From 3c0a0d7ade365f46e3a3d765ac235806981f317c Mon Sep 17 00:00:00 2001
From: Paul McCarthy <pauldmccarthy@gmail.com>
Date: Wed, 8 Nov 2017 10:24:03 +0000
Subject: [PATCH] Unit test for face/vertex normal, and fix winding logic in
TriangleMesh class.
---
tests/test_mesh.py | 83 +++++++++++++++++++++++++++++++++++++++++-----
1 file changed, 74 insertions(+), 9 deletions(-)
diff --git a/tests/test_mesh.py b/tests/test_mesh.py
index c2d234fb1..289f48a7e 100644
--- a/tests/test_mesh.py
+++ b/tests/test_mesh.py
@@ -13,7 +13,8 @@ import tempfile
import numpy as np
import pytest
-import fsl.data.mesh as fslmesh
+import fsl.utils.transform as transform
+import fsl.data.mesh as fslmesh
datadir = op.join(op.dirname(__file__), 'testdata')
@@ -26,8 +27,8 @@ def test_create_mesh():
# - create from inmem data
testbase = 'test_mesh.vtk'
testfile = op.join(datadir, testbase)
-
- verts, lens, indices = fslmesh.loadVTKPolydataFile(testfile)
+
+ verts, lens, indices = fslmesh.loadVTKPolydataFile(testfile)
mesh1 = fslmesh.TriangleMesh(testfile)
mesh2 = fslmesh.TriangleMesh(verts, indices)
@@ -36,9 +37,9 @@ def test_create_mesh():
assert mesh2.name == 'TriangleMesh'
assert mesh1.dataSource == testfile
assert mesh2.dataSource is None
-
+
assert mesh1.vertices.shape == (642, 3)
- assert mesh2.vertices.shape == (642, 3)
+ assert mesh2.vertices.shape == (642, 3)
assert mesh1.indices.shape == (1280, 3)
assert mesh2.indices.shape == (1280, 3)
@@ -68,7 +69,7 @@ def test_mesh_loadVertexData():
assert np.all(mesh.getVertexData('inmemdata') == memdata)
mesh.clearVertexData()
-
+
assert mesh.getVertexData(datafile).shape == (642,)
assert np.all(mesh.loadVertexData('inmemdata', memdata) == memdata)
@@ -103,7 +104,7 @@ def test_getFIRSTPrefix():
for fname, expected in passes:
assert fslmesh.getFIRSTPrefix(fname) == expected
-
+
def test_findReferenceImage():
@@ -123,11 +124,75 @@ def test_findReferenceImage():
prefix = fslmesh.getFIRSTPrefix(fname)
imgfname = op.join(testdir, '{}.nii.gz'.format(prefix))
fname = op.join(testdir, fname)
-
+
with open(fname, 'wt') as f: f.write(fname)
with open(imgfname, 'wt') as f: f.write(imgfname)
assert fslmesh.findReferenceImage(fname) == imgfname
-
+
finally:
shutil.rmtree(testdir)
+
+
+def test_normals():
+
+ # vertices of a cube
+ verts = np.array([
+ [-1, -1, -1],
+ [-1, -1, 1],
+ [-1, 1, -1],
+ [-1, 1, 1],
+ [ 1, -1, -1],
+ [ 1, -1, 1],
+ [ 1, 1, -1],
+ [ 1, 1, 1],
+ ])
+
+ # triangles
+ # cw == clockwise, when facing outwards
+ # from the centre of the mesh
+ triangles_cw = np.array([
+ [0, 4, 6], [0, 6, 2],
+ [1, 3, 5], [3, 7, 5],
+ [0, 1, 4], [1, 5, 4],
+ [2, 6, 7], [2, 7, 3],
+ [0, 2, 1], [1, 2, 3],
+ [4, 5, 7], [4, 7, 6],
+ ])
+
+ # ccw == counter-clockwise
+ triangles_ccw = np.array(triangles_cw)
+ triangles_ccw[:, [1, 2]] = triangles_ccw[:, [2, 1]]
+
+ # face normals
+ fnormals = np.array([
+ [ 0, 0, -1], [ 0, 0, -1],
+ [ 0, 0, 1], [ 0, 0, 1],
+ [ 0, -1, 0], [ 0, -1, 0],
+ [ 0, 1, 0], [ 0, 1, 0],
+ [-1, 0, 0], [-1, 0, 0],
+ [ 1, 0, 0], [ 1, 0, 0],
+ ])
+
+ # vertex normals
+ vnormals = np.zeros((8, 3))
+ for i in range(8):
+ faces = np.where(triangles_cw == i)[0]
+ vnormals[i] = fnormals[faces].sum(axis=0)
+ vnormals = transform.normalise(vnormals)
+
+ cw_nofix = fslmesh.TriangleMesh(verts, triangles_cw)
+ cw_fix = fslmesh.TriangleMesh(verts, triangles_cw, fixWinding=True)
+ ccw_nofix = fslmesh.TriangleMesh(verts, triangles_ccw)
+ ccw_fix = fslmesh.TriangleMesh(verts, triangles_ccw, fixWinding=True)
+
+ # ccw triangles should give correct
+ # normals without unwinding
+ assert np.all(np.isclose(cw_nofix .normals, -fnormals))
+ assert np.all(np.isclose(cw_nofix .vnormals, -vnormals))
+ assert np.all(np.isclose(cw_fix .normals, fnormals))
+ assert np.all(np.isclose(cw_fix .vnormals, vnormals))
+ assert np.all(np.isclose(ccw_nofix.normals, fnormals))
+ assert np.all(np.isclose(ccw_nofix.vnormals, vnormals))
+ assert np.all(np.isclose(ccw_fix .normals, fnormals))
+ assert np.all(np.isclose(ccw_fix .vnormals, vnormals))
--
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