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delfrrr#2 parity with js: mapbox/delaunator@b1f360c
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@delfrrr
delfrrr committed Sep 20, 2018
1 parent d5cc9f4 commit 4f072c2
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Showing 3 changed files with 70 additions and 18 deletions.
26 changes: 20 additions & 6 deletions examples/utils.hpp
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Original file line number Diff line number Diff line change
Expand Up @@ -8,7 +8,7 @@

namespace utils {

std::string read_file(const char* filename) {
inline std::string read_file(const char* filename) {
std::ifstream input_file(filename);
if(input_file.good()) {
std::string json_str(
Expand All @@ -22,7 +22,7 @@ std::string read_file(const char* filename) {
}
}

std::vector<double> get_geo_json_points(std::string const& json) {
inline std::vector<double> get_geo_json_points(std::string const& json) {
rapidjson::Document document;
if(document.Parse(json.c_str()).HasParseError()) {
throw std::runtime_error("Cannot parse JSON");
Expand All @@ -40,8 +40,22 @@ std::vector<double> get_geo_json_points(std::string const& json) {
return coords;
}

std::vector<double> get_array_points(std::string const& json) {
std::vector<double> points;
template <typename T>
inline T get_json_value(const rapidjson::Value &v);

template <>
inline double get_json_value(const rapidjson::Value &v) {
return v.GetDouble();
}

template <>
inline size_t get_json_value(const rapidjson::Value &v) {
return static_cast<size_t>(v.GetUint64());
}

template <typename T>
inline std::vector<T> get_array_points(std::string const& json) {
std::vector<T> points;
rapidjson::Document document;
if(document.Parse(json.c_str()).HasParseError()) {
throw std::runtime_error("Cannot parse JSON");
Expand All @@ -51,10 +65,10 @@ std::vector<double> get_array_points(std::string const& json) {
}
points.reserve(static_cast<std::size_t>(document.Size()));
for(rapidjson::SizeType i = 0; i < document.Size(); i++) {
points.push_back(document[i].GetDouble());
// points.push_back(document[i].GetDouble());
points.push_back(get_json_value<T>(document[i]));
}
return points;

}

} // end ns utils
36 changes: 26 additions & 10 deletions include/delaunator.hpp
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Original file line number Diff line number Diff line change
Expand Up @@ -168,6 +168,8 @@ class Delaunator {

Delaunator(std::vector<double> const& in_coords);

double get_hull_area();

private:
std::vector<std::size_t> m_hash;
std::vector<DelaunatorPoint> m_hull;
Expand Down Expand Up @@ -401,6 +403,16 @@ Delaunator::Delaunator(std::vector<double> const& in_coords)
}
}

double Delaunator::get_hull_area() {
double hull_area = 0;
size_t e = m_hull_entry;
do {
hull_area += (m_hull[e].x - m_hull[m_hull[e].prev].x) * (m_hull[e].y + m_hull[m_hull[e].prev].y);
e = m_hull[e].next;
} while (e != m_hull_entry);
return hull_area;
}

std::size_t Delaunator::remove_node(std::size_t node) {
m_hull[m_hull[node].prev].next = m_hull[node].next;
m_hull[m_hull[node].next].prev = m_hull[node].prev;
Expand All @@ -409,7 +421,7 @@ std::size_t Delaunator::remove_node(std::size_t node) {
}

std::size_t Delaunator::legalize(std::size_t a) {
std::size_t b = halfedges[a];
const std::size_t b = halfedges[a];

/* if the pair of triangles doesn't satisfy the Delaunay condition
* (p1 is inside the circumcircle of [p0, pl, pr]), flip them,
Expand All @@ -426,17 +438,21 @@ std::size_t Delaunator::legalize(std::size_t a) {
* \||/ \ /
* pr pr
*/
std::size_t a0 = a - a % 3;
std::size_t b0 = b - b % 3;
const std::size_t a0 = a - a % 3;
const std::size_t b0 = b - b % 3;

const std::size_t al = a0 + (a + 1) % 3;
const std::size_t ar = a0 + (a + 2) % 3;
const std::size_t bl = b0 + (b + 2) % 3;

