import numpy as np

# h = 0..359
# s = 0..255
# v = 0..511 (values above 255 add white channel)
def hsv2rgbw(h, s, v):

    h %= 360

    v_ = min(255, v)

    # C = 0..255
    C = (v_ * s) // 256

    h_ = 128 * h // 60

    # X = 0..255
    X = C * (128 - abs(h_ % 256 - 128)) // 128

    if h < 60:
        r, g, b = C, X, 0
    elif h < 120:
        r, g, b = X, C, 0
    elif h < 180:
        r, g, b = 0, C, X
    elif h < 240:
        r, g, b = 0, X, C
    elif h < 300:
        r, g, b = X, 0, C
    else:
        r, g, b = C, 0, X

    m = v_ - C
    r += m
    g += m
    b += m

    if v >= 256:
        w = v - 255
    else:
        w = 0

    return np.array([r, g, b, w])