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• Create a regular n-hedron (a solid where every face is the same size). I use an icosahedron because it's the solid with the greatest number of faces where every face is the same size. (There's a proof for that somewhere out there. Feel free to Google if you're really curious.) This will give you a sphere where nearly every face is the same size, making texturing a little easier.

• Create a regular n-hedron (a solid where every face is the same size and every edge is the same length). I use an icosahedron because it's the regular solid with the greatest number of faces. (There's a proof for that somewhere out there. Feel free to Google if you're really curious.) This will give you a sphere where nearly every face is the same size, making texturing a little easier.

EDIT

I just noticed that you're trying to create a lat/long-type sphere rather than a geosphere. I'll see what I can dig up, but unless you have a particular reason for doing this - you're drawing this wireframe and want a particular aesthetic - than a geosphere is a lot more texture friendly.

public static class GeometryProvider
{

    private static int GetMidpointIndex(Dictionary<string, int> midpointIndices, List<Vector3> vertices, int i0, int i1)
    {

        var edgeKey = string.Format("{0}_{1}", Math.Min(i0, i1), Math.Max(i0, i1));

        var midpointIndex = -1;

        if (!midpointIndices.TryGetValue(edgeKey, out midpointIndex))
        {
            var v0 = vertices[i0];
            var v1 = vertices[i1];

            var midpoint = (v0 + v1) / 2f;

            if (vertices.Contains(midpoint))
                midpointIndex = vertices.IndexOf(midpoint);
            else
            {
                midpointIndex = vertices.Count;
                vertices.Add(midpoint);
                midpointIndices.Add(edgeKey, midpointIndex);
            }
        }


        return midpointIndex;

    }

    /// <remarks>
    ///      i0
    ///     /  \
    ///    m02-m01
    ///   /  \ /  \
    /// i2---m12---i1
    /// </remarks>
    /// <param name="vectors"></param>
    /// <param name="indices"></param>
    public static void Subdivide(List<Vector3> vectors, List<int> indices, bool removeSourceTriangles)
    {
        var midpointIndices = new Dictionary<string, int>();

        var newIndices = new List<int>(indices.Count * 4);

        if (!removeSourceTriangles)
            newIndices.AddRange(indices);

        for (var i = 0; i < indices.Count - 2; i += 3)
        {
            var i0 = indices[i];
            var i1 = indices[i + 1];
            var i2 = indices[i + 2];

            var m01 = GetMidpointIndex(midpointIndices, vectors, i0, i1);
            var m12 = GetMidpointIndex(midpointIndices, vectors, i1, i2);
            var m02 = GetMidpointIndex(midpointIndices, vectors, i2, i0);

            newIndices.AddRange(
                new[] {
                    i0,m01,m02
                    ,
                    i1,m12,m01
                    ,
                    i2,m02,m12
                    ,
                    m02,m01,m12
                }
                );

        }

        indices.Clear();
        indices.AddRange(newIndices);
    }

    /// <summary>
    /// create a regular icosahedron (20-sided polyhedron)
    /// </summary>
    /// <param name="primitiveType"></param>
    /// <param name="size"></param>
    /// <param name="vertices"></param>
    /// <param name="indices"></param>
    /// <remarks>
    /// You can create this programmatically instead of using the given vertex 
    /// and index list, but it's kind of a pain and rather pointless beyond a 
    /// learning exercise.
    /// </remarks>

    public static void Icosahedron(List<Vector3> vertices, List<int> indices)
    {

        indices.AddRange(
            new int[]
            {
                0,4,1,
                0,9,4,
                9,5,4,
                4,5,8,
                4,8,1,
                8,10,1,
                8,3,10,
                5,3,8,
                5,2,3,
                2,7,3,
                7,10,3,
                7,6,10,
                7,11,6,
                11,0,6,
                0,1,6,
                6,1,10,
                9,0,11,
                9,11,2,
                9,2,5,
                7,2,11 
            }
            .Select(i => i + vertices.Count)
        );

        var X = 0.525731112119133606f;
        var Z = 0.850650808352039932f;

        vertices.AddRange(
            new[] 
            {
                new Vector3(-X, 0f, Z),
                new Vector3(X, 0f, Z),
                new Vector3(-X, 0f, -Z),
                new Vector3(X, 0f, -Z),
                new Vector3(0f, Z, X),
                new Vector3(0f, Z, -X),
                new Vector3(0f, -Z, X),
                new Vector3(0f, -Z, -X),
                new Vector3(Z, X, 0f),
                new Vector3(-Z, X, 0f),
                new Vector3(Z, -X, 0f),
                new Vector3(-Z, -X, 0f) 
            }
        );


    }



}

public static class GeometryProvider
{

    private static int GetMidpointIndex(Dictionary<string, int> midpointIndices, List<Vector3> vertices, int i0, int i1)
    {

        var edgeKey = string.Format("{0}_{1}", Math.Min(i0, i1), Math.Max(i0, i1));

        var midpointIndex = -1;

        if (!midpointIndices.TryGetValue(edgeKey, out midpointIndex))
        {
            var v0 = vertices[i0];
            var v1 = vertices[i1];

            var midpoint = (v0 + v1) / 2f;

            if (vertices.Contains(midpoint))
                midpointIndex = vertices.IndexOf(midpoint);
            else
            {
                midpointIndex = vertices.Count;
                vertices.Add(midpoint);
                midpointIndices.Add(edgeKey, midpointIndex);
            }
        }


        return midpointIndex;

    }

    /// <remarks>
    ///      i0
    ///     /  \
    ///    m02-m01
    ///   /  \ /  \
    /// i2---m12---i1
    /// </remarks>
    /// <param name="vectors"></param>
    /// <param name="indices"></param>
    public static void Subdivide(List<Vector3> vectors, List<int> indices, bool removeSourceTriangles)
    {
        var midpointIndices = new Dictionary<string, int>();

        var newIndices = new List<int>(indices.Count * 4);

        if (!removeSourceTriangles)
            newIndices.AddRange(indices);

        for (var i = 0; i < indices.Count - 2; i += 3)
        {
            var i0 = indices[i];
            var i1 = indices[i + 1];
            var i2 = indices[i + 2];

            var m01 = GetMidpointIndex(midpointIndices, vectors, i0, i1);
            var m12 = GetMidpointIndex(midpointIndices, vectors, i1, i2);
            var m02 = GetMidpointIndex(midpointIndices, vectors, i2, i0);

            newIndices.AddRange(
                new[] {
                    i0,m01,m02
                    ,
                    i1,m12,m01
                    ,
                    i2,m02,m12
                    ,
                    m02,m01,m12
                }
                );

        }

        indices.Clear();
        indices.AddRange(newIndices);
    }

    /// <summary>
    /// create a regular icosahedron (20-sided polyhedron)
    /// </summary>
    /// <param name="primitiveType"></param>
    /// <param name="size"></param>
    /// <param name="vertices"></param>
    /// <param name="indices"></param>
    /// <remarks>
    /// You can create this programmatically instead of using the given vertex 
    /// and index list, but it's kind of a pain and rather pointless beyond a 
    /// learning exercise.
    /// </remarks>

    /// note: icosahedron definition may have come from the OpenGL red book. I don't recall where I found it. 
    public static void Icosahedron(List<Vector3> vertices, List<int> indices)
    {

        indices.AddRange(
            new int[]
            {
                0,4,1,
                0,9,4,
                9,5,4,
                4,5,8,
                4,8,1,
                8,10,1,
                8,3,10,
                5,3,8,
                5,2,3,
                2,7,3,
                7,10,3,
                7,6,10,
                7,11,6,
                11,0,6,
                0,1,6,
                6,1,10,
                9,0,11,
                9,11,2,
                9,2,5,
                7,2,11 
            }
            .Select(i => i + vertices.Count)
        );

        var X = 0.525731112119133606f;
        var Z = 0.850650808352039932f;

        vertices.AddRange(
            new[] 
            {
                new Vector3(-X, 0f, Z),
                new Vector3(X, 0f, Z),
                new Vector3(-X, 0f, -Z),
                new Vector3(X, 0f, -Z),
                new Vector3(0f, Z, X),
                new Vector3(0f, Z, -X),
                new Vector3(0f, -Z, X),
                new Vector3(0f, -Z, -X),
                new Vector3(Z, X, 0f),
                new Vector3(-Z, X, 0f),
                new Vector3(Z, -X, 0f),
                new Vector3(-Z, -X, 0f) 
            }
        );


    }



}