По одним и тем же точкам получаются разные границы фигур при использовании разных примитивов: ConvexShape и LinesStrip

#include <SFML/Graphics.hpp>
#include <iostream>
using namespace sf;
 
int main() {
 
    int wWidth = 800, wHeight = wWidth;
 
    RenderWindow window(VideoMode(wWidth, wHeight), "Lab2");
 
    /*std::vector<float> posX = {
        270, 270, 400, 500, 380, 420, 360, 360
    };
 
    std::vector<float> posY = {
        300, 200, 160, 230, 370, 260, 280, 210
    };*/
 
    std::vector<float> posX = {
        360, 360, 420, 380, 500, 400, 270, 270
    };
 
    std::vector<float> posY = {
        210, 280, 260, 370, 230, 160, 200, 300
    };
 
    ConvexShape convex;
    convex.setPointCount(posX.size());
 
    for (int i = 0; i < posX.size(); ++i) {
        convex.setPoint(i, Vector2f(posX[i], posY[i]));
        convex.setFillColor(Color(10, 20, 30, 150));
    }
 
    VertexArray verices(LinesStrip, posX.size()+1);
    for (int i = 0; i < posX.size(); ++i) {
        verices[i].position = Vector2f(posX[i], posY[i]);
        verices[i].color = Color::Green;
    }
    verices[posX.size()].position = Vector2f(posX[0], posY[0]);
    verices[posX.size()].color = Color::Green;
 
    while (window.isOpen()) {
        Event event;
        while (window.pollEvent(event)) {
            if (event.type == Event::Closed)
                window.close();
        }
 
        window.clear(Color(160, 160, 160));
 
        window.draw(convex);
        window.draw(verices);
        window.display();
    }
 
    return 0;
}

#include <SFML/Graphics.hpp>
#include <iostream>
using namespace sf;
 
#include <cassert>
#include <algorithm>
class My_convex : public sf::Drawable, public sf::Transformable
{
public:
    using data = std::vector<float>;
 
    My_convex(const data& x, const data& y) : m_points(sf::TriangleFan, x.size() + 2)
    {
        assert(x.size() && x.size() == y.size());
        const auto mm_x = std::minmax_element(x.begin(), x.end());
        const auto mm_y = std::minmax_element(y.begin(), y.end());
        const float center_x = (*mm_x.first + *mm_x.second) / 2;
        const float center_y = (*mm_y.first + *mm_y.second) / 2;
        m_points[0] = sf::Vertex(sf::Vector2f(center_x, center_y));
        for (size_t i = 1; i < x.size() + 1; ++i)
        {
            m_points[i] = sf::Vertex(sf::Vector2f(x[i - 1], y[i - 1]));
        }
        m_points[x.size() + 1] = m_points[1];
    }
 
    void set_color(sf::Color cl)
    {
        const size_t count = m_points.getVertexCount();
        for (size_t i = 0; i < count; ++i)
            m_points[i].color = cl;
    }
 
private:
 
    void draw(sf::RenderTarget& target, sf::RenderStates states) const override
    {
        states.transform *= getTransform();
        target.draw(m_points, states);
    }
 
    sf::VertexArray m_points;
};
 
int main() {
 
    int wWidth = 800, wHeight = wWidth;
 
    RenderWindow window(VideoMode(wWidth, wHeight), "Lab2");
 
    /*std::vector<float> posX = {
        270, 270, 400, 500, 380, 420, 360, 360
    };
 
    std::vector<float> posY = {
        300, 200, 160, 230, 370, 260, 280, 210
    };*/
 
    std::vector<float> posX = {
        360, 360, 420, 380, 500, 400, 270, 270
    };
 
    std::vector<float> posY = {
        210, 280, 260, 370, 230, 160, 200, 300
    };
 
    ConvexShape convex;
    convex.setPointCount(posX.size());
 
    const auto cl = Color(10, 20, 30, 150);
 
    for (int i = 0; i < posX.size(); ++i) {
        convex.setPoint(i, Vector2f(posX[i], posY[i]));
    }
    convex.setFillColor(cl);
 
    VertexArray verices(LineStrip, posX.size() + 1);
    for (int i = 0; i < posX.size(); ++i) {
        verices[i].position = Vector2f(posX[i], posY[i]);
        verices[i].color = Color::Green;
    }
    verices[posX.size()].position = Vector2f(posX[0], posY[0]);
    verices[posX.size()].color = Color::Green;
 
    My_convex shape(posX, posY);
    shape.set_color(cl);
    shape.move(0.0f, 300.0f);
 
    while (window.isOpen()) {
        Event event;
        while (window.pollEvent(event)) {
            if (event.type == Event::Closed)
                window.close();
        }
 
        window.clear(Color(160, 160, 160));
 
        window.draw(convex);
        window.draw(shape);
        //window.draw(verices);
        window.display();
    }
 
    return 0;
}