public static void Create(GameObject gameObject, float height, CelestialBody celestialBody)
{
float radius = 1;
if (celestialBody == null)
{
radius = height;
}
MeshFilter filter = gameObject.AddComponent <MeshFilter>();
Mesh mesh = filter.mesh;
mesh.Clear();
List <Vector3> vertList = new List <Vector3>();
Dictionary <long, int> middlePointIndexCache = new Dictionary <long, int>();
int recursionLevel = 4;
if (celestialBody != null)
{
recursionLevel = 6;
}
// create 12 vertices of a icosahedron
float t = (1f + Mathf.Sqrt(5f)) / 2f;
vertList.Add(new Vector3(-1f, t, 0f).normalized *radius);
vertList.Add(new Vector3(1f, t, 0f).normalized *radius);
vertList.Add(new Vector3(-1f, -t, 0f).normalized *radius);
vertList.Add(new Vector3(1f, -t, 0f).normalized *radius);
vertList.Add(new Vector3(0f, -1f, t).normalized *radius);
vertList.Add(new Vector3(0f, 1f, t).normalized *radius);
vertList.Add(new Vector3(0f, -1f, -t).normalized *radius);
vertList.Add(new Vector3(0f, 1f, -t).normalized *radius);
vertList.Add(new Vector3(t, 0f, -1f).normalized *radius);
vertList.Add(new Vector3(t, 0f, 1f).normalized *radius);
vertList.Add(new Vector3(-t, 0f, -1f).normalized *radius);
vertList.Add(new Vector3(-t, 0f, 1f).normalized *radius);
// create 20 triangles of the icosahedron
List <TriangleIndices> faces = new List <TriangleIndices>();
// 5 faces around point 0
faces.Add(new TriangleIndices(0, 11, 5));
faces.Add(new TriangleIndices(0, 5, 1));
faces.Add(new TriangleIndices(0, 1, 7));
faces.Add(new TriangleIndices(0, 7, 10));
faces.Add(new TriangleIndices(0, 10, 11));
// 5 adjacent faces
faces.Add(new TriangleIndices(1, 5, 9));
faces.Add(new TriangleIndices(5, 11, 4));
faces.Add(new TriangleIndices(11, 10, 2));
faces.Add(new TriangleIndices(10, 7, 6));
faces.Add(new TriangleIndices(7, 1, 8));
// 5 faces around point 3
faces.Add(new TriangleIndices(3, 9, 4));
faces.Add(new TriangleIndices(3, 4, 2));
faces.Add(new TriangleIndices(3, 2, 6));
faces.Add(new TriangleIndices(3, 6, 8));
faces.Add(new TriangleIndices(3, 8, 9));
// 5 adjacent faces
faces.Add(new TriangleIndices(4, 9, 5));
faces.Add(new TriangleIndices(2, 4, 11));
faces.Add(new TriangleIndices(6, 2, 10));
faces.Add(new TriangleIndices(8, 6, 7));
faces.Add(new TriangleIndices(9, 8, 1));
// refine triangles
for (int i = 0; i < recursionLevel; i++)
{
List <TriangleIndices> faces2 = new List <TriangleIndices>();
foreach (var tri in faces)
{
// replace triangle by 4 triangles
int a = getMiddlePoint(tri.v1, tri.v2, ref vertList, ref middlePointIndexCache, radius);
int b = getMiddlePoint(tri.v2, tri.v3, ref vertList, ref middlePointIndexCache, radius);
int c = getMiddlePoint(tri.v3, tri.v1, ref vertList, ref middlePointIndexCache, radius);
faces2.Add(new TriangleIndices(tri.v1, a, c));
faces2.Add(new TriangleIndices(tri.v2, b, a));
faces2.Add(new TriangleIndices(tri.v3, c, b));
faces2.Add(new TriangleIndices(a, b, c));
}
faces = faces2;
}
Vector3[] normals = new Vector3[vertList.Count];
for (int i = 0; i < normals.Length; i++)
{
normals[i] = vertList[i].normalized;
}
if (celestialBody != null)
{
for (int i = 0; i < vertList.Count; i++)
{
Vector3d rotVert = Tools.RotateY(vertList[i], .5 * Math.PI);
float value = (float)(height + celestialBody.pqsController.GetSurfaceHeight(rotVert));
vertList[i] *= value;
}
}
mesh.vertices = vertList.ToArray();
List <int> triList = new List <int>();
for (int i = 0; i < faces.Count; i++)
{
triList.Add(faces[i].v1);
triList.Add(faces[i].v2);
triList.Add(faces[i].v3);
}
mesh.triangles = triList.ToArray();
float invPi2 = 1 / (2 * Mathf.PI);
float invPi = 1 / (Mathf.PI);
List <Vector2> uvList = new List <Vector2>();
for (int i = 0; i < vertList.Count; i++)
{
Vector2 uv = new Vector2();
Vector3 normal = vertList[i].normalized;
uv.x = 0.5f + invPi2 * Mathf.Atan2(normal.z, normal.x);
uv.y = 0.5f - invPi * Mathf.Asin(normal.y);
uvList.Add(uv);
}
mesh.uv = uvList.ToArray();
mesh.normals = normals;
Tools.CalculateMeshTangents(mesh);
mesh.RecalculateBounds();
mesh.Optimize();
}
