref="QuaternionInterpolationTarget[]"/>
/// </param>
/// <returns>
/// A <see cref="Quaternion"/>
/// </returns>
public static Quaternion Mean(QuaternionInterpolationTarget[] targets)
{
Quaternion[] samples = new Quaternion[targets.Length];
for (int i=0; i<targets.Length; i++)
samples[i] = targets[i].quaternion;
return Mean (samples);
}
public static Quaternion InterpolateSlime(QuaternionInterpolationTarget[] normalizedTargets, float oneOverListLength)
{
// get the reference quaternion
Quaternion reference = Mean(normalizedTargets);
// sum the logs of each quaternion in the space of the reference
Vector4 sumOfWeightedQuaternions = Vector4.zero;
for (int i=0; i<normalizedTargets.Length; i++)
sumOfWeightedQuaternions += normalizedTargets[i].weight*Log(Quaternion.Inverse(reference)*normalizedTargets[i].quaternion);
// multiply the reference quaternion by the result
return reference * Exp(sumOfWeightedQuaternions);
}
/// <summary>
/// Perform Slime interpolation across the targets
/// Formula: reference*e^(sum(weight*ln(reference.conjugate*target.rotation)))
/// See p.130, 136: http://alumni.media.mit.edu/~aries/papers/johnson_phd.pdf
/// </summary>
/// <param name="targets">
/// A <see cref="QuaternionInterpolationTarget[]"/>
/// </param>
/// <returns>
/// A <see cref="Quaternion"/>
/// </returns>
public static Quaternion InterpolateSlime(QuaternionInterpolationTarget[] targets)
{
// call other version of method
return InterpolateSlime(NormalizeTargetWeights(targets), 1f/targets.Length);
}
/// <summary>
/// A multiple interpolation algorithm that simply does a sequential nlerp
/// </summary>
/// <param name="normalizedTargets">
/// A <see cref="QuaternionInterpolationTarget[]"/>
/// </param>
/// <returns>
/// A <see cref="Quaternion"/>
/// </returns>
public static Quaternion InterpolateAverage(QuaternionInterpolationTarget[] normalizedTargets)
{
// the candidate return value
Quaternion q = normalizedTargets[0].quaternion;
for (int i=1; i<normalizedTargets.Length; i++)
q = Quaternion.Lerp(q, normalizedTargets[i].quaternion, normalizedTargets[i].weight);
return q;
}
/// <summary>
/// Perform a sequential slerp ala Maya's orientConstraint node
/// </summary>
/// <param name="normalizedTargets">
/// A <see cref="QuaternionInterpolationTarget[]"/>
/// </param>
/// <param name="isShortPath">
/// A <see cref="System.Boolean"/>
/// </param>
/// <param name="cache">
/// A <see cref="Quaternion[]"/>
/// </param>
/// <returns>
/// A <see cref="Quaternion"/>
/// </returns>
public static Quaternion SequentialSlerp(QuaternionInterpolationTarget[] normalizedTargets, bool isShortPath, ref Quaternion[] cache)
{
// the candidate return value
Quaternion q = normalizedTargets[0].quaternion;
for (int i=1; i<normalizedTargets.Length; i++)
{
if (isShortPath) q = Quaternion.Slerp(q, normalizedTargets[i].quaternion, normalizedTargets[i].weight);
else q = SlerpLong(q, normalizedTargets[i].quaternion, normalizedTargets[i].weight);
}
// TODO: if using a caching mode, then do a neighborhood test
// shift the cache and add the new result to the end of it
for (int i=1; i<cache.Length; i++)
cache[i-1] = cache[i];
cache[cache.Length-1] = q;
// return the result
return q;
}
public static Quaternion Interpolate(QuaternionInterpolationTarget[] normalizedTargets, QuaternionInterpolationMode interpType, ref Quaternion[] cache, float oneOverListLength)
{
switch (interpType)
{
case QuaternionInterpolationMode.Average:
return InterpolateAverage(normalizedTargets);
case QuaternionInterpolationMode.Slime:
return InterpolateSlime(normalizedTargets);
case QuaternionInterpolationMode.Longest:
return SequentialSlerp(normalizedTargets, false, ref cache);
default:
return SequentialSlerp(normalizedTargets, true, ref cache);
}
}
/// <summary>
/// Do an interpolation using the specified mode
/// </summary>
/// <param name="normalizedTargets">
/// A <see cref="QuaternionInterpolationTarget[]"/>
/// </param>
/// <param name="interpType">
/// A <see cref="QuaternionInterpolationMode"/>
/// </param>
/// <param name="cache">
/// A <see cref="Quaternion[]"/>
/// </param>
/// <returns>
/// A <see cref="Quaternion"/>
/// </returns>
public static Quaternion Interpolate(QuaternionInterpolationTarget[] normalizedTargets, QuaternionInterpolationMode interpType, ref Quaternion[] cache)
{
// pass in denominator
return Interpolate(normalizedTargets, interpType, ref cache, 1f/normalizedTargets.Length);
}
/// <summary>
/// Normalize the weights of an array of interpolation targets to 1.0
/// </summary>
/// <param name="targets">
/// A <see cref="QuaternionInterpolationTarget[]"/>
/// </param>
/// <returns>
/// A <see cref="QuaternionInterpolationTarget[]"/>
/// </returns>
public static QuaternionInterpolationTarget[] NormalizeTargetWeights(QuaternionInterpolationTarget[] targets)
{
float sumOfAllWeights = 0f;
for (int i=0; i<targets.Length; i++)
sumOfAllWeights += targets[i].weight;
float oneOverSum = 1f/sumOfAllWeights;
for (int i=0; i<targets.Length; i++)
targets[i].weight *= oneOverSum;
return targets;
}