std::size_t al = a0 + (a + 1) % 3;
std::size_t ar = a0 + (a + 2) % 3;
std::size_t bl = b0 + (b + 2) % 3;
const std::size_t p0 = triangles[ar];
const std::size_t pr = triangles[a];
const std::size_t pl = triangles[al];
const std::size_t p1 = triangles[bl];

std::size_t p0 = triangles[ar];
std::size_t pr = triangles[a];
std::size_t pl = triangles[al];
std::size_t p1 = triangles[bl];
// if (b == INVALID_INDEX) {
// return ar;
// }

const bool illegal = in_circle(
coords[2 * p0],
Expand Down
26 changes: 24 additions & 2 deletions test/delaunator.test.cpp
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Original file line number Diff line number Diff line change
@@ -1,5 +1,6 @@
#include "../examples/utils.hpp"
#include <catch.hpp>
#include <cmath>
#include <delaunator.hpp>

namespace {
Expand All @@ -13,14 +14,30 @@ void validate(const std::vector<double>& coords) {
(i2 != delaunator::INVALID_INDEX) && (d.halfedges[i2] != i)));
}
}

SECTION("validate triangulation") {
double hull_area = d.get_hull_area();
double triangles_area = 0.0;

for (size_t i = 0; i < d.triangles.size(); i += 3) {
const double ax = coords[2 * d.triangles[i]];
const double ay = coords[2 * d.triangles[i] + 1];
const double bx = coords[2 * d.triangles[i + 1]];
const double by = coords[2 * d.triangles[i + 1] + 1];
const double cx = coords[2 * d.triangles[i + 2]];
const double cy = coords[2 * d.triangles[i + 2] + 1];
triangles_area += std::fabs((by - ay) * (cx - bx) - (bx - ax) * (cy - by));
}
REQUIRE(triangles_area == Approx(hull_area));
}
}
} // namespace

TEST_CASE("triangles match JS version ouput", "[Delaunator]") {
std::string points_str = utils::read_file("./test/test-files/playgrounds-1356-epsg-3857.geojson");
std::string triangles_str = utils::read_file("./test/test-files/playgrounds-1356-triangles.json");
std::vector<double> coords = utils::get_geo_json_points(points_str);
std::vector<double> triangles = utils::get_array_points(triangles_str);
std::vector<size_t> triangles = utils::get_array_points<size_t>(triangles_str);
delaunator::Delaunator delaunator(coords);

SECTION("length of triangles is the same") {
Expand All @@ -29,7 +46,7 @@ TEST_CASE("triangles match JS version ouput", "[Delaunator]") {

SECTION("values are the same") {
for (std::size_t i = 0; i < triangles.size(); i++) {
REQUIRE(delaunator.triangles[i] == Approx(triangles[i]));
REQUIRE(delaunator.triangles[i] == triangles[i]);
}
}
}
Expand All @@ -48,3 +65,8 @@ TEST_CASE("mapbox/delaunator/issues/24", "[Delaunator]") {
std::vector<double> coords = { 382, 302, 382, 328, 382, 205, 623, 175, 382, 188, 382, 284, 623, 87, 623, 341, 141, 227 };
validate(coords);
}

TEST_CASE("mapbox/delaunator/issues/13", "[Delaunator]") {
std::vector<double> coords = { 4, 1, 3.7974166882130675, 2.0837249985614585, 3.2170267516619773, 3.0210869309396715, 2.337215067329615, 3.685489874065187, 1.276805078389906, 3.9872025288851036, 0.17901102978375127, 3.885476929518457, -0.8079039091377689, 3.3940516818407187, -1.550651407188842, 2.5792964886320684, -1.9489192990517052, 1.5512485534497125, -1.9489192990517057, 0.44875144655029087, -1.5506514071888438, -0.5792964886320653, -0.8079039091377715, -1.394051681840717, 0.17901102978374794, -1.8854769295184561, 1.276805078389902, -1.987202528885104, 2.337215067329611, -1.6854898740651891, 3.217026751661974, -1.021086930939675, 3.7974166882130653, -0.08372499856146409 };
validate(coords);
}

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