SFML-尝试从矢量绘制精灵时程序崩溃

Question

I am writing this relatively simple program to fire a small projectile from a moving character when the space bar is pressed.

The program compiles without any errors(in code blocks) and runs until the space bar is pressed. Instead of launching the projectile, the program promptly crashes.

I think I have been able to isolate the crash to the line where I draw the projectiles to the screen(ln. 83). I just used cout statements on the lines before and after and the second statement didn't show.

for (int ii = 0; ii < inMotion.size(); ii++)
{
    window.draw(inMotion[ii].bulletSprite);
}

I believe that all of my code will be necessary to address this issue so I have posted all of it.

#include <iostream>
#include <SFML/Graphics.hpp>
#include <string.h>
#include <math.h>
#include <vector>

using namespace std;
class Projectile
{
public:
    Projectile(int, string);
    void moveBullet();
    sf::Sprite bulletSprite;
private:
    sf::Texture bulletTexture;
    int speed;
    string bulletTextureString;
};

Projectile::Projectile(int s, string t)
{
    speed = s;
    bulletTextureString = t;
    if(!bulletTexture.loadFromFile((bulletTextureString).c_str()))
    {
        cout << "error";
    }
    bulletSprite.setTexture(bulletTexture);
}
void Projectile::moveBullet()
{
    bulletSprite.move(speed, 0);
}

class thePlayer
{
public:
    void Fire(sf::Time);
    void Walk();
    void Draw(sf::RenderWindow&);
    void Create(string);
    sf::Time lastShot;
private:
    vector<Projectile> inMotion;
    sf::Texture playerTexture;
    sf::Sprite playerSprite;
    string playerTextureString;
    int moveSpeed = 5;

}; 

void thePlayer::Create(string s)
{
    playerTextureString = s;

    if(!playerTexture.loadFromFile((playerTextureString).c_str()))
    {
        cout << "error";
    }
    playerSprite.setTexture(playerTexture);
}
void thePlayer::Fire(sf::Time time)
{
    sf::Time shotDelay = sf::milliseconds(100);
    if(time - lastShot >= shotDelay)
    {
        if(sf::Keyboard::isKeyPressed(sf::Keyboard::Space))
        {
            Projectile bullet(15, "fireball.png");
            bullet.bulletSprite.setPosition(playerSprite.getPosition());
            inMotion.push_back(bullet);
        }
    } 
    for(int ii = 0; ii < inMotion.size(); ii++)
    {
        inMotion[ii].moveBullet();
    }
}
void thePlayer::Draw(sf::RenderWindow& window)
{
    for (int ii = 0; ii < inMotion.size(); ii++)
    {
        window.draw(inMotion[ii].bulletSprite);
    }
    window.draw(playerSprite);
}
void thePlayer::Walk()//awsd standart movement
{
    int x = 0;
    int y = 0;
    if(sf::Keyboard::isKeyPressed(sf::Keyboard::A))
    {
        x-= moveSpeed;
    }
    else if(sf::Keyboard::isKeyPressed(sf::Keyboard::D))
    {
        x+= moveSpeed;
    }
    if(sf::Keyboard::isKeyPressed(sf::Keyboard::W))
    {
        y-= moveSpeed;
    }
    else if(sf::Keyboard::isKeyPressed(sf::Keyboard::S))
    {
        y+= moveSpeed;
    }
    playerSprite.move(x, y);
}

class Game
{
public:
    void Update(sf::RenderWindow&, sf::Time);
    void Start(sf::Time);
    sf::Clock clock;
    thePlayer player;

private:

};

void Game::Start(sf::Time time)
{
    player.Create("block.png");
    player.lastShot = time;
}
void Game::Update(sf::RenderWindow& window, sf::Time time)
{
    player.Fire(time);
    player.Walk();
    player.Draw(window);
}

int main()
{
    sf::RenderWindow window(sf::VideoMode(1000, 1000), "Menu");
    window.setFramerateLimit(60);
    Game theGame;
    sf::Clock clock;
    sf::Time startTime = clock.restart();
    theGame.Start(startTime);
    while (window.isOpen())
    {
        sf::Event event;
        while (window.pollEvent(event))
        {
            if (event.type == sf::Event::Closed)
                window.close();
        }

        window.clear(sf::Color::White);
        sf::Time elapsed = clock.getElapsedTime();
        theGame.Update(window, elapsed);
        window.display();
    }
    return 0;
}

Thanks so much for the help.

EDIT: I tried using the debugger but couldn't figure anything out. A link to a good article on codeblocks debugging would be great.

Answer 1

I was able to solve this myself. I figured out that I had to reference the Bullet class by pointer, and make sure the texture was also public. I was also using constructors wrong, and got rid of those.

My approximate solution was this...

void thePlayer::Fire(sf::Time time)
{
    sf::Time shotDelay = sf::milliseconds(100);
    if(time - lastShot >= shotDelay)
    {
        if(sf::Keyboard::isKeyPressed(sf::Keyboard::Space))
        {
            Projectile *bullet = new Bullet;
            bullet->bulletSprite.setPosition(playerSprite.getPosition());
            inMotion.push_back(bullet);
        }
    } 
    for(int ii = 0; ii < inMotion.size(); ii++)
    {
        inMotion[ii]->moveBullet();
    }

also had to change vector declaration in class

//...
vector<Bullet*> Bullets;
//...

and thanks again to the people who tried to answer.

Answer 2

Well, you're coding the game quite wrong !

What I suggest:

• You should create a player and a bullet classes,

• each class as a render method and an update method - the update method has a dt (elapsed time till last frame) parameter,

• the player class has a "move" and a "fire" methods,

• in the game loop, you first read input (and call the move or fire method if needed), update all the objects (player and bullets position) and draw all,

• the move method should give velocity to the player,

• the fire method should create bullets with velocity,

• the update method should compute the new position (with velocity and dt),

• player and bullet could derivate from a basis game element class (witch compute position, collisions, etc...).

Answer 3

You have to reset the clock:

sf::Time elapsed = clock.restart();

And you should load the texture of the projectile only once, and use it in all instances of the class Projectile.