public OBJFileParser Create(int recursionLevel)
{
this.geometry = new OBJFileParser();
this.middlePointIndexCache = new Dictionary <long, int>();
this.index = 0;
// create 12 vertices of a icosahedron
var t = (1.0 + Math.Sqrt(5.0)) / 2.0;
addVertex(new Point(-1, t, 0));
addVertex(new Point(1, t, 0));
addVertex(new Point(-1, -t, 0));
addVertex(new Point(1, -t, 0));
addVertex(new Point(0, -1, t));
addVertex(new Point(0, 1, t));
addVertex(new Point(0, -1, -t));
addVertex(new Point(0, 1, -t));
addVertex(new Point(t, 0, -1));
addVertex(new Point(t, 0, 1));
addVertex(new Point(-t, 0, -1));
addVertex(new Point(-t, 0, 1));
// create 20 triangles of the icosahedron
var faces = new List <Tri>();
// 5 faces around point 0
faces.Add(new Tri(0, 11, 5));
faces.Add(new Tri(0, 5, 1));
faces.Add(new Tri(0, 1, 7));
faces.Add(new Tri(0, 7, 10));
faces.Add(new Tri(0, 10, 11));
// 5 adjacent faces
faces.Add(new Tri(1, 5, 9));
faces.Add(new Tri(5, 11, 4));
faces.Add(new Tri(11, 10, 2));
faces.Add(new Tri(10, 7, 6));
faces.Add(new Tri(7, 1, 8));
// 5 faces around point 3
faces.Add(new Tri(3, 9, 4));
faces.Add(new Tri(3, 4, 2));
faces.Add(new Tri(3, 2, 6));
faces.Add(new Tri(3, 6, 8));
faces.Add(new Tri(3, 8, 9));
// 5 adjacent faces
faces.Add(new Tri(4, 9, 5));
faces.Add(new Tri(2, 4, 11));
faces.Add(new Tri(6, 2, 10));
faces.Add(new Tri(8, 6, 7));
faces.Add(new Tri(9, 8, 1));
// refine triangles
for (int i = 0; i < recursionLevel; i++)
{
var faces2 = new List <Tri>();
foreach (var tri in faces)
{
// replace triangle by 4 triangles
int a = getMiddlePoint(tri.v1, tri.v2);
int b = getMiddlePoint(tri.v2, tri.v3);
int c = getMiddlePoint(tri.v3, tri.v1);
faces2.Add(new Tri(tri.v1, a, c));
faces2.Add(new Tri(tri.v2, b, a));
faces2.Add(new Tri(tri.v3, c, b));
faces2.Add(new Tri(a, b, c));
}
faces = faces2;
}
// done, now add triangles to mesh
Point origin = new Point(0, 0, 0);
foreach (var tri in faces)
{
// Create the point normals for the smoothing
Vector n0 = (geometry.Verticies[tri.v1] - origin).Normalize();
Vector n1 = (geometry.Verticies[tri.v2] - origin).Normalize();
Vector n2 = (geometry.Verticies[tri.v3] - origin).Normalize();
// texture map coordinates
Point t0 = new Point((geometry.Verticies[tri.v1].X + 1) / 2, (geometry.Verticies[tri.v1].Y + 1) / 2, 0);
Point t1 = new Point((geometry.Verticies[tri.v2].X + 1) / 2, (geometry.Verticies[tri.v2].Y + 1) / 2, 0);
Point t2 = new Point((geometry.Verticies[tri.v3].X + 1) / 2, (geometry.Verticies[tri.v3].Y + 1) / 2, 0);
// Create the texture maps for each vertex
SmoothTriangle st = new SmoothTriangle(geometry.Verticies[tri.v1], geometry.Verticies[tri.v2], geometry.Verticies[tri.v3]);
st.AddNormals(n0, n1, n2);
st.AddTexture(t0, t1, t2);
this.geometry.AddToCurrentGroup(st);
}
return(this.geometry);
}
