private Mesh CreateIcosphere(int recursionLevel)
{
Mesh mesh = new Icosahedron();
if (recursionLevel == 0)
{
return(mesh);
}
//Add Verts to temp vert list
foreach (var vert in mesh.Vertices)
{
AddNormalizedVertex(vert);
}
//Subdivide triangles
for (var i = 0; i < recursionLevel; i++)
{
var faces2 = new List <ushort>();
var tri = new List <ushort>();
for (var k = 0; k < mesh.Triangles.Length; k++)
{
tri.Add(mesh.Triangles[k]);
if (tri.Count != 3)
{
continue;
}
//Replace triangle by four triangles.
var a = MiddlePoint(tri[0], tri[1]);
var b = MiddlePoint(tri[1], tri[2]);
var c = MiddlePoint(tri[2], tri[0]);
var temp = new List <ushort>
{
tri[0], a, c,
tri[1], b, a,
tri[2], c, b,
a, b, c
};
faces2.AddRange(temp);
tri = new List <ushort>();
}
mesh.Triangles = faces2.ToArray();
}
mesh.Vertices = _sphereVertices.ToArray();
NormalAndUvHelper.CreateVertexNormals(mesh);
mesh.UVs = new float2[mesh.Vertices.Length];
for (var i = 0; i < mesh.Vertices.Length; i++)
{
mesh.UVs[i] = new float2(0.5f + ((float)System.Math.Atan2(mesh.Vertices[i].z, mesh.Vertices[i].x) / (2 * M.Pi)), 0.5f - ((float)System.Math.Asin(mesh.Vertices[i].y) / M.Pi));
}
return(mesh);
}
/// <summary>
/// Initializes a new instance of the <see cref="Icosahedron" /> class.
/// All Vertices of the Icosahedron are lying on the unit sphere.
/// </summary>
public Icosahedron()
{
//Create the 12 vertices of a icosahedron.
var t = (float)(1.0 + System.Math.Sqrt(5.0)) / 2.0f;
var verts = new List <float3>
{
new float3(-1, t, 0),
new float3(1, t, 0),
new float3(-1, -t, 0),
new float3(1, -t, 0),
new float3(0, -1, t),
new float3(0, 1, t),
new float3(0, -1, -t),
new float3(0, 1, -t),
new float3(t, 0, -1),
new float3(t, 0, 1),
new float3(-t, 0, -1),
new float3(-t, 0, 1)
};
//Normalize to get the unit icosahedron.
for (var i = 0; i < verts.Count; i++)
{
var vert = verts[i];
vert = vert.Normalize();
verts[i] = vert;
}
Vertices = verts.ToArray();
Triangles = new ushort[]
{
5, 11, 0,
1, 5, 0,
7, 1, 0,
10, 7, 0,
11, 10, 0,
9, 5, 1,
4, 11, 5,
2, 10, 11,
6, 7, 10,
8, 1, 7,
4, 9, 3,
2, 4, 3,
6, 2, 3,
8, 6, 3,
9, 8, 3,
5, 9, 4,
11, 4, 2,
10, 2, 6,
7, 6, 8,
1, 8, 9
};
Normals = new float3[] { };
NormalAndUvHelper.CreateVertexNormals(this);
UVs = CreateUVs();
for (var i = 0; i < Vertices.Length; i++)
{
UVs[i] =
new float2(0.5f + ((float)System.Math.Atan2(Vertices[i].z, Vertices[i].x) / (2 * M.Pi)),
0.5f - ((float)System.Math.Asin(Vertices[i].y) / M.Pi));
}
}
