/// <summary>
///
/// </summary>
/// <returns></returns>
public static double GetArea <V, E, F>(this HeFace <V, E, F> face)
where V : HeVertex <V, E, F>, IPosition3d
where E : Halfedge <V, E, F>
where F : HeFace <V, E, F>
{
return(GetArea(face, IPosition3d <V> .Get));
}
/// <summary>
/// Returns the circumcenter of the face.
/// Assumes face is triangular.
/// http://mathworld.wolfram.com/Incenter.html
/// </summary>
/// <returns></returns>
public static Vec3d GetIncenter <V, E, F>(this HeFace <V, E, F> face)
where V : HeVertex <V, E, F>, IPosition3d
where E : Halfedge <V, E, F>
where F : HeFace <V, E, F>
{
return(GetIncenter(face, IPosition3d <V> .Get));
}
/// <summary>
/// Returns the average position of vertices in the face.
/// </summary>
/// <returns></returns>
public static Vec3d GetBarycenter <V, E, F>(this HeFace <V, E, F> face, Func <V, Vec3d> getPosition)
where V : HeVertex <V, E, F>
where E : Halfedge <V, E, F>
where F : HeFace <V, E, F>
{
return(face.Vertices.Mean(getPosition));
}
/// <summary>
/// Returns the average position of vertices in the face.
/// </summary>
/// <returns></returns>
public static Vec3d GetBarycenter <V, E, F>(this HeFace <V, E, F> face)
where V : HeVertex <V, E, F>, IPosition3d
where E : Halfedge <V, E, F>
where F : HeFace <V, E, F>
{
return(face.Vertices.Mean(IPosition3d <V> .Get));
}
/// <summary>
///
/// </summary>
/// <typeparam name="V"></typeparam>
/// <typeparam name="E"></typeparam>
/// <typeparam name="F"></typeparam>
/// <typeparam name="K"></typeparam>
/// <param name="start"></param>
/// <param name="getKey"></param>
/// <returns></returns>
public static IEnumerable <F> WalkToMax <V, E, F, K>(this HeFace <V, E, F> start, Func <F, K> getKey)
where V : HeVertex <V, E, F>
where E : Halfedge <V, E, F>
where F : HeFace <V, E, F>
where K : IComparable <K>
{
return(MeshUtil.WalkToMax(start.Self, f => f.AdjacentFaces, getKey));
}
/// <summary>
///
/// </summary>
/// <typeparam name="V"></typeparam>
/// <typeparam name="E"></typeparam>
/// <typeparam name="F"></typeparam>
/// <typeparam name="K"></typeparam>
/// <param name="start"></param>
/// <param name="getKey"></param>
/// <returns></returns>
public static F NearestMin <V, E, F, K>(this HeFace <V, E, F> start, Func <F, K> getKey)
where V : HeVertex <V, E, F>
where E : Halfedge <V, E, F>
where F : HeFace <V, E, F>
where K : IComparable <K>
{
return(MeshUtil.NearestMin(start.Self, f => f.AdjacentFaces, getKey));
}
/// <summary>
/// Returns the circumcenter of the face.
/// Assumes face is triangular.
/// http://mathworld.wolfram.com/Incenter.html
/// </summary>
/// <returns></returns>
public static Vec3d GetIncenter <V, E, F>(this HeFace <V, E, F> face, Func <V, Vec3d> getPosition)
where V : HeVertex <V, E, F>
where E : Halfedge <V, E, F>
where F : HeFace <V, E, F>
{
var he = face.First;
return(GeometryUtil.GetIncenter(
getPosition(he.Previous.Start),
getPosition(he.Start),
getPosition(he.Next.Start)
));
}
/// <summary>
/// Returns the unitized sum of halfedge normals in the face.
/// </summary>
/// <returns></returns>
public static Vec3d GetNormal <V, E, F>(this HeFace <V, E, F> face, Func <E, Vec3d> getNormal)
where V : HeVertex <V, E, F>
where E : Halfedge <V, E, F>
where F : HeFace <V, E, F>
{
if (face.IsDegree(3))
{
return(getNormal(face.First).Unit);
}
else
{
return(face.Halfedges.Sum(getNormal).Unit);
}
}
/// <summary>
/// Returns the unitized sum of halfedge normals in the face.
/// </summary>
/// <returns></returns>
public static Vec3d GetNormal <V, E, F>(this HeFace <V, E, F> face, Func <V, Vec3d> getPosition)
where V : HeVertex <V, E, F>
where E : Halfedge <V, E, F>
where F : HeFace <V, E, F>
{
if (face.IsDegree(3))
{
return(face.First.GetNormal(getPosition).Unit);
}
else
{
return(face.Halfedges.Sum(he => he.GetNormal(getPosition)).Unit);
}
}
/// <summary>
/// Returns the planar deviation of this face.
/// </summary>
/// <typeparam name="V"></typeparam>
/// <typeparam name="E"></typeparam>
/// <typeparam name="F"></typeparam>
/// <param name="face"></param>
/// <param name="getPosition"></param>
/// <returns></returns>
public static double GetPlanarity <V, E, F>(this HeFace <V, E, F> face, Func <V, Vec3d> getPosition)
where V : HeVertex <V, E, F>
where E : Halfedge <V, E, F>
where F : HeFace <V, E, F>
{
var he0 = face.First;
var he1 = he0;
var p0 = getPosition(he1.Start);
he1 = he1.Next;
var p1 = getPosition(he1.Start);
he1 = he1.Next;
var p2 = getPosition(he1.Start);
he1 = he1.Next;
// tri case
if (ReferenceEquals(he1, he0))
{
return(0.0);
}
var p3 = getPosition(he1.Start);
he1 = he1.Next;
// quad case
if (ReferenceEquals(he1, he0))
{
return(GeometryUtil.GetQuadPlanarity(p0, p1, p2, p3));
}
// general case
double sum = 0.0;
int count = 0;
foreach (var he in he1.Circulate)
{
sum += GeometryUtil.GetQuadPlanarity(p0, p1, p2, p3);
p0 = p1; p1 = p2; p2 = p3;
p3 = getPosition(he.Start);
}
return(sum / count);
}
