绘制超过 500 个形状时 SFML 变慢

Question

我是 SFML 的新手，我想实现流体类群模拟。但是，我发现当同时绘制超过500个形状时，fps下降得很快。

我如何改进下面的代码以使其更快地达到运行？

#include <SFML/Graphics.hpp>
#include <vector>
#include <iostream>
sf::ConvexShape newShape() {
    sf::ConvexShape shape(3);
    shape.setPoint(0, sf::Vector2f(0, 0));
    shape.setPoint(1, sf::Vector2f(-7, 20));
    shape.setPoint(2, sf::Vector2f(7, 20));
    shape.setOrigin(0, 10);
    shape.setFillColor(sf::Color(49, 102, 156, 150));
    shape.setOutlineColor(sf::Color(125, 164, 202, 150));
    shape.setOutlineThickness(1);
    shape.setPosition(rand() % 800, rand() % 600);
    shape.setRotation(rand() % 360);
    return shape;
}

int main() { 
    sf::Clock dtClock, fpsTimer;
    sf::RenderWindow window(sf::VideoMode(800, 600), "Too Slow");
    std::vector<sf::ConvexShape> shapes;
    for (int i = 0; i < 1000; i++) shapes.push_back(newShape());
    while (window.isOpen()) {
        window.clear(sf::Color(50, 50, 50));
        for (auto &shape : shapes) { shape.rotate(0.5); window.draw(shape); }
        window.display();
        float dt = dtClock.restart().asSeconds();
        if (fpsTimer.getElapsedTime().asSeconds() > 1) {
            fpsTimer.restart();
            std::cout << ((1.0 / dt > 60) ? 60 : (1.0 / dt)) << std::endl;
        }
    }
}

我有以下表现：

Shapes   FPS
10       60
100      60
500      60
600      60
700      55
800      50
900      45
1000     21

我的目标是在屏幕上显示大约 5k 个 boid。

编辑

我正在 Windows 11 上构建项目，在 WSL2 下启用了 vGPU。当使用 Visual Studio 在 Windows 11 上进行本地测试时，我获得了更好的性能（我可以运行 5k boids 以 60 FPS）

Answer 1

问题是很多绘图调用。这是该程序的缓慢部分。为了解决这个问题，我们可以将所有三角形放入单个顶点数组中，并仅在该数组上调用绘图。这样我们将加快程序。问题是您必须实现自己的旋转方法。我实现了下面的方法并进行了编辑，因此函数 returns 单顶点数组中的三角形。

#include <SFML/Graphics.hpp>
#include <iostream>
//This function returns vertex array by given number of triangles
sf::VertexArray newShape(int numberOfTriangles) {
    sf::VertexArray shape(sf::Triangles);
    //we are going trough every point in each triangle
    for (int i=0;i<3*numberOfTriangles;i++){
        //creating points of triangles as vertexes 1, 2 and 3
        sf::Vertex v1(sf::Vector2f(rand() % 800, rand() % 600));
        sf::Vertex v2(sf::Vector2f(v1.position.x - 7, v1.position.y - 20));
        sf::Vertex v3(sf::Vector2f(v1.position.x + 7, v1.position.y - 20));
        //setting color
        v1.color = v2.color = v3.color = sf::Color(49, 102, 156, 150);
        //rotating for random angle
        sf::Transform transform;
        transform.rotate(rand()%90, (v2.position.x + v3.position.x) / 2,v1.position.y - 10);
        v1.position = transform.transformPoint(v1.position);
        v2.position = transform.transformPoint(v2.position);
        v3.position = transform.transformPoint(v3.position);
        //appending them into vertex array
        shape.append(v1);
        shape.append(v2);
        shape.append(v3);

    }
    return shape;   
}
//rotate function finds the middle of 3 vertexes and rotates them
void rotate(sf::VertexArray& array, double angle){
    for (int i=0;i<array.getVertexCount();i+=3){
        sf::Transform transform;
        transform.rotate(angle, (array[i+1].position.x + array[i+2].position.x) / 2, (array[i].position.y + array[i+1].position.y)/2);
        array[i].position = transform.transformPoint(array[i].position);
        array[i+1].position = transform.transformPoint(array[i+1].position);
        array[i+2].position = transform.transformPoint(array[i+2].position);
    }

}
int main() { 
    sf::Clock dtClock, fpsTimer;
    sf::RenderWindow window(sf::VideoMode(800, 600), "Too Slow");
    //creating new array with 30000 triangles
    sf::VertexArray shapes = newShape(30000);
    window.setFramerateLimit(60);
    while (window.isOpen()) {
        //event to close window on close button
        sf::Event event;
        while (window.pollEvent(event))
        {
            if (event.type == sf::Event::Closed)
                window.close();
        }

        window.clear(sf::Color(50, 50, 50));
        //no need for for now, as you can rotate them all in function and draw them together
        rotate(shapes,5); 
        window.draw(shapes); 
        window.display();
        float dt = dtClock.restart().asSeconds();
        if (fpsTimer.getElapsedTime().asSeconds() > 1) {
            fpsTimer.restart();
            std::cout << ((1.0 / dt > 60) ? 60 : (1.0 / dt)) << std::endl;
        }
    }
}

现在的瓶颈不是绘图而是旋转，我用 100000 个三角形测试了这段代码，我得到了大约 45 fps。对于 1000000，由于旋转，我的帧率变得很差。

绘制超过 500 个形状时 SFML 变慢

SFML slow when drawing more than 500 shapes

c++

performance

sfml