from libs import *

# https://iquilezles.org/articles/intersectors/
def intersect_tri(ro, rd, verts):
    e1 = verts[1] - verts[0]
    e2 = verts[2] - verts[0]
    to = ro - verts[0]
    n = np.cross(e1, e2)
    q = np.cross(to, rd)
    d = 1.0 / np.dot(rd, n)
    u = d * np.dot(-q, e2)
    v = d * np.dot(q, e1)
    t = d * np.dot(-n, to)
    if u > 0.0 and v > 0.0 and u + v < 1.0 and t > 1e-3:
        return t

def intersect_box(ro, rd, c, s):
    m = 1 / rd
    n = m * (ro - c)
    k = np.abs(m) * s
    tn = np.max(-n - k)
    tf = np.min(-n + k)
    if tf > tn and tf > 0:
        return tn, tf
    else:
        return None, None