import numpy as np


def sperical2equirec(theta, phi, img_w, img_h):
    u = np.deg2rad(theta) / (2 * np.pi)
    v = np.deg2rad(phi) / np.pi

    x = u * img_w
    y = v * img_h
    return x, y


def equirec2spherical(x, y, img_w, img_h):
    # Normalize coordinates
    u = x / img_w
    v = y / img_h

    # Calculate spherical coordinates from normalized coordinates
    # theta is horizontal angle, phi is polar angle
    theta = u * 2 * np.pi
    phi = v * np.pi

    return np.rad2deg(theta), np.rad2deg(phi)


def get_circle(radius):
    """ helper function returns circle to x, y coordinates"""
    theta = np.linspace(0, 2 * np.pi, 100)
    x = radius * np.cos(theta)
    y = radius * np.sin(theta)
    return np.array(x), np.array(y)