[SOLVED] Custom UV vertex Data with Duplicate Points on Facets

[Pryme8]

So I am getting ready to do dynamic LOD terrain by using chunking and T-Junctions and so I was making the function to create the mesh data.
I am fully aware of http://babylonjsguide.github.io/advanced/Custom but in it, there is nothing that covers the thing I need to know because its only shows building one facet.

http://playground.babylonjs.com/#IJTGJ3

So I have my first variance of the 8 T-Junctions and now I am wondering how I do the uv set up because all of the facets share the 0 position/point.  
do I just repeat the uv data on that point? 

so for example if I was just gonna do the first two facets:
var uv = [
//facet 0
0,1,
0.5, 0.5,
0.5, 1,
//facet 1
0.5, 0.5,
1, 1,
0.5, 1
];

Notice how I use 0.5, 0.5 twice?  This will be repeated for every facet because they all share the 0 point?  I figured this is correct but before I make assumptions It would be worth asking!

Update/EDIT ***
just need to know if this is correct, I guess I could write up a quick shader to show UV positions but I'm being lazy and want to go to bed.

    var mesh = new BABYLON.Mesh('tPlane', scene);
    var vData = new BABYLON.VertexData();
    var hs = size*0.5;
    var points = 
    [
        0,0,0,          //0
        -1*hs,0,1*hs,   //1
        0,0,1*hs,       //2
        1*hs,0,1*hs,    //3
        1*hs,0,0,       //4
        1*hs,0,-1*hs,   //5
        0,0,-1*hs,      //6
        -1*hs,0,-1*hs,  //7
        -1*hs,0,0       //8

    ];
    var indices = 
    [
        1,0,2,
        0,3,2,
        0,4,3,
        0,5,4,
        0,6,5,
        7,6,0,
        8,7,0,
        1,8,0
    ];

    var normals = [];

    BABYLON.VertexData.ComputeNormals(points, indices, normals);
    
    var uv =
    [
        0,1, 0.5, 0.5, 0.5, 1,
        0.5, 0.5, 1, 1, 0.5, 1,
        0.5, 0.5, 1, 0.5, 1, 1,
        0.5, 0.5, 1, 0, 1, 0.5,
        0.5, 0.5, 0.5, 0, 1, 0,
        0, 0, 0, 0.5, 0.5, 0.5,
        0, 0.5, 0, 0, 0.5, 0.5,
        0, 1, 0, 0.5, 0.5, 0.5
    ];

    vData.positions = points;
    vData.indices = indices;
    vData.normals = normals;
    vData.uv = uv;

    vData.applyToMesh(mesh);

http://playground.babylonjs.com/#IJTGJ3#2

[JohnK]

Nearly there

1) Each point has to be matched to one position on the image, so 8 points then 8 uv pairs

2) You missed the line vData.uv = uv from the playground  BUT

3) vData.uvs  needs the s

Hope this PG helps http://playground.babylonjs.com/#IJTGJ3#3

If you have a plane with left front corner at (p, q) and width w and height h, the for any point (x, z) in the plane for a straight mapping of an image onto the plane

the uv pair for (x, z) is ( (x - p)/w, (z - q)/h )

Of course you can mess around with the uvs if you want.

[Pryme8]

thank you john, I have struggled with a equation to do UVs and "the uv pair for (x, z) is ( (x - p)/w, (z - q)/h )" makes a lot of since now thank you!

I thought it was per facet but now I understand its per position point!  Your a boss!