Skip to content

Commit 2ebecc1

Browse files
authored
Bug in the face order check (#1394)
* Fixed face order check * Update test_planar_faces.cpp
1 parent dfacc51 commit 2ebecc1

File tree

2 files changed

+33
-13
lines changed

2 files changed

+33
-13
lines changed

src/geometry/planar.md

Lines changed: 7 additions & 13 deletions
Original file line numberDiff line numberDiff line change
@@ -125,20 +125,14 @@ std::vector<std::vector<size_t>> find_faces(std::vector<Point> vertices, std::ve
125125
e = e1;
126126
}
127127
std::reverse(face.begin(), face.end());
128-
int sign = 0;
129-
for (size_t j = 0; j < face.size(); j++) {
130-
size_t j1 = (j + 1) % face.size();
131-
size_t j2 = (j + 2) % face.size();
132-
int64_t val = vertices[face[j]].cross(vertices[face[j1]], vertices[face[j2]]);
133-
if (val > 0) {
134-
sign = 1;
135-
break;
136-
} else if (val < 0) {
137-
sign = -1;
138-
break;
139-
}
128+
Point p1 = vertices[face[0]];
129+
__int128 sum = 0;
130+
for (int j = 0; j < face.size(); ++j) {
131+
Point p2 = vertices[face[j]];
132+
Point p3 = vertices[face[(j + 1) % face.size()]];
133+
sum += (p2 - p1).cross(p3 - p2);
140134
}
141-
if (sign <= 0) {
135+
if (sum <= 0) {
142136
faces.insert(faces.begin(), face);
143137
} else {
144138
faces.emplace_back(face);

test/test_planar_faces.cpp

Lines changed: 26 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -93,8 +93,34 @@ void test_cycle_with_chain() {
9393
assert(equal_cycles(faces[1], {2, 5, 4, 5, 2, 1, 0, 3}));
9494
}
9595

96+
void test_ccw_angle() {
97+
std::vector<Point> p = {
98+
Point(0, 2),
99+
Point(1, 3),
100+
Point(0, 1),
101+
Point(1, 0),
102+
Point(-1, 0),
103+
Point(-1, 3)
104+
};
105+
106+
std::vector<std::vector<size_t>> adj = {
107+
{1, 5},
108+
{0, 2},
109+
{1, 3},
110+
{2, 4},
111+
{3, 5},
112+
{0, 4}
113+
};
114+
115+
auto faces = find_faces(p, adj);
116+
assert(faces.size() == 2u);
117+
assert(equal_cycles(faces[0], {0, 1, 2, 3, 4, 5}));
118+
assert(equal_cycles(faces[1], {5, 4, 3, 2, 1, 0}));
119+
}
120+
96121
int main() {
97122
test_simple();
98123
test_degenerate();
99124
test_cycle_with_chain();
125+
test_ccw_angle();
100126
}

0 commit comments

Comments
 (0)
pFad - Phonifier reborn

Pfad - The Proxy pFad of © 2024 Garber Painting. All rights reserved.

Note: This service is not intended for secure transactions such as banking, social media, email, or purchasing. Use at your own risk. We assume no liability whatsoever for broken pages.


Alternative Proxies:

Alternative Proxy

pFad Proxy

pFad v3 Proxy

pFad v4 Proxy