def METHOD_NAME(self, x, y, v):
    '''Set a vertex point is a certain value
    :Parameters:
        `x` : int
           x-vertex
        `y` : int
           y-vertex
        `v` : (int, int, int)
            tuple value for the vertex
    '''
    idx = (x * (self.grid_size.y+1) + y) * 3
    self.vertex_list.vertices[idx] = v[0]
    self.vertex_list.vertices[idx+1] = v[1]
    self.vertex_list.vertices[idx+2] = v[2]