/// <summary>
/// Computes the volume distribution and center of the shape.
/// </summary>
/// <param name="entries">Mass-weighted entries of the compound.</param>
/// <param name="volume">Summed volume of the constituent shapes. Intersecting volumes get double counted.</param>
/// <param name="volumeDistribution">Volume distribution of the shape.</param>
/// <param name="center">Center of the compound.</param>
public static void ComputeVolumeDistribution(IList<CompoundShapeEntry> entries, out float volume, out Matrix3x3 volumeDistribution, out Vector3 center)
{
center = new Vector3();
float totalWeight = 0;
volume = 0;
for (int i = 0; i < entries.Count; i++)
{
center += entries[i].LocalTransform.Position * entries[i].Weight;
volume += entries[i].Shape.Volume;
totalWeight += entries[i].Weight;
}
if (totalWeight <= 0)
throw new NotFiniteNumberException("Cannot compute distribution; the total weight of a compound shape must be positive.");
float totalWeightInverse = 1 / totalWeight;
totalWeightInverse.Validate();
center *= totalWeightInverse;
volumeDistribution = new Matrix3x3();
for (int i = 0; i < entries.Count; i++)
{
RigidTransform transform = entries[i].LocalTransform;
Matrix3x3 contribution;
TransformContribution(ref transform, ref center, ref entries[i].Shape.volumeDistribution, entries[i].Weight, out contribution);
Matrix3x3.Add(ref volumeDistribution, ref contribution, out volumeDistribution);
}
Matrix3x3.Multiply(ref volumeDistribution, totalWeightInverse, out volumeDistribution);
volumeDistribution.Validate();
}
/// <summary>
/// Computes the volume distribution of the shape.
/// </summary>
/// <returns>Volume distribution of the shape.</returns>
public override Matrix3x3 ComputeVolumeDistribution()
{
var volumeDistribution = new Matrix3x3();
float totalWeight = 0;
for (int i = 0; i < shapes.Count; i++)
{
totalWeight += shapes.Elements[i].Weight;
Matrix3x3 contribution;
GetContribution(shapes.Elements[i].Shape, ref shapes.Elements[i].LocalTransform, ref Toolbox.ZeroVector, shapes.Elements[i].Weight, out contribution);
Matrix3x3.Add(ref contribution, ref volumeDistribution, out volumeDistribution);
}
if (totalWeight <= 0)
throw new NotFiniteNumberException("Cannot compute distribution; the total weight of a compound shape must be positive.");
Matrix3x3.Multiply(ref volumeDistribution, 1 / totalWeight, out volumeDistribution);
volumeDistribution.Validate();
return volumeDistribution;
}
