Vector subscript out of range - c++

Question

i have a little problem with my game. When i'm trying to check that the bullet and ennemy are colliding i'm randomly getting an error "Vector subscript out of range", im not sure that this is a problem, but i'm deleting my vector in two places:
//Checking if enemy is crossing a bullet
for (size_t i = 0; i < ennemies.size(); i++)
{
ennemies[i].update(player);
if (player.getGlobalBounds().intersects(ennemies[i].getGlobalBounds()))
{
player.kill();
}
for (size_t j = 0; j < bullets.size(); j++)
{
if (ennemies[i].getGlobalBounds().intersects(bullets[j].getGlobalBounds()))
{
ennemies.erase(ennemies.begin() + i);
bullets.erase(bullets.begin() + j);
ilosc--;
}
}
}
Here is the second place:
for (int i = 0; i < Level::LEVEL_HEIGHT; i++)
{
for (int j = 0; j < Level::LEVEL_WIDTH; j++)
{
if (level.tiles[i][j].tileType != 0)
{
if (x.intersects(map[i][j].getGlobalBounds()))
kolX = true;
else if (y.intersects(map[i][j].getGlobalBounds()))
kolY = true;
for (int k = 0; k < bullets.size(); k++)
{
if (bullets[k].getGlobalBounds().intersects(map[i][j].getGlobalBounds()))
{
bullets.erase(bullets.begin() + k);
ilosc--;
}
}
}
}
}
and here is the whole code of a main class:
#include "Engine.h"
Engine::Engine()
{
//wczytywanie bg
bgTexture.loadFromFile("data\\textures\\bg.png");
bgSprite.setTexture(bgTexture);
//wczytywanie textur
for (int i = 1; i < level.iloscTextur; i++)
{
tiles[i].loadFromFile("data\\textures\\tiles.png", IntRect((i-1)*level.TILE_WIDTH, 0, 32, 32));
}
//ustawianie kafli
for (int i = 0; i < Level::LEVEL_HEIGHT; i++)
{
for (int j = 0; j < Level::LEVEL_WIDTH; j++)
{
if (level.tiles[i][j].tileType != 0)
{
map[i][j].setPosition(j * Level::TILE_WIDTH, i * Level::TILE_HEIGHT);
map[i][j].setTexture(tiles[level.tiles[i][j].tileType]);
}
}
}
}
Engine::~Engine()
{
}
//Renderowany poziom gry
void Engine::runEngine(RenderWindow & window)
{
//Zegary do pętli stałokrokowej, pocisków i przeciwników
Time UpdateTime = Time::Zero;
Time czasOdPocisku = Time::Zero;
Time czasDoSpawnu = Time::Zero;
Clock przeciwnicy;
Clock zegar;
Clock czasPocisku;
const Time StepTime = seconds(1.f / 60.f);
const Time WaitTime = seconds(0.1);
Time EnemySpawn = enemy.losujSpawn();
bool menu = false;
while (!menu)
{
Time czas = zegar.restart();
UpdateTime += czas;
//Pętla aktualizujaca logikę gry
while (UpdateTime > StepTime)
{
czasOdPocisku = czasPocisku.getElapsedTime();
czasDoSpawnu = przeciwnicy.getElapsedTime();
UpdateTime -= StepTime;
Event event;
Vector2f mouse = window.mapPixelToCoords(Mouse::getPosition(window));
player.update(mouse);
if (window.pollEvent(event))
{
if (event.type == Event::Closed)
menu = true;
if ((Keyboard::isKeyPressed(Keyboard::Left) && WaitTime < czasOdPocisku) || (Keyboard::isKeyPressed(Keyboard::Right) && WaitTime < czasOdPocisku) ||
(Keyboard::isKeyPressed(Keyboard::Up) && WaitTime < czasOdPocisku) || (Keyboard::isKeyPressed(Keyboard::Down) && WaitTime < czasOdPocisku))
{
czasPocisku.restart();
bullets.push_back(bullet);
bullets[ilosc].addBullet(player);
ilosc++;
}
}
//Spawn przeciwników
if (EnemySpawn < czasDoSpawnu)
{
czasDoSpawnu = przeciwnicy.restart();
EnemySpawn = enemy.losujSpawn();
for (int i = 0; i < enemy.losujPrzeciwnikow(); i++)
ennemies.push_back(enemy);
}
//aktualizacje logiki
for (int i = 0; i < bullets.size(); i++)
{
bullets[i].update();
}
//Checking if enemy is crossing a bullet
for (size_t i = 0; i < ennemies.size(); i++)
{
ennemies[i].update(player);
if (player.getGlobalBounds().intersects(ennemies[i].getGlobalBounds()))
{
player.kill();
}
for (size_t j = 0; j < bullets.size(); j++)
{
if (ennemies[i].getGlobalBounds().intersects(bullets[j].getGlobalBounds()))
{
ennemies.erase(ennemies.begin() + i);
bullets.erase(bullets.begin() + j);
ilosc--;
}
}
}
czyKoliduje(player.ruch(StepTime));
}
window.clear();
window.draw(bgSprite);
//Rysowanie poziomu
for (int i = 0; i < Level::LEVEL_HEIGHT; i++)
{
for (int j = 0; j < Level::LEVEL_WIDTH; j++)
{
window.draw(map[i][j]);
}
}
//Rysowanie pociskow
for (int i = 0; i < bullets.size(); i++)
{
window.draw(bullets[i]);
}
for (int i = 0; i < ennemies.size(); i++)
{
window.draw(ennemies[i]);
}
window.draw(player);
window.display();
}
}
//Kolizje
void Engine::czyKoliduje(Vector2f ruch)
{
FloatRect x = player.getGlobalBounds();
FloatRect y = player.getGlobalBounds();
x.left += ruch.x;
y.top += ruch.y;
bool kolY = false, kolX = false;
for (int i = 0; i < Level::LEVEL_HEIGHT; i++)
{
for (int j = 0; j < Level::LEVEL_WIDTH; j++)
{
if (level.tiles[i][j].tileType != 0)
{
if (x.intersects(map[i][j].getGlobalBounds()))
kolX = true;
else if (y.intersects(map[i][j].getGlobalBounds()))
kolY = true;
for (int k = 0; k < bullets.size(); k++)
{
if (bullets[k].getGlobalBounds().intersects(map[i][j].getGlobalBounds()))
{
bullets.erase(bullets.begin() + k);
ilosc--;
}
}
}
}
}
if (!kolX)
player.move(Vector2f(ruch.x, 0));
if (!kolY)
player.move(Vector2f(0, ruch.y));
}

