Merge pull request #21 from andrsd/insc-poly

Adding `InscribedPolygon`

Author: andrsd

include/formo/inscribed_polygon.h

@@ -0,0 +1,39 @@
+// SPDX-FileCopyrightText: 2024 David Andrs <andrsd@gmail.com>
+// SPDX-License-Identifier: MIT
+
+#pragma once
+
+#include "formo/wire.h"
+#include <vector>
+
+namespace formo {
+
+class Axis2;
+class Point;
+class Vector;
+
+class InscribedPolygon : public Wire {
+public:
+    /// Create circumscribed polygon from radius and number of sides
+    ///
+    /// @param radius Radius if the circle
+    /// @param sides Number of sides (must be 3 or more)
+    InscribedPolygon(const Axis2 & ax2, double radius, int sides);
+
+    /// Create circumscribed polygon from a point and number of sides
+    ///
+    /// @param pt1 Point defining the circle and the first point of the polygon
+    /// @param sides Number of sides (must be 3 or more)
+    InscribedPolygon(const Axis2 & ax2, const Point & pt1, int sides);
+
+private:
+    std::vector<Point> build_points(const Axis2 & ax2, const Vector & vec);
+    TopoDS_Wire build_polygon(const std::vector<Point> & points);
+
+    /// Radius of the circle
+    double radius;
+    /// Number of sides
+    int n_sides;
+};
+
+} // namespace formo

python/src/formo.cpp

@@ -23,6 +23,7 @@
 #include "formo/geometry.h"
 #include "formo/iges_file.h"
 #include "formo/io.h"
+#include "formo/inscribed_polygon.h"
 #include "formo/line.h"
 #include "formo/linear_pattern.h"
 #include "formo/operations.h"
@@ -274,6 +275,13 @@ PYBIND11_MODULE(formo, m)
             py::arg("ax2"), py::arg("pt1"), py::arg("sides"))
     ;
 
+    py::class_<InscribedPolygon, Wire>(m, "InscribedPolygon")
+        .def(py::init<const Axis2 &, double, int>(),
+            py::arg("ax2"), py::arg("radius"), py::arg("sides"))
+        .def(py::init<const Axis2 &, const Point &, int>(),
+            py::arg("ax2"), py::arg("pt1"), py::arg("sides"))
+    ;
+
     //
 
     py::class_<ArcOfCircle, Edge>(m, "ArcOfCircle")

src/inscribed_polygon.cpp

@@ -0,0 +1,72 @@
+// SPDX-FileCopyrightText: 2024 David Andrs <andrsd@gmail.com>
+// SPDX-License-Identifier: MIT
+
+#include "formo/inscribed_polygon.h"
+#include "formo/axis1.h"
+#include "formo/axis2.h"
+#include "formo/point.h"
+#include "formo/vector.h"
+#include "formo/exception.h"
+#include "BRepBuilderAPI_MakePolygon.hxx"
+
+namespace formo {
+
+InscribedPolygon::InscribedPolygon(const Axis2 & ax2, double radius, int sides) :
+    Wire(),
+    radius(radius),
+    n_sides(sides)
+{
+    if (sides < 3)
+        throw Exception("InscribedPolygon needs at least 3 sides");
+
+    auto r_out = radius / (0.5 * std::sqrt(3));
+    auto points = build_points(ax2, r_out * ax2.x_direction());
+    auto polygon = build_polygon(points);
+    set_wire(polygon);
+}
+
+InscribedPolygon::InscribedPolygon(const Axis2 & ax2, const Point & pt1, int sides) :
+    Wire(),
+    radius(0.),
+    n_sides(sides)
+{
+    if (sides < 3)
+        throw Exception("InscribedPolygon needs at least 3 sides");
+
+    auto vec = Vector(ax2.location(), pt1);
+    this->radius = vec.magnitude();
+    auto r_out = this->radius / (0.5 * std::sqrt(3));
+    auto points = build_points(ax2, r_out * vec);
+    auto polygon = build_polygon(points);
+    set_wire(polygon);
+}
+
+std::vector<Point>
+InscribedPolygon::build_points(const Axis2 & ax2, const Vector & start_vec)
+{
+    std::vector<Point> points;
+    auto ctr_pt = ax2.location();
+    Axis1 ctr_ax1(ctr_pt, ax2.direction());
+    auto dangle = 2 * M_PI / n_sides;
+    for (int i = 0; i < n_sides; i++) {
+        auto vec = start_vec.rotated(ctr_ax1, i * dangle);
+        auto pt1 = ctr_pt + vec;
+        points.emplace_back(pt1);
+    }
+    return points;
+}
+
+TopoDS_Wire
+InscribedPolygon::build_polygon(const std::vector<Point> & points)
+{
+    BRepBuilderAPI_MakePolygon polygon;
+    for (auto & pt : points)
+        polygon.Add(pt);
+    polygon.Close();
+    polygon.Build();
+    if (!polygon.IsDone())
+        throw Exception("Polygon was not created");
+    return polygon.Wire();
+}
+
+} // namespace formo

test/src/InscribedPolygon_test.cpp

@@ -0,0 +1,23 @@
+#include "gmock/gmock.h"
+#include "formo/inscribed_polygon.h"
+#include "formo/axis2.h"
+#include "formo/direction.h"
+#include "formo/exception.h"
+
+using namespace formo;
+
+TEST(InscribedPolygonTest, ctor1)
+{
+    Axis2 ax2(Point(1, 1, 0), Direction(0, 0, 1));
+    InscribedPolygon plgn(ax2, 2, 3);
+
+    EXPECT_THROW({ InscribedPolygon(ax2, 2, 1); }, Exception);
+}
+
+TEST(InscribedPolygonTest, ctor2)
+{
+    Axis2 ax2(Point(1, 1, 0), Direction(0, 0, 1));
+    InscribedPolygon plgn(ax2, Point(0, 1, 0), 3);
+
+    EXPECT_THROW({ InscribedPolygon(ax2, Point(0, 1, 0), 1); }, Exception);
+}