进行一些C ++编码并使用SFML库。我按照教程使用Xcode从模板运行示例代码，并进行了一些修改。代码如下
//
// Disclamer:
// ----------
//
// This code will work only if you selected window, graphics and audio.
//
// Note that the "Run Script" build phase will copy the required frameworks
// or dylibs to your application bundle so you can execute it on any OS X
// computer.
//
// Your resource files (images, sounds, fonts, ...) are also copied to your
// application bundle. To get the path to these resource, use the helper
// method resourcePath() from ResourcePath.hpp
//
#include <SFML/Graphics.hpp>
#include <cmath>
class Pixels : public sf::Drawable, public sf::Transformable
{
public:
Pixels(int nrOfPixels):
nPixels(nrOfPixels),
nVertices(sf::Points,nrOfPixels)
{
initializePixels();
}
void initializePixels()
{
for (int i=0;i<nPixels.size();i++)
{
Pixel& p = nPixels[i];
p.angle = (std::rand() % 360) * 3.14f / 180.f;
p.speed = (std::rand() % 50) + 50.f;
p.position = sf::Vector2f(1+rand() % 500,1+rand()%500);
p.color = sf::Color(rand()%256,rand()%256,rand()%256);
p.velocity = sf::Vector2f(std::cos(p.angle)*p.speed,std::sin(p.angle)*p.speed);
nVertices[i].position = p.position;
nVertices[i].color = p.color;
}
}
void updatePixels(sf::Time elapsed)
{
for (int i=0;i<nPixels.size();i++)
{
Pixel& p = nPixels[i];
nVertices[i].position += p.velocity * elapsed.asSeconds();
if (nVertices[i].position.x < 1)
{
nVertices[i].position.x = 1;
p.velocity.x = - p.velocity.x;
} else if ( nVertices[i].position.x > 500)
{
nVertices[i].position.x = 500;
p.velocity.x = -p.velocity.x;
}
if (nVertices[i].position.y < 1)
{
nVertices[i].position.y = 1;
p.velocity.y = - p.velocity.y;
} else if ( nVertices[i].position.y > 500)
{
nVertices[i].position.y = 500;
p.velocity.y = -p.velocity.y;
}
}
}
private:
virtual void draw(sf::RenderTarget& target, sf::RenderStates states) const
{
// apply the transform
states.transform *= getTransform();
// our particles don't use a texture
states.texture = NULL;
// draw the vertex array
target.draw(nVertices, states);
}
private:
struct Pixel
{
sf::Vector2f velocity;
sf::Vector2f position;
sf::Color color;
float angle;
float speed;
};
std::vector<Pixel> nPixels;
sf::VertexArray nVertices;
};
int main(int, char const**)
{
// Create the main window
sf::RenderWindow window(sf::VideoMode(500, 500), "Random Particles");
Pixels pixels(10000);
// create a clock to track the elapsed time
sf::Clock clock;
// Start the game loop
while (window.isOpen())
{
// Process events
sf::Event event;
while (window.pollEvent(event))
{
// Close window: exit
if (event.type == sf::Event::Closed) {
window.close();
}
// Escape pressed: exit
if (event.type == sf::Event::KeyPressed && event.key.code == sf::Keyboard::Escape) {
window.close();
}
}
// Clear screen
window.clear();
sf::Time elapsed = clock.restart();
pixels.updatePixels(elapsed);
// draw it
window.draw(pixels);
// Update the window
window.display();
}
return EXIT_SUCCESS;
}
Xcode可以编译，链接和运行代码。但是我想知道如何从终端编译它。
首先我尝试了
g++ main.cpp
但导致找不到#include <SFML/Graphics.hpp>。所以我进入了
g++ main.cpp -I /usr/local/include
链接标题。但是这会产生以下错误：
Undefined symbols for architecture x86_64:
"sf::VertexArray::VertexArray(sf::PrimitiveType, unsigned long)", referenced from:
Pixels::Pixels(int) in main-de105c.o
"sf::VertexArray::operator[](unsigned long)", referenced from:
Pixels::updatePixels(sf::Time) in main-de105c.o
Pixels::initializePixels() in main-de105c.o
"sf::RenderStates::Default", referenced from:
_main in main-de105c.o
"sf::RenderTarget::draw(sf::Drawable const&, sf::RenderStates const&)", referenced from:
_main in main-de105c.o
Pixels::draw(sf::RenderTarget&, sf::RenderStates) const in main-de105c.o
"sf::RenderTarget::clear(sf::Color const&)", referenced from:
_main in main-de105c.o
"sf::RenderWindow::RenderWindow(sf::VideoMode, sf::String const&, unsigned int, sf::ContextSettings const&)", referenced from:
_main in main-de105c.o
"sf::RenderWindow::~RenderWindow()", referenced from:
_main in main-de105c.o
"sf::Transformable::Transformable()", referenced from:
Pixels::Pixels(int) in main-de105c.o
"sf::Transformable::~Transformable()", referenced from:
Pixels::~Pixels() in main-de105c.o
Pixels::Pixels(int) in main-de105c.o
"sf::Clock::restart()", referenced from:
_main in main-de105c.o
"sf::Clock::Clock()", referenced from:
_main in main-de105c.o
"sf::Color::Color(unsigned char, unsigned char, unsigned char, unsigned char)", referenced from:
_main in main-de105c.o
Pixels::initializePixels() in main-de105c.o
"sf::Color::Color()", referenced from:
Pixels::Pixel::Pixel() in main-de105c.o
"sf::String::String(char const*, std::__1::locale const&)", referenced from:
_main in main-de105c.o
"sf::Window::close()", referenced from:
_main in main-de105c.o
"sf::Window::display()", referenced from:
_main in main-de105c.o
"sf::Window::pollEvent(sf::Event&)", referenced from:
_main in main-de105c.o
"sf::VideoMode::VideoMode(unsigned int, unsigned int, unsigned int)", referenced from:
_main in main-de105c.o
"sf::operator*=(sf::Transform&, sf::Transform const&)", referenced from:
Pixels::draw(sf::RenderTarget&, sf::RenderStates) const in main-de105c.o
"sf::Transformable::getTransform() const", referenced from:
Pixels::draw(sf::RenderTarget&, sf::RenderStates) const in main-de105c.o
"sf::Time::asSeconds() const", referenced from:
Pixels::updatePixels(sf::Time) in main-de105c.o
"sf::Window::isOpen() const", referenced from:
_main in main-de105c.o
"typeinfo for sf::Transformable", referenced from:
typeinfo for Pixels in main-de105c.o
"vtable for sf::VertexArray", referenced from:
sf::VertexArray::~VertexArray() in main-de105c.o
NOTE: a missing vtable usually means the first non-inline virtual member function has no definition.
ld: symbol(s) not found for architecture x86_64
clang: error: linker command failed with exit code 1 (use -v to see invocation)
编译：
g++ main.cpp -I /usr/local/include -L /usr/local/lib -lsfml-graphics -lsfml-window -lsfml-system
或使用clang ++：
clang++ -std=c++11 -stdlib=libc++ main.cpp -o main -I /usr/local/include -L /usr/local/lib -lsfml-system -lsfml-window -lsfml-graphics