import math
from pixel import Pixel

COLOR_A = (0.0, 0.7, 0.8)
COLOR_B = (0.8, 0.0, 0.7)

HEIGHT = 6.0
RADIUS = 1.

def distance(a: tuple, b: tuple) -> float:
	if len(a) != len(b):
		raise TypeError("Mismatching dimentional vector passed")

	dist = 0
	for i in range(len(a)):
		d = b[i] - a[i]
		dist += d * d

	return dist ** 0.5

def get_col(uv: tuple) -> tuple:
	uv = tuple(math.floor(x) for x in uv)
	return COLOR_A if ((uv[0] + uv[1]) % 2) == 0.0 else COLOR_B

def main(pixel: Pixel, resolution: tuple, frag_coord: tuple, time: float): # https://www.shadertoy.com/view/lsyyDK
	uv = [ x * HEIGHT for x in (frag_coord[0] / resolution[1], frag_coord[1] / resolution[1]) ]

	direction = int(time) % 2
	shift = math.floor(uv[1 - direction])
	shift = 2.0 * (shift % 2) - 1.0
	uv[direction] += shift * time

	dist = 1.0 - distance((0.0, 0.0), tuple((x % 1.0) - 0.5 for x in uv)) / RADIUS

	col = tuple(x * dist for x in get_col(uv))

	pixel.background_color.set( *col )