/// <summary>
/// Returns true if vertex lies on the edge of triangle mesh
/// </summary>
/// <param name="vertex"></param>
/// <returns></returns>
public static bool IsOnEdge(Vector3 vertex, SceneBrep scene)
{
bool onEdge = false;
var handle = scene.GetVertex(vertex);
List <int> trianglePtr = new List <int>();
// get triangles
for (int i = 0; i < scene.vertexPtr.Count; i++)
{
if (scene.vertexPtr[i] == handle)
{
if (i % 3 == 0)
{
trianglePtr.Add(i / 3);
}
else if (i % 3 == 1)
{
trianglePtr.Add((i - 1) / 3);
}
else if (i % 3 == 2)
{
trianglePtr.Add((i - 2) / 3);
}
}
}
// is triangle on edge?
foreach (var ptr in trianglePtr)
{
// get handle of corners of triangle
var c1 = Scene3D.SceneBrep.tCorner(ptr);
var c2 = c1 + 1;
var c3 = c1 + 2;
if (scene.cOpposite(c1) == -1)
{
onEdge = true;
}
else if (scene.cOpposite(c2) == -1)
{
onEdge = true;
}
else if (scene.cOpposite(c3) == -1)
{
onEdge = true;
}
}
return(onEdge);
}
