/// <summary>
/// Returns last vertex's id of picked geometry if the geometry represented by <paramref name="stageVertexId"/> belongs to this <paramref name="element"/> instance.
/// <para>Returns false if <paramref name="stageVertexId"/> the primitive is in some other element.</para>
/// </summary>
/// <param name="element"></param>
/// <param name="stageVertexId"></param>
/// <param name="lastVertexId"></param>
/// <returns></returns>
public static bool GetLastVertexIdOfPickedGeometry(this IPickable element,
uint stageVertexId, out uint lastVertexId)
{
lastVertexId = uint.MaxValue;
bool result = false;
if (element != null)
{
if (stageVertexId < element.PickingBaseId) // ID is in some previous element.
{
return(false);
}
uint vertexCount = element.GetVertexCount();
uint id = stageVertexId - element.PickingBaseId;
if (id < vertexCount)
{
lastVertexId = id;
result = true;
}
else // ID is in some subsequent element.
{
result = false;
}
}
return(result);
}