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| author | Eugeniy Mikhailov <evgmik@gmail.com> | 2013-02-28 14:59:55 -0500 |
|---|---|---|
| committer | Eugeniy Mikhailov <evgmik@gmail.com> | 2013-02-28 14:59:55 -0500 |
| commit | e4360a48435cc762855d356b208b5544e6f40c4b (patch) | |
| tree | 71c6c83c247cb07495265b93ec062eefc3e928a8 /beam_tracing/python/beam2FaceDistance.py | |
| parent | a08ed173692ce16b79002733003049ec32a02485 (diff) | |
| download | wgmr-e4360a48435cc762855d356b208b5544e6f40c4b.tar.gz wgmr-e4360a48435cc762855d356b208b5544e6f40c4b.zip | |
Added python version of mode-matching code by Bain Bronner
Diffstat (limited to 'beam_tracing/python/beam2FaceDistance.py')
| -rw-r--r-- | beam_tracing/python/beam2FaceDistance.py | 53 |
1 files changed, 53 insertions, 0 deletions
diff --git a/beam_tracing/python/beam2FaceDistance.py b/beam_tracing/python/beam2FaceDistance.py new file mode 100644 index 0000000..8aeedec --- /dev/null +++ b/beam_tracing/python/beam2FaceDistance.py @@ -0,0 +1,53 @@ +import numpy as np
+
+def beam2FaceDistance(beam, face):
+# return distance to face if beam hits it or infinity otherwise
+# for beams and faces structure description see face_beam_interaction.m
+
+ # default return values for the case when beam misses the face
+ isFaceHit = False
+ hitPosition = [float('NaN'), float('NaN')]
+ hitDistance = float('Inf')
+
+ k = beam.k
+ # face direction or kf
+ kf = face.vertex2 - face.vertex1 # not a unit vector
+
+ # simple check for intersection of two vectors
+ # if beam are parallel no intersection is possible
+ # we do this via cross product calculation
+
+ angleTolerance = 1e-14;
+ if abs(np.cross(k, kf)) <= angleTolerance:
+ # beams misses face
+ return [hitDistance, hitPosition, isFaceHit]
+
+ # let's find the intersection of lines passing through face and light beam
+ # we introduce parameters tb and tf
+ # which define distance (in arb. units) along k vectors
+ # we are solving
+ # xb_o+ k_x*tb = v1_x+ kf_x*tf
+ # yb_o+ k_y*tb = v1_y+ kf_y*tf
+ # A*t = B
+ A = np.array([[k[0], -kf[0]],\
+ [k[1], -kf[1]]])
+ B = np.array([[face.vertex1[0] - beam.origin[0]],\
+ [face.vertex1[1] - beam.origin[1]]])
+ A = np.linalg.inv(A)
+ t = np.dot(A, B)
+ tb = t[0]
+ tf = t[1]
+
+ # beam intersects face only if 0<=tf<=1 and tb>=0
+ if 0 <= tf and tf <= 1 and tb >= angleTolerance:
+ # intersection, beam hits the face
+ isFaceHit = True
+ else:
+ # beam misses the face
+ return [hitDistance, hitPosition, isFaceHit]
+
+ # calculating hit position
+ hitPosition = face.vertex1 + kf * tf
+ hitDistance = tb # distance along the light beam
+
+ return [hitDistance, hitPosition, isFaceHit]
\ No newline at end of file |