From dbb01513e9a001ea8a8e833566b77c2ab773ef47 Mon Sep 17 00:00:00 2001
From: Paul McCarthy <pauldmccarthy@gmail.com>
Date: Sat, 9 Nov 2019 06:11:29 +0000
Subject: [PATCH] BF: Make mesh.needsFixing a little more robust? To my
knowledge there's no methoed to do this which is both fast and foolproof
---
fsl/data/mesh.py | 24 ++++++++++++++----------
1 file changed, 14 insertions(+), 10 deletions(-)
diff --git a/fsl/data/mesh.py b/fsl/data/mesh.py
index c15e49ced..8d05af196 100644
--- a/fsl/data/mesh.py
+++ b/fsl/data/mesh.py
@@ -758,15 +758,19 @@ def needsFixing(vertices, indices, fnormals, loBounds, hiBounds):
ivert = np.argmin(dists)
vert = vertices[ivert]
- # Pick a triangle that
- # this vertex is in and
- # ges its face normal
- itri = np.where(indices == ivert)[0][0]
- n = fnormals[itri, :]
+ # Get all the triangles
+ # that this vertex is in
+ # and their face normals
+ itris = np.where(indices == ivert)[0]
+ norms = fnormals[itris, :]
- # Make sure the angle between the
+ # Calculate the angle between each
# normal, and a vector from the
- # vertex to the camera is positive
- # If it isn't, we need to flip the
- # triangle winding order.
- return np.dot(n, affine.normalise(camera - vert)) < 0
+ # vertex to the camera. If more than
+ # 50% of the angles are negative
+ # (== more than 90 degrees == the
+ # face is facing away from the
+ # camera), assume that we need to
+ # flip the triangle winding order.
+ angles = np.dot(norms, affine.normalise(camera - vert))
+ return ((angles > 0).sum() / len(itris)) < 0.5
--
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