Messages

1

Window / Re: Window display() and removing elements of a vector array

« on: February 20, 2014, 01:20:21 am »

Hi thank you for the advice. I managed to solve the problem. I don't know if it is customary to update a solved problem or just annoying, please tell me if it is.

Any way, the main problem was that I used the actual colliders in the position update instead of updating via the vector array! I am suspecting that lead to confusion for the compiler and that when you push something into the vector you make a copy of it. any way it works now.

The reason to why I assigned it nullptr was to not have a dangling pointer.. I'll have to research the smart pointers, they seem convenient.

Awesome and fast help. thanks again.

2

Window / Re: Window display() and removing elements of a vector array

« on: February 19, 2014, 09:29:43 pm »

or did you mean I could remove it in the collision detection loop btw??

3

Window / Re: Window display() and removing elements of a vector array

« on: February 19, 2014, 09:16:14 pm »

Why don't you break if a collision is found, or swap immediately instead of once at the end?

It is not a collision detection loop I try to find the collider to remove after a collision have already occurred.

But I suppose I could have swapped immediately instead.

well lol It sure looks awful now that you've mentioned it about the count variable but I guess I wasn't focusing on trivialities such as that, but to get this to work before I have pulled all my hair from my head

But thanks for the help I will try the remove_if and give the erase another go

4

Window / Window display() and removing elements of a vector array

« on: February 19, 2014, 08:05:17 pm »

Hi! I don't know if there is a similar post in here already, there were just too many posts to go through them all.

I have this strange problem. I am working on a beginner project in a game development course.

I am doing colliders and collisions.

What I want to do is I want to remove one specific collider in case it is colliding. I have made a crude collider identification system using ints. 1 means it is a player and 2 means it is an enemy. (I am aware of the inconvenience of this system, I will change that to enums as soon as I get it working. the problem is not the identification system.)

The problem is that when these two, player and enemy, are colliding I want to remove the enemy collider. I have a function that iterates trough my vector via their index and if the current element's collider is an enemy, I delete the collider, set it to nullptr, swap this element with the last one and run pop_back(). I have debugged and it works, I have doublechecked to track the collider in it's vector.

I have drawn rectangles for each of these colliders, the one I delete only synchronize its position to its rectangle (sf::RectangeShape() ) if (collider != nullptr).

When it's time for sf::renderwindow::display() it crashes. All the other collisions work like I want them to, meaning the displayfunction works.

The remove function is only called if player and enemy have collided. this turns a bool to true. what am I missing. I thought this is relevant because I use SFML and it crashes (from what I can tell when everything is supposed to display)

All I get for an error message is <the program> has triggered a breakpoint (not one of mine) I use VS Ultimate 2012

code:

void CollisionManager::RemoveCollider()
{
        int count;
        count = 0;
        int index;
        for (int i = 0; i < m_axRectColliders.size(); i++)
        {
                if (m_axRectColliders[i]->GetEnemy() == 2)
                {
                        delete m_axRectColliders[i];
                        m_axRectColliders[i] = nullptr;
                        index = count;
                }
                else
                {count++;}
        }
        std::swap(m_axRectColliders[index], m_axRectColliders.back());
        m_axRectColliders.pop_back();
}

only updating if it is not nullptr m_rect2 is the collider, m_rectShape2 is its shape

if (m_rect2 != nullptr)
        {
                m_rect2->SetPositionX(m_rectShape2.getPosition().x);
                m_rect2->SetPositionY(m_rectShape2.getPosition().y);
        }

the update takes place before the removal:

mgr->CheckCollisionRectVsRect();
        m_rectShape.setPosition(m_rect->GetPosition());
        m_rectShape2.setPosition(m_rect2->GetPosition());
        if (mgr->GetPlayerVsEnemy())
        {
                mgr->RemoveCollider();
                mgr->SetPlayerVsEnemy(false);
        }

I set the playershape(m_rectshape) to it's collider's position and the enemy's the same. this have no effect on my problem because it happens before I call RemoveCollider() and I have tried commenting the position updates away with no result. Why I do this is so that I can push them away with each other. I played a little with the collisions before this.

And here's where the program crashes:

void GameState::Draw()
{






        m_pWindow->clear(sf::Color(0x11,0x22,0x33,0xff));
        m_pWindow->draw(m_shape);
        m_pWindow->draw(m_shape2);
        m_pWindow->draw(m_rectShape);
        m_pWindow->draw(m_shape3);
       
        m_pWindow->draw(m_rectShape2);
        m_pWindow->draw(m_rectShape3);
        m_pWindow->display();
}

at the end of the scope.

I can't think of anything else I have tried different things I am sure it is something about how I remove it but I just don't know what...