C++ SFML Array Error: Access violation reading location 0xC0000005

Question

I am making a game with C++ and SFML, and I am having a problem during rendering various items with array. When I try to draw an array of sprites, the debugging is alright, and there are no warning and errors, but my game program runs only 20 seconds, then it stops running, and says, 'Unhandled exception at 0x7C50CF2E(sfml-graphics-d-2.dll), ECOVID-19 SFML.exe): 0xC0000005: Access violation reading location 0xCCCCCCD0.' I did everything I can, but I don't know why this exception occurs. Here are my codes that I suspect the causation of the error. Thank you for reading in spite of my poor English.

 #include <SFML/Graphics.hpp>
 ...
 using namespace std;
 using namespace sf;
 ...

 int main () {
 ...

 //item Sprites

 Texture bombTex;
 bombTex.loadFromFile("images/bomb.png");
 Sprite bomb;
 ...
 Texture bomb2Tex;
 bomb2Tex.loadFromFile("images/bomb_2.png");
 Sprite bomb_2;
 ...
 Texture cakeTex;
 cakeTex.loadFromFile("images/cake.png");
 Sprite cake;
 ...
 Texture coffeeTex;
 coffeeTex.loadFromFile("images/coffee.png");
 Sprite coffee;
 ...
 Texture chickenTex;
 chickenTex.loadFromFile("images/chicken.png");
 Sprite chicken;
 ...
 Texture pizzaTex;
 pizzaTex.loadFromFile("images/pizza.png");
 Sprite pizza;

 //item array (I made an item array to display & render various items in the game screen.)
 Sprite item[10]; //Although I change the array size to 4 or 5, the same exception occurs.
 item[0] = bomb;
 item[1] = coffee;
 item[2] = bomb_2;
 item[3] = chicken;
 item[4] = pizza;

 std::vector<Sprite> items;
 items.push_back(Sprite(item[4]));

 ...

 while (window.isOpen())
 {   ...
     ...
  for (size_t i = 0; i < items.size(); i++)
  {
     if (humanArr[index].getGlobalBounds().intersects(item[i].getGlobalBounds())) 
     //humanArr[index] is a player Sprite.
      {
         ...
          items.erase(items.begin() + i);
       }
   }
   ...
  window.clear();
   ...
  for (size_t i = 0; i < items.size(); i++)
     {
         window.draw(item[i]); // <- the exception error occurs here.
      }

   ...
 window.display();
  }
 return 0;
}

std::vector<Sprite> items; -- Does Sprite have correct copy semantics? If not, then having a vector of Sprite will not work out too well. — PaulMcKenzie
Does vector items grow with time? If so, then in the loop you say .intersects(item[i].getGlobalBounds()), if items size is bigger than item, then you access out of range — Alexey Larionov
There is a lot of code ommitted, so it's hard to tell. Are all of the Textures still in scope when you draw the sprites? — 0x5453
Seems possible that some mismatch between items and item is the cause. Your draw loop assumes that item is at least as big as items but maybe this isn't the case. Just having two parallel data structures like that is a bit dubious. — john

Nelson Nelson · Accepted Answer · 2020-08-20T20:08:41

What may be happening is that when you copy the Sprite item[10]; to the std::vector<Sprite> items; the Sprite class is making a shallow copy. It means that if the Sprite class is allocating any memory with new operator and storing it in a member pointer, then the shallow copy will only copy the address to which the pointer is pointing. When you do call items.erase(items.begin() + i); the destructor of the Sprite will be called, and in the destructor it may be calling delete in that pointer to some resourse.

When you call window.draw(item[i]); the library will try to use that resource and will find an invalid address.

What I suggest is that you don't use the Sprite item[10]; and only the std::vector<Sprite> items; , like this:

std::vector<Sprite> items;

items.push_back(bomb);
items.push_back(coffee);
...
window.draw(items[i]);

You don't need to use an intermediate array, just the std::vector<Sprite>;

C++ SFML Array Error: Access violation reading location 0xC0000005

1 Answers