How to: Generate points on a circle from a CircleKit (HPS)

[simon]

Below is sample code on how to generate points on a circle from CircleKit (center_pos, radius, vector_normal).

#include <iostream>
#include <vector>
#include <cmath>


#ifndef M_PI
#define M_PI 3.14159265358979323846
#endif

struct Vector3 {
    double x, y, z;

    Vector3() : x(0), y(0), z(0) {}
    Vector3(double x, double y, double z) : x(x), y(y), z(z) {}

    Vector3 operator+(const Vector3& v) const {
        return Vector3(x + v.x, y + v.y, z + v.z);
    }

    Vector3 operator*(double scalar) const {
        return Vector3(x * scalar, y * scalar, z * scalar);
    }

    Vector3 cross(const Vector3& v) const {
        return Vector3(
            y * v.z - z * v.y,
            z * v.x - x * v.z,
            x * v.y - y * v.x
        );
    }

    Vector3 normalize() const {
        double length = std::sqrt(x * x + y * y + z * z);
        return Vector3(x / length, y / length, z / length);
    }
};

std::vector<Vector3> computeCirclePoints3D(const Vector3& center, double radius, const Vector3& normal, int numPoints) {
    std::vector<Vector3> points;
    points.reserve(numPoints);

    // Generate a basis for the plane
    Vector3 arbitraryVec(1, 0, 0); // Choose an arbitrary vector
    if (std::abs(normal.x) < 1e-6 && std::abs(normal.y) < 1e-6) {
        arbitraryVec = Vector3(0, 1, 0); // Handle edge case when normal is along Z-axis
    }

    Vector3 U = normal.cross(arbitraryVec).normalize();
    Vector3 V = normal.cross(U).normalize();

    // Angle between each point
    double angleIncrement = 2.0 * M_PI / numPoints;

    for (int i = 0; i < numPoints; ++i) {
        double angle = i * angleIncrement;
        Vector3 point = center + (U * (radius * cos(angle))) + (V * (radius * sin(angle)));
        points.push_back(point);
    }

    return points;
}

void CHPSView::OnUserCode4()
{
    Vector3 center(0, 0, 0);
    double radius = 10.0;
    Vector3 normal(0, 0, 1);

  // amount of points to generate
    int numPoints = 8;

    HPS::SegmentKey modelKey = GetCanvas().GetFrontView().GetAttachedModel().GetSegmentKey();
    modelKey.Subsegment("circle").InsertCircle(HPS::Point(0, 0, 0), (float)radius, HPS::Vector(0, 0, 1));

    std::vector<Vector3> points = computeCirclePoints3D(center, radius, normal, numPoints);

	modelKey.Subsegment("markers").GetVisibilityControl().SetMarkers(true);
	modelKey.Subsegment("markers").GetMaterialMappingControl().SetMarkerColor(HPS::RGBAColor(1, 0, 0));

	


    for (const auto& point : points) {
		modelKey.Subsegment("markers").InsertMarker(HPS::Point(point.x, point.y, point.z));
    }

	GetCanvas().GetFrontView().FitWorld().UpdateWithNotifier().Wait();
    //return 0;

}
//! [user_code]