Answer 1

All of your loops that are calling erase() on containers are not taking into account that the size of the containers change when you erase items from them. To properly loop through a container while erasing items from it, you should use iterators instead of indexes. erase() returns a new iterator that points to the item after the erased item, so you can continue looping.
std::vector<enemy>::iterator i = ennemies.begin();
while (i != ennemies.end())
{
i->update(player);
if (player.getGlobalBounds().intersects(i->getGlobalBounds()))
{
player.kill();
}
bool hit = false;
for (std::vector<bullet>::iterator j = bullets.begin(); j != bullets.end); ++j)
{
if (i->getGlobalBounds().intersects(j->getGlobalBounds()))
{
hit = true;
i = ennemies.erase(i);
j = bullets.erase(j);
ilosc--;
break;
}
}
if (!hit)
++i;
}
for (int i = 0; i < Level::LEVEL_HEIGHT; i++)
{
for (int j = 0; j < Level::LEVEL_WIDTH; j++)
{
if (level.tiles[i][j].tileType != 0)
{
if (x.intersects(map[i][j].getGlobalBounds()))
kolX = true;
else if (y.intersects(map[i][j].getGlobalBounds()))
kolY = true;
std::vector<bullet>::iterator k = bullets.begin();
while (k != bullets.end())
{
if (k->getGlobalBounds().intersects(map[i][j].getGlobalBounds()))
{
k = bullets.erase(k);
ilosc--;
}
else
++k;
}
}
}
}
With that said, you might consider using std::remove_if() instead of manual erase() loops:
template<typename SourceType, typename TargetType>
struct intersectsBounds
{
TargetType &m_target;
intersectsBounds(TargetType &target) : m_target(target) {}
bool operator()(const SourceType &source) const
{
return source.getGlobalBounds().intersects(m_target.getGlobalBounds());
}
};
std::vector<enemy>::iterator i = ennemies.begin();
while (i != ennemies.end())
{
i->update(player);
if (player.getGlobalBounds().intersects(i->getGlobalBounds()))
{
player.kill();
}
std::vector<bullet>::iterator j = std::remove_if(bullets.begin(), bullets.end(), intersectsBounds(*i));
if (j != bullets.end())
{
i = ennemies.erase(i);
int numErased = std::distance(j, bullets.end());
bullets.erase(j, bullets.end());
ilosc -= numErased;
}
else
++i;
}
for (int i = 0; i < Level::LEVEL_HEIGHT; i++)
{
for (int j = 0; j < Level::LEVEL_WIDTH; j++)
{
if (level.tiles[i][j].tileType != 0)
{
if (x.intersects(map[i][j].getGlobalBounds()))
kolX = true;
else if (y.intersects(map[i][j].getGlobalBounds()))
kolY = true;
std::vector<bullet>::iterator k = std::remove_if(bullets.begin(), bullets.end(), intersectsBounds(map[i][j]));
if (k != bullets.end())
{
int numErased = std::distance(k, bullets.end());
bullets.erase(k, bullets.end());
ilosc -= numErased;
}
}
}
}