Entity Manager

[p5ych0]

I'm having trouble with managing entities; I'm always getting "vector iterator not incrementable ".

(below is some pseudo code)

class Game;
class Entity {
public:
    void update(sf::Time dt, Game& game) {
        game.addEntity(); //ERROR IS HERE
    }
};
 

class Game {
public:
    Game() : mEntities() {
        addEntity();
    }

    void addEntity(Entity* e) {
        mEntities.push_back(e);
    }

    vector<Entity*> mEntities;
};
 

When I try calling 'addEntity()' from a different class I get an error. 

[math1992]

It's more an C++ issue than a SFML one...

But

void addEntity(Entity* e)
 

is waiting for an Entity*, but you do not pass any in here

game.addEntity();
 

[p5ych0]

Well I fixed that issue, and now I'm still getting the same error.

[math1992]

Can I see what you did, I am pretty sure you did not fix it properly.

[p5ych0]

Well in my Game.cpp I have methods for updating, rendering, etc.

void Game::update(sf::Time dt) {
    for (auto& it : mEntities)
        it->update(dt);
}

void Game::render() {
    for (const auto& it : mEntities)
        mWindow.draw(*it);
}

void Game::addEntity(Entity* e) {
    mEntities.push_back(e);
}
 

[eXpl0it3r]

Well compiler errors are a wonderful thing since they point you directly to the related code, unlike your post that just says that there's an error *somewhere*.

[ElysianShadow]

Well in my Game.cpp I have methods for updating, rendering, etc.

void Game::update(sf::Time dt) {
    for (auto& it : mEntities)
        it->update(dt);
}

void Game::render() {
    for (const auto& it : mEntities)
        mWindow.draw(*it);
}

void Game::addEntity(Entity* e) {
    mEntities.push_back(e);
}
 

Not sure if I'm right or not, but shouldn't your ranged based loops have the following format instead of how you did it? :

     for ( Entity* e : mEntities )
     {
          /* do stuff */
     }

 

Or is that the same thing as what you already have?

[dabbertorres]

It's the "same". The auto keyword gets the correct type for you upon compilation.

[ElysianShadow]

It's the "same". The auto keyword gets the correct type for you upon compilation.

Oh thats right  I was thinking of something else, but that makes sense

[p5ych0]

Do you think it's because I add another entity in another entity's 'update' function, and the vector is getting invalidated?

[Nexus]

Well, this forum is actually for SFML-related problems. We occasionally answer other questions related to game development, but C++ language-specific questions shouldn't be the standard, there are better places for them (e.g. C++ forums, StackOverflow).

But if you ask here, you have to adhere to the forum rules, in particular you should post a minimal complete example that reproduces the problem. You should also try with the debugger to find out as much as possible. This reduces the amount of guesswork on our side, and you will get a meaningful answer much faster.