#!/usr/bin/env python3

import sys

def usage():
    print("usage: Kr Kg Kb full|limited")
    print("examples:")
    print("  create_matrix.py 0.2126 0.7152 0.0722 full")
    print("  create_matrix.py 0.2126 0.7152 0.0722 limited")
    exit(1)

def main(argv):
    if len(argv) != 5:
        usage()

    Kr = float(sys.argv[1])
    Kg = float(sys.argv[2])
    Kb = float(sys.argv[3])
    color_range = sys.argv[4]
    luma_offset = 0.0
    transform_range = 1.0

    if color_range == "full":
        pass
    elif color_range == "limited":
        transform_range = (235.0 - 16.0) / 255.0
        luma_offset = 16.0 / 255.0

    matrix = [
        [Kr,                        Kg,                        Kb],
        [-0.5 * (Kr / (1.0 - Kb)), -0.5 * (Kg / (1.0 - Kb)),  0.5],
        [0.5,                      -0.5 * (Kg / (1.0 - Kr)), -0.5 * (Kb / (1.0 -Kr))],
        [0.0,                       0.5,                      0.5]
    ]

    # Transform from row major to column major for glsl
    print("%f, %f, %f, %f" % (matrix[0][0] * transform_range, matrix[1][0] * transform_range, matrix[2][0] * transform_range, 0.0))
    print("%f, %f, %f, %f" % (matrix[0][1] * transform_range, matrix[1][1] * transform_range, matrix[2][1] * transform_range, 0.0))
    print("%f, %f, %f, %f" % (matrix[0][2] * transform_range, matrix[1][2] * transform_range, matrix[2][2] * transform_range, 0.0))
    print("%f, %f, %f, %f" % (matrix[3][0] + luma_offset,     matrix[3][1],                   matrix[3][2],                   1.0))

main(sys.argv)