From: Ian Jackson <ijackson@chiark.greenend.org.uk>
Date: Tue, 7 Nov 2017 12:38:37 +0000 (+0000)
Subject: introduce Moebius.details()
X-Git-Url: https://www.chiark.greenend.org.uk/ucgi/~ian/git?a=commitdiff_plain;h=25170d3ca5759a4e6fb3ff26496ed741f8a9cbdb;p=moebius3.git

introduce Moebius.details()

nfc because no callers yet

Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>
---

diff --git a/moebius.py b/moebius.py
index 6d0d2bc..367243c 100644
--- a/moebius.py
+++ b/moebius.py
@@ -174,3 +174,17 @@ class Moebius():
     return m.h.point_offset(offset=
                             offset if w <= m.nt else -offset,
                             **m._vw2tiu_kw(v,w))
+
+  def details(m, v, w):
+    '''
+    returns tuple of 4 vectors:
+           - point location
+           - normal (+ve is in the +ve y direction at iu=t=0) unit vector
+           - along extent   (towrds +ve v)                    unit vector
+           - along traverse (towards +ve w)                   unit vector
+    '''
+    p, normal, vec_v, vec_w = m.h.dtails(**m._vw2tiu_kw(v,w))
+    if w > m.nt:
+      normal = -normal
+      vec_w  = -vec_w
+    return p, normal, vec_v, vec_w