我是 SFML 的新手，我想實作流體物體模擬。但是，我意識到當同時繪制超過 500 個形狀時，fps 會迅速下降。
如何改進下面的代碼以使其運行速度更快？
#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;
}
}
}
我有以下表現：
Shapes FPS
10 60
100 60
500 60
600 60
700 55
800 50
900 45
1000 21
我的目標是在螢屏上顯示大約 5k 個 boid。
編輯
我在啟用了 vGPU 的 WSL2 下在 Windows 11 上構建專案。在使用 Visual Studio 在 Windows 11 上進行本機測驗時，我獲得了更好的性能（我可以以 60 FPS 的速度運行 5k boid）
uj5u.com熱心網友回復：
問題是很多繪制呼叫。這是這個程式的緩慢部分。為了解決這個問題，我們可以將所有三角形放入單個頂點陣列中，并僅對該陣列呼叫 draw。這樣我們就可以加快程式的速度。問題在于您必須實作自己的旋轉方法。我實作了下面的方法并進行了編輯，以便該函式回傳單個頂點陣列中的三角形。
#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;
}
}
}
現在的瓶頸不是繪圖而是旋轉，我用 100000 個三角形測驗了這段代碼，我得到了大約 45 fps。使用 1000000 時，由于旋轉，我的幀率變差了。
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