如何在 C++ 中使用 SFML 绘制高级形状？

Question

What is the best way to draw advanced custom shapes with a lot of roundings while using the SFML library in C++?

I know how to draw shapes like rectangles or circles with the SFML library in C++. But if you want to make a custom shape you can make use of a vertex array.

If I want to draw a shape like this for example:

You can start with a point on the top-left to the top-right. But then you have to deal with a lot of bumps. What is the best way to draw this shape?

A function can be created to calculate all the points in the curve, But is it correct to use 1000 points for small shape like this? (especially if you have a lot of these shapes)

Answer 1

Here's something that I made for you. This might sound silly, but what it does is, you can draw your shapes outline, then click the right mouse button to convert the rectangles positions (X,Y) into points which a convex shape will take and create itself into a nice shape.

//This is not necessary, but it helps if you going to move the camera.
    Vector2i pixelPos = Mouse::getPosition(*Twin);
    Vector2f worldPos = Twin->mapPixelToCoords(pixelPos);

    // declare the variables
    RectangleShape* brush;
    vector<RectangleShape> brushV;
    ConvexShape yourShape;
    vector<Vector2f> pos;
    brush = new RectangleShape;

    // the brush, which creates rectangles
    if (Mouse::isButtonPressed(Mouse::Left))
    {
        brushV.push_back(*brush);
        brushV[brushV.size() - 1].setSize(Vector2f(10, 10));
        brushV[brushV.size() - 1].setPosition(Vector2f(worldPos));
        pos.push_back(worldPos);
    }

    // creates the whole shape which you drew
    if (Mouse::isButtonPressed(Mouse::Right))
    {
        yourShape.setPointCount(pos.size());
        for (int i = 0; i < pos.size(); i++)
        {
            yourShape.setPoint(i, pos[i]);
        }
        brushV.clear();
    }

    // render
    for (int i = 0; i < brushV.size(); i++)
    {
        window->draw(brushV[i]);
    }
    window->draw(yourShape);

If the edges look rough you can try using antialiased.

sf::ContextSettings settings;
settings.antialiasingLevel = 8;