public GeodesicGrid(IIcosahedralGridOptions options)
{
var icosahedralGrid = new IcosahedralGrid(options);
var icosahedralFaces = icosahedralGrid.Faces;
var icosahedralEdges = icosahedralFaces.SelectMany(face => face.Edges).Distinct().ToList();
var icosahedralVertices = icosahedralFaces.SelectMany(face => face.Vertices).Distinct().ToList();
var icosahedralFaceToGeodesicVertexMap = CreateGeodesicVertices(icosahedralFaces);
var icosahedralEdgeToGeodesicEdgeMap = CreateGeodesicEdges(icosahedralEdges, icosahedralFaceToGeodesicVertexMap);
var icosahedralVertexToGeodesicFaceMap = CreateGeodesicFaces(icosahedralVertices, icosahedralEdgeToGeodesicEdgeMap);
Faces = icosahedralVertexToGeodesicFaceMap.Values.ToList();
}
// The process is this: create a basic 20-face icosahedron, and break all its edges in two, introducing new
// vertices at each break. Then make a pass over each face, subdividing it into four new lil' triangles.
public IcosahedralGrid(IIcosahedralGridOptions options)
{
var targetAngularResolution = options.Resolution / options.Radius;
// Create our basic icosahedron
CreateIcosahedron();
var currentAngularResolution = 1 / Mathf.Sin(2 * Mathf.PI / 5);
while (currentAngularResolution > targetAngularResolution)
{
// Break all the edges in two and create midpoints between each new pair.
var edgeSubdivision = new EdgeSubdivision(Edges, Vertices);
Edges = edgeSubdivision.Edges;
Vertices = edgeSubdivision.Vertices;
// Break all the faces into four, generating some new edges in the process as well.
var faceSubdivision = new FaceSubdivision(Faces, Edges, Vertices);
Faces = faceSubdivision.Faces;
Edges = faceSubdivision.Edges;
Vertices = faceSubdivision.Vertices;
currentAngularResolution /= 2;
}
}
