def find_intersections(Cs, Qs, plucker, ray_ind, planes, sel):
'''
Plucker coords make the collision check quite fast, requiring few ops.
Cs, Qs, plucker: Canonical and Plucker representations of set of rays
ray_ind: Specific inds of the rays/ray triangle that's being intersected
plane: Plane describing the ray triangle
sel: Subset of rays to check
'''
N = Cs.shape[0]
pl1a, pl1b = plucker[ray_ind], plucker[ray_ind + 1]
plane = planes[ray_ind]
intersects = empty(N, np.int64)
ps1 = empty((N, 3), Cs.dtype)
us = empty((N, 3), Cs.dtype)
j = 0
pl2a = plucker.T[:, sel]
pl2b = plucker.T[:, sel + 1]
skews = np.sign( Geom.check_plucker(pl1a, pl2a) ) \
+ np.sign( Geom.check_plucker(pl1a, pl2b) ) \
+ np.sign( Geom.check_plucker(pl1b, pl2a) ) \
+ np.sign( Geom.check_plucker(pl1b, pl2b) )
for s, i in enumerate(sel):
if abs(skews[s]) == 4:
# Both rays skew on the same side of the other 2 rays
continue
# Find the intersection of the rays with the plane
c1, c2 = Cs[i], Cs[i + 1]
q1, q2 = Qs[i], Qs[i + 1]
t1, int1 = Geom.intersect_line_plane(c1, q1, plane)
t2, int2 = Geom.intersect_line_plane(c2, q2, plane)
if not int1 or not int2:
continue
intersects[j] = i
for k in range(3):
ps1[j, k] = c1[k] + t1 * q1[k]
us[j, k] = (c2[k] + t2 * q2[k]) - ps1[j, k]
# ps2[j, k] = c2[k] + t2*q2[k]
j += 1
return ps1[:j], us[:j], intersects[:j]
def find_intersections(Cs, Qs, plucker, ray_ind, plane, sel):
'''
Cs, Qs, plucker: Canonical and Plucker representations of set of rays
ray_ind: Specific inds of the rays/ray triangle that's being intersected
plane: Plane describing the ray triangle
sel: Subset of rays to check
'''
N = Cs.shape[0]
pl1 = plucker[ray_ind:ray_ind + 2]
intersects = empty(N, np.int64)
ps = empty((N, 3), Cs.dtype)
us = empty((N, 3), Cs.dtype)
j = 0
for k, i in enumerate(sel):
pl2 = plucker[i:i + 2]
skew = empty(4, np.int16)
for a in range(2):
for b in range(2):
skew[2 * a + b] = np.sign(Geom.check_plucker(pl1[a], pl2[b]))
if abs(skew.sum()) == 4:
# Both rays skew on the same side of the other 2 rays
continue
# Find the intersection of the rays with the plane
c1, c2 = Cs[i], Cs[i + 1]
q1, q2 = Qs[i], Qs[i + 1]
t1, int1 = Geom.intersect_line_plane(c1, q1, plane)
t2, int2 = Geom.intersect_line_plane(c2, q2, plane)
if not int1 or not int2:
continue
intersects[j] = k
ps[j] = c1 + t1 * q1
us[j] = (c2 + t2 * q2) - ps[j]
j += 1
return ps[:j], us[:j], intersects[:j]