def has_vertex(t, tri, vertex):
    """
    Whether or not a triangle contains a specific vertex.

    :param t: List of triangle indices in the mesh. Size (n, 3) where n is the number of triangles.
    :param tri: Triangle index.
    :param vertex: Vertex index.
    :returns: True if the triangle contains the vertex, otherwise False.
    """
    for i in range(3):
        if t[tri][i] == vertex:
            return True
    return False