/// <summary>
/// Gets the <see cref="MaterialProperties"/> for the given rigid body, position and shape
/// feature.
/// </summary>
/// <param name="body">The rigid body.</param>
/// <param name="positionLocal">
/// The local position on the rigid body for which the material properties should be returned.
/// </param>
/// <param name="featureIndex">
/// The index of the shape feature from which the material properties are needed. For a
/// <see cref="CompositeShape"/> the feature index is the index of the child of the composite
/// shape. For a <see cref="TriangleMeshShape"/> the feature index is the index of a triangle.
/// </param>
/// <returns>
/// The <see cref="MaterialProperties"/> of the given rigid body at the given position and
/// child feature.
/// </returns>
/// <exception cref="ArgumentNullException">
/// <paramref name="body"/> is <see langword="null"/>.
/// </exception>
public MaterialProperties GetProperties(RigidBody body, Vector3 positionLocal, int featureIndex)
{
if (body == null)
{
throw new ArgumentNullException("body");
}
// No child feature - use default material.
if (featureIndex < 0)
{
return(DefaultMaterial.GetProperties(body, positionLocal, featureIndex));
}
IMaterial material = null;
// Try to find entry in list.
if (featureIndex < Materials.Count)
{
material = Materials[featureIndex];
}
if (material == null)
{
// Check if feature is a rigid body.
var compositeShape = body.Shape as CompositeShape;
if (compositeShape != null && featureIndex < compositeShape.Children.Count)
{
var childBody = compositeShape.Children[featureIndex] as RigidBody;
if (childBody != null)
{
material = childBody.Material;
}
}
}
if (material == null)
{
// Fallback: Use DefaultMaterial.
material = DefaultMaterial;
}
return(material.GetProperties(body, positionLocal, featureIndex));
}