Hexagon mesh subdivided into triangles

Edit: after some editing I have fixed the bug of the incomplete hexagons.

Hi guys,

I am trying to create a hexagon mesh where each hexagon is subdivided into 6 triangles. I want to be able to texture each triangle with an individual texture, however have run into a snag creating the mesh. At the moment I have written some code that creates hexagons however the results are pretty far off from what I want to achieve.

After some messing around I have managed to fix a bug causing the hexagons to appear incomplete. Now I need to solve how to correctly place the hexagons in a grid formation. The code for the offset of each hexagon is:

 float height = _radius * 2;
 float width = Mathf.Sqrt(3)/2 * height;
 float horizon = height*3/4;
 float vertical = width;
 
 
 Vector2 sO = new Vector2(x*horizon, z*vertical);
 Vector2 sOffset = new Vector2(_startCenter.x + (sO.x + (z%2==0 ? 0 : (sO.x/2))), (_startCenter.z + sO.y));

Complete code below:

 private void GenerateGrid()
 {
     //Constants for hexagon calculations
     float height = _radius * 2;
     float width = Mathf.Sqrt(3)/2 * height;
     float horizon = height*3/4;
     float vertical = width;
 
     //Arrays for hexagon vertices (tG), nomalization and uv
     Vector3[] tG = new Vector3[_totalHex*18];
     Vector3[] norm = new Vector3[_totalHex*18];
     Vector2[] uv = new Vector2[_totalHex*18];
         
     for(int z = 0; z < _size.y; z++)
     {
         for(int x = 0; x < _size.x; x++)
         {    
             //Sets variables for hexagon creation
             int y = 0;
             Vector2 sO = new Vector2(x*horizon, z*vertical);
             Vector2 sOffset = new Vector2(_startCenter.x + (sO.x + (z%2==0 ? 0 : (sO.x/2))), (_startCenter.z + sO.y));
             for(int i = 0; i < 18; i++)
             {
                 //Iterates y every third iteration of i
                 y += ((i+1)%3 == 0 ? 1  : 0); 
 
                 //sets y to 0 to close the hexagon and the end
                 if((i+1)%18 == 0)
                 {
                     y = 0;
                 }
                 ////
 
                 //Every third (including 0) should be the center vertex (c), all others should be the vertexes of the outer ring (n)
                 //The iteration on hexagon one should be [c, n0, n1, c, n1, n2, c, n2, n3, c, n3, n4, c, n4, n5, c, n5, n0]
                 tG[((z*_size.x+x)*18)+i] = (i%3 == 0 ? new Vector3(sOffset.x, _startCenter.y, sOffset.y)
                                                 : new Vector3(sOffset.x + (_radius * Mathf.Cos(2*Mathf.PI * (y+0.5f)/6)), 
                                                   _startCenter.y,
                                                  sOffset.y + (_radius * Mathf.Sin(2*Mathf.PI * (y+0.5f)/6))));
 
                 //uv[((z*_size.x+x)*18)+i] = new Vector2(x*i, y*i);
                 norm[((z*_size.x+x)*18)+i] = Vector3.up;
             }
         }
     }
 
     //sets arrays for mesh (_key = triangles)
     _worldVertices = tG;
     _normals = norm;
     _key = Enumerable.Range(0, _totalHex*18).ToArray();
 }

I hope I have made the question easily understandable and someone is able to tell me what I'm doing wrong and how I might fix it. Possibly tell me a less contrived way of doing this. Finally, I apologize if this question is cluttered.

Bonus question: How would I UV map these hexagons?