def normalize_min_max(a, vmin: float = None, vmax: float = None, gamma: float = 1.0):
    """normalize an array between 0 - 1, clipped to (vmin, vmax)"""
    vmin = np.min(a) if vmin is None else vmin
    vmax = np.max(a) if vmax is None else vmax

    if vmax <= vmin:
        return np.zeros(a.size)

    transform = np.clip((a - vmin) / (vmax - vmin), 0, 1)
    if gamma == 1.0:
        return transform
    return transform ** gamma

xs = np.linspace(0, 4 * np.pi, 100)
ys = np.sin(xs)
data = np.column_stack([xs, ys])

ys_scaled = normalize_min_max(ys)
geometry.texcoords = pygfx.Buffer(ys_scaled.astype(np.float32))

material.color_mode = "vertex_map"
material.map = cmap_lib.Colormap("seismic").to_pygfx()