generate_regular_polygon()

std::vector< glm::vec3 > MayaFlux::Kinesis::generate_regular_polygon	(	const glm::vec3 &	center,
		float	radius,
		size_t	sides,
		const glm::vec3 &	normal = glm::vec3(0, 0, 1),
		float	phase_offset = 0.0F
	)

Generate vertices of a regular n-gon.

Parameters

center	Polygon centroid
radius	Circumradius (center to vertex distance)
sides	Number of sides (must be >= 3)
normal	Polygon plane normal
phase_offset	Angular offset in radians (default: 0)

Returns

N+1 vertices (closed path)

Vertices positioned at angles: θ_k = (2πk/N) + phase_offset

Definition at line 136 of file GeometryPrimitives.cpp.

{
    if (sides < 3) {
        sides = 3;
    }
 
    std::vector<glm::vec3> vertices;
    vertices.reserve(sides + 1);
 
    glm::vec3 n = glm::normalize(normal);
    glm::vec3 u;
 
    if (std::abs(n.z) < 0.9F) {
        u = glm::normalize(glm::cross(n, glm::vec3(0, 0, 1)));
    } else {
        u = glm::normalize(glm::cross(n, glm::vec3(1, 0, 0)));
    }
 
    glm::vec3 v = glm::cross(n, u);
 
    float angle_step = glm::two_pi<float>() / static_cast<float>(sides);
 
    for (size_t i = 0; i <= sides; ++i) {
        float angle = static_cast<float>(i) * angle_step + phase_offset;
        float cos_a = std::cos(angle);
        float sin_a = std::sin(angle);
 
        glm::vec3 position = center + radius * (cos_a * u + sin_a * v);
 
        vertices.push_back(position);
    }
 
    return vertices;
}

References position, and radius.