I'm probably doing this really inefficiently, but I'm having trouble recalculating the triangles array of a mesh I'm deleting vertices from. I can delete the vertices without issue (I think), but I'm getting hung up on the triangles array.

What I have so far works for deleting vertices, but it overflows the length of the new triangles array I'm initializing.

    // First pass; null out any verts that are below the ocean in the vertex array 
    vertices = mesh.vertices; 
    var dist : float = 0.0; 
    var numberOfVerticesLeft : int = vertices.length; 
    print ("original vertices array length is " + vertices.length); 

    for (var vertex in vertices) 
    { 
        dist = Vector3.Distance(Vector3.zero, vertex); 
        if (dist < planetRadius) 
        { 
            numberOfVerticesLeft--; 
            vertex = Vector3.zero; 
        } 
    } 
    print("New vertices array will be this long: " + numberOfVerticesLeft); 


    // Second pass; build up the new vertex array only from the good values 
    var newVerts = new Vector3[numberOfVerticesLeft]; 
    i = 0; 
    for (vertex in vertices) 
    { 
        if (vertex != Vector3.zero) 
        { 
            newVerts[i] = vertex; 
            i++; 
        } 
    } 
    print("Added " + i + " elements to new vertex array"); 


    // Third pass; loop through the triangle array to discover 
   // which elements point to zeroed vertices, then set 'em to -1 
   var triangles = mesh.triangles; 
   var numberOfTrianglesLeft : int = triangles.length; 
    print ("original triangles array length is " + triangles.length); 

    for (var tri in mesh.triangles) 
    { 
        if (vertices[tri] == Vector3.zero) 
        { 
            numberOfTrianglesLeft--; 
            tri = -1; 
        } 
    } 
    print("New triangles array will be this long: " + numberOfTrianglesLeft); 


    // Fourth pass; build up the new triangle array only from the good values 
    var newTriangles = new int[numberOfTrianglesLeft]; 
    i = 0; 
    for (tri in triangles) 
    { 
        if (tri != -1) 
        { 
            newTriangles[i] = tri; 
            i++; 
            print("Added " + i + " elements to new triangles array"); 
        } 
    } 
    // print("Added " + i + "elements to new triangles array"); 

    mesh.triangles = newTriangles; 
    mesh.vertices = newVerts